I feel a project coming on

[opel2000]

Well what a chuffing week.........

Last weekend saw me fitting seat belts and interior bits, I was going to get this done after doing headlining but the seatbelts were like cardboard so I washed them and needed them to dry before fitting them (obvious really)

Nice thing though is that the interior is complete, apart from parcel shelf, even fitted the damn sterereo and speakers in the doors.

Also spent a while to get the glass seating correctly, passenger door is absolutely spot on. Drivers door is being a right bast. The problem is that the glass needs to be moved back towards the C pillar a tad, and it also needs to be adjusted slightly on the stops, but when the slide thing that sits at the rear bottom of the glass fell off, I bonded it back into place a while ago when the window was out of adjustment, and now I can't adjust it back enough, if it weren't for the fact the glass aint brilliant I would have sorted this out, but got a feeling something will turn up for me here.

Got a oil filter threaded piece from the main dealers this week, which meant that, I could actually put oil in the car at last, so I went and got a can full of fuel too, as there was no reason why this should not fire up.

Primed the oil pump. Removed plugs and spun the engine over a few times hoping to see oil pressure light go out, but it didn't, can only hope that when it fires up it will go out.

FOOK would it fire up.

Checked for fuel .... Fine

Checked for spark .... Fine

So can only be plug leads incorrect...

Checked the leads .... Fine...... HMMMM???

As it turned over it was spitting back through the inlet,,,,,, it simply shouldn't be doing this at all it was as if the inlets were open when trying to fire up checked the timing marks that I wasn't 180 degree out and after looking and looking I spotted this..........

YEP! the timing marks I had set the engine up to were the painted ones on the pulleys, never did I look to see whether these were correct as I simply could not ever imagine someone painting on random timing marks,,,,,,,,,,, Just WHY some fuckwit painted these on is absolutely beyond me.

So I turned carnk 180 degrees to put pistons halfway down the bores and removed timing belt etc in order to try and set the timing marks up correctly.

When turning the cams over they did seem to feel to snap shut when coming off of the cam peaks, so hoping there is no bent valves or piston damage, also compression felt very very good when turning the engine over by hand.

Now realised that the plug leads were now wrong too as the dizzy dowel that locates in the ex cam meant I had No.1 plug lead in No.2 firing position.

Tried to fire up again and still nothing,,,,

Swapped fuel lines round and it fired up for a few seconds,,,

Wouldn't fire up again though,,,,

checked plugs and they were dry as a bone,,,,

swapped fuel lines back round,.

It fired a few times, now simply won't fire up, checked plugs, plugs were wet, but nowhere near as wet as I would have imagined.

Although there is fuel at the fuel rail, I'm suspecting either pressure regulator not good, or a blockage in the fuel rail/injectors.

So gonna whip off the fuel rail and put some pressure behind each injector in turn, before putting 12V to each injector to see what each one is doing.

If they are fine and after having blown through the fuel rail then I'll assume it will be the regulator.

The good thing is though that it did fire up....... so it will run, just need to sort out why it won't run properly.

Also my patchwork quilt sump doesn't leak,,,,, er, may have made it a bit on the big side of things though seems to hold a LOT of oil, and oil pressure is up and up good and high when turning over.

[mickappy]

someones just marked it up n slipped a belt on the quick way,

id be absolutly amazed if the valves arnt bent. theres feck all clearance.

but i see you spun the engine to prime the pump so they should be fine..

strange. let me know if u need owt mate ive just about everything for these engines a few time over.

[opel2000]

TBH Mick, I'm sure I would have fucked something here, I can't see why I should waste any more time trying to see if it will start, really I need to take the head off and have a look to see if there is damage, and like you said I too would be damn surprised if I've not damaged something. Just with cash so damn low at the moment can't even afford a damn headgasket yet alone any replacement parts.

So damn irritating when being so damn close, and many thanks for your offer mate, very much appreciated, will see how everything goes

[opel2000]

HMMmm

Just found out that the fuel pressure could be a bit onthe low side of things...

Pressure regulator was taken off of a fuel rail with blue injectors, apparently these run at 2.5 bar where the cream injectors want a 3 bar fuel pressure regulator.

OK there is only 0.5 bar in it (approx 7psi) but there is one issue already.

[mickappy]

pressure test on the cylinders would be worth it b4 u decide to whip the head off mate.

also ive known them not run well with the 3bar injectors in. id stick to the 2.5 for now till u know its right.

[mantasrme]

Is that picture before or after you re-set the marks? The white marks do look a little out but the timing marks at the top of the pulleys look right (although the inlet notch on the cam cover is hard to see)

Rather than all the work taking the head off a compression check might show if there's any issues

As for the none starting when i first tried to fire my 16v it splutteed once or twice but would not fire. Plugs got wet but not soaking and everything else looked fine.

So i wired in the error code light and checked for error codes, only one that came up was the crank sensor.

Now this will come up as an error if you check the codes without the engine running, because the ecu isn't getting a reading from it.

But as there was no other code and the car wouldn't start i swapped the crank sensor.

She fired up straight away

If you haven't wired up the engine warning light its easy to do.

Pin 22 from the ecu brown/blue wire goes to a lamp and a 12v feed to the other side

Then when you earth pin 13 brown/yellow it puts the ecu into diagnostics mode (i've put mine to a switch, so i can just flick the switch and check codes whenever i want)

[opel2000]

Hey thanks fella's

TBH 2.5 bar should create enough spray pattern pressure for the injectors.

Also the Crank sensor is a brand new item from GM ££££ how much did this cost? thieves!

David yes mate that pic is after I had corrected the timing, and thanks for the info on the error code wiring, I had intended to do this but put it aside due to trying to get the car done as soon as poss.

And yes thanks Mick, a pressure test would be a damn good idea, but experience of building engines says that I may (Quote "MAY" ) be ok, as when turning over by hand and you are reaching the top of the stroke (with socket and ratchet on crank pulley) the compression is pushing the ratchet back as it should do.

Hoping that I just may have been very very very lucky with this....... but keep thinking that is nonsense and valves are stuffed.

Been reading about on various forums about running issues on XE engines, and all the thoughts i've had have been echo'd over and over again, think i'm gonna go and get on with the exhaust and get at least one box fitted, but can guarantee that as soon as i run electric out there for the grinders and the welder it is gonna piss it down again, got frigging soaked yesterday.

Edited May 8, 2011 by opel2000

[opel2000]

Well when i do get this to fire up I thopught it best that it be running with an exhaust fitted.

So Many thanks to Bobby and Martin for helping me out with various bits over the weekend.

First off is Big Ian Goachers back box off of his old 400, need hangers on this and all I had was 6mm stainless studding, not ideal as it will only bend so much before snapping but it will get the box in position for a quick correct fix at a later date as soon as funds allow for better material.

Secondly a bit of mild steel was hand rolled and tacked into place to fit into place over the downpipe.

Then held in position by a jack at the other end to get the height for the back box entry point.

Then after measuring the hangers on the underside of floorpan to the centre of the exhaust a got a dimension of 7" (hmm can't be right) and it wasn't

After fooking about I ended up with this, now if Carlsberg made exhaust brackets/hangers they would look nothing like this :lol:

With Box now in place it needed fettling to line up wth the tube from the down pipe, box is hanging approx 1" beneath the rubber damper on the underside of floorpan.

Box now fettled and lines up spot on, and i used the piece I cut out to weld back over the too large a gap that i cut out of the box inlet bit of pipe.

Then i simply cut a couple of wedges out of the pipe "downpipe to box" to put a stepped bend in it to line it up with the box, and all is well and good, high enough to floorpan and clears everything, box sitting very very good, and a mate of mine supplied me with a piece of Exhaust tube which he was going to use for a project but never used, this has bends in that will allow me to cut and cobble an over axle piece to back box "Cheers Mate " absolute godsend especially when cash is so damn tight.

Can't find the piccies of the rest of exhaust, but pretty boring anyway, shall roll some stainless up tomorrow so i can get some joiners made properly, back box is sitting pretty damn shite at the mo, so may need to alter the box and fit a better hanger, already cobbled one hanger up on it, but I can take dimensions from that to make a correct hanger.

THEN, i shall be compression testing the engine.... mate dropped off his compression tester today, and I shall then take the project from there.

If comp is good, then I'll check fuelling.

Then i'll go over everything, spark from coil, spark from plugs, leads in correct order, etc, etc,

Would be so nice to think that in a day or so I could actually be driving this and there will be one hell of a thankyou list to all concerned when this happens.

[rutts]

going back to fuel pressure blue should have 3.0 bar, creams 2.5 bar, if i read it wrong sorry.

if its a dizzy engine check you have all earths on fuel rail retaining bolts mine has three. two on left nut/bolt one on right,

Edited May 8, 2011 by rutts

[garymanc]

going back to fuel pressure blue should have 3.0 bar, creams 2.5 bar, if i read it wrong sorry.

if its a dizzy engine check you have all earths on fuel rail retaining bolts mine has three. two on left nut/bolt one on right,

thats what i thought as well,even though i have blues on 2.5 bar reg

might be worth trying the old 2p trick as well to see if it fires up

hope you get it sorted

[mickappy]

yes another very common problem is the fuel relay. thses seem to stop working when not used.

this got me when i first did my hatch, took 2 weeks to figure out i had a bad relay.

check theres vaultage at the pump when turning over.

[opel2000]

going back to fuel pressure blue should have 3.0 bar, creams 2.5 bar, if i read it wrong sorry.

if its a dizzy engine check you have all earths on fuel rail retaining bolts mine has three. two on left nut/bolt one on right

Was a bit unsure when I read this on a forum myself as the blue injectors have lots of little hols in the end unlike the cream type, so would have suumed they would have wanted a tad higher fuel pressure to create the spray pattern through the holes.

Fuel rail bolts/earths all present, clean and well fatsened.

Cheers Andy

thats what i thought as well,even though i have blues on 2.5 bar reg

might be worth trying the old 2p trick as well to see if it fires up

hope you get it sorted

Can't do the 2p trick as car is a T plate Manta (1978) and thinking about it, I can't recall where I took the feed for the fuel pump from, pretty damn sure it is powered from the Injection/ignition relay,,,, Hmm potential fault area to check.

yes another very common problem is the fuel relay. thses seem to stop working when not used.

this got me when i first did my hatch, took 2 weeks to figure out i had a bad relay.

check theres vaultage at the pump when turning over.

Mick, as per Gary, I was chewing this over lying in bed last night when unable to sleep, I have known these to be not good in the past, and thinbking about it this loom is off my old Calibra I decided to break the Calibra when it decided to idle only when I was overtaking a lorry one night, fook me it has now only just dawned on me that there could be a lot of issues with er, well pretty much everything.

Sure I have a spare relay knocking about, and also need to check that fuel pump is working properly, I know fuel pump is good as I used it in the Skyline engine bay to draw fuel up from the tank of the Skyline when the skyline pump failed the other year.

BUT must say.... it did seem odd when checking the fuel pipe orientation that there was not a lot of residual pressure when I removed the pipes.

I'm pretty sure (or hoping that I'm pretty sure) this is all down to fuelling.

Got a lot of work on PC today due to a very odd lack of emails coming through for Custom Solutions, but hoping to get the exhaust finished today to get back on with the running issue of this car.

Many thanks for your input people, all comments are very very much appreciated, especially as I do not know the XE engine and associated components particularly well.

Fooking great.......

No pics showing due to web hosting for custom solutions not actually being there for some reason.......

Been suspecting email issues with these tossers for a while now. Now I can't deal with my customers, just gets fooking better by the bast day

Edited May 9, 2011 by opel2000

[opel2000]

Wel well well, someone has been a lucky boy......... After reading on the Calibra forum about someone who couldn't fire up his XE and found 16 Valves bent . It turns out that NONE yes "0" of my valves are bent, turning over the engine on the starter gave compression readings of 190 to 200 PSI across the four cylinders.

So.....

Checked fuel pump connections were correctly orientated.

Put a battery on to the fuel pump and tried to fire it up. no difference the idea behind that was if the relay was a bit iffy I would still have fuel pressure at the injectors.

Relieved the pressure at the fuel rail and tried to fire up again without the extra batt on the fuel pump, and found pressure at the fuel rail.

Now back to suspecting sticking injectors, tried holding the fuel rail whilst turning engine over to see if they were squirting fuel out but the connectors kept coming off of the injectors, but pretty damn sure the middle 2 injectors were still connected.

So removed fuel rail completely and put some thinners down a hose to the fuel rail and fired up the compressor in order to put some pressure down onto the injectors before opening each one in turn by applying 12V, but smply succeeded in blowing one of the injectors out of the fuel rail, so with fuel hose full of thinners I just let gravity do it's work.

And tbh I was a bit disapointed to see each injector open to let the thinners through.

re-assembled everything after blowing through fuel rail to ensure no lumps of gristle or dead petrol drinking spiders were in there to block the injectors.

Checked the rotor arm position for no.1 at TDC after aligning the timing marks Again, and re-fitted plug leads in correct order.

Everything fitted and connected and in right order, and everything correct and still will not even cough or splutter.

[mickappy]

clive the fuel relay turns the whole ecu on not just the pump. daft question mate but have u got a spark??

[opel2000]

Yes mate, I have spark.

Just been reading through this lot which has explained some unknowns to me.... Especially as that Relay opens the injectors too according to this lot.

Motronic 2.5 operation Bosch

Motronic 2.5 is an enhancement of the Motronic 4.1 EMS fitted to earlier Vauxhall and Opel vehicles. It was first fitted in the1990 model year (late 1989) and is a fully integrated system that controls primary ignition, fuelling and idle control from within the same ECU. It is normally only fitted to 16 valve GM engines. The control unit contains three microprocessors for general control unit operation sequential injection

knock control

The Motronic ignition point and injection duration are jointly processed by the ECU so that the best moment for ignition and fuelling are determined for every operating condition. The injection function of the Motronic system is based on the well tried 'L' jetronic system, although a number of refinements have improved operation. A 55 pin connector and multi-plug connects the ECU to the battery, sensors and actuators.

Basic ECU operation

A permanent voltage supply is made from the vehicle battery to pin 18 of the ECU. This allows the self-diagnostic function to retain data of an intermittent nature. Once the ignition is switched on, a voltage supply to the ignition coil and to ECU pin 27 is made from the ignition switch. This causes the ECU to connect pin 36 to earth, so actuating the main fuel injection relay. A relay switched voltage supply is thus made to ECU pin 37, from terminal 87 of the main fuel injection relay. The majority of sensors (other than those that generate a voltage such the CAS, KS and OS), are now provided with a 5.0 volt reference supply from a relevant pin on the ECU. When the engine is cranked or run, a speed signal from the CAS causes the ECU to earth pin 3 so that the fuel pump will run. Ignition and injection functions are also activated. All actuators (Injectors, ISCV, FTVV etc), are supplied with nbv from the main relay and the ECU completes the circuit by pulsing the relevant actuator wire to earth.

Signal processing

Basic Ignition timing is calculated from the ignition map and engine load determines the basic injection pulse value. Correction factors are then applied for starting, idle, deceleration, part and full-load operation. The main engine load sensor is the AFS and the main correction factor is engine temperature.

Reference voltage

Voltage supply from the ECU to many of the engine sensors is at a 5.0 volt reference level. This ensures a stable working voltage unaffected by variations in system voltage. The earth return connection for most engine sensors is made through an ECU pin that is not directly connected to earth. The ECU internally connects that pin to earth via one of the ECU pins that are directly connected to earth.

ECU coding wires (where fitted)

Some vehicles equipped with Motronic 2.5 have certain ECU pins allocated as coding earths. The open circuit voltage at these pins is either nbv or at 5.0 volt reference level. Connection of the pin to earth indicates to the ECU that the vehicle is equipped with certain equipment. The non cat vehicle has pin 20 connected to earth and the catalyst equipped vehicle has pin 20 open circuit. The vehicle with AT has pin 21 connected to earth and the vehicle with MT has pin 21 open circuit.

Signal shielding

To reduce RFI, a number of sensors (ie CAS, HES, KS, amplifier and OS) use a shielded cable. The shielded cable is connected to the main ECU earth wire at terminal 19 to reduce interference to a minimum.

CAS

The CAS consists of an inductive magnet that radiates a magnetic field and a toothed disk. The disk is attached to the crankshaft or pulley and theoretically comprises 60 teeth set at 3° intervals around its circumference; each tooth being 3°wide. At a position some distance BTDC, two teeth are omitted as a reference to TDC and so a total of 58 teeth remain on the disk. As the crankshaft spins, and the teeth are rotated in the magnetic field, an AC voltage signal is generated and delivered to the ECU to indicate speed of crankshaft rotation. In addition, as the engine spins, the missing teeth generate a variation of the signal that serves as a reference to TDC to indicate crankshaft position. The peak to peak voltage of the speed signal (when viewed upon an oscilloscope) can vary from 5 volts at idle to over 100 volts at 6000 rpm. Because computers prefer their data as on/ off signals, the ECU utilises an analogue to digital converter (ADC) to transform the AC pulse into a digital signal.

Ignition

Data on load (AFS), engine speed (CAS), engine temperature (CTS) and throttle position (TS) are collected by the ECU, which then refers to a three dimensional digital map stored within its microprocessor. This map contains an advance angle for each operating condition, and thus the best ignition advance angle for a particular operating condition can be determined. When the throttle switch is closed, the ECU enters base timing mode and the timing is set at 10°.

Amplifier

The amplifier contains the circuitry for switching the coil negative terminal at the correct moment to instigate ignition. The signal received by the amplifier from the trigger is of an insufficient level to complete the necessary coil switching. The signal is thus amplified to a level capable of switching the coil negative terminal. Unlike earlier Vauxhall/ Motronic systems (in which the amplifier was contained in the ECU itself), Motronic 2.5 utilises a separate amplifier mounted on a heat sink plate adjacent to the coil. The ECU thus calculates the correct ignition dwell time and timing advance from data received from its sensors, and sends a signal to the amplifier which then switches the coil negative terminal. The advantage of a separate amplifier, is that if the amplifier fails, it is less costly to renew than a new ECU. Dwell operation in Motronic is based upon the principle of the 'constant energy current limiting' system. This means that the dwell period remains constant at around 4.0 to 5.0 ms, at virtually all engine running speeds. However, the dwell duty cycle, when measured in percent or degrees, will vary as the engine speed varies. A current limiting hump is not visible when viewing an oscilloscope waveform.

Ignition coil

The ignition coil utilises low primary resistance in order to increase primary current and primary energy. The amplifier limits the primary current to around 8 amps and this permits a reserve of energy to maintain the required spark burn time (duration).

Distributor

In the Motronic system, the distributor only contains secondary HT components (distributor cap, rotor and HT leads) and serves to distribute the HT current from the coil secondary terminal to each spark plug in firing order.

Knock sensor

The optimal ignition timing (at engine speeds greater than idle) for a given high compression engine is quite close to the point of onset of knock. However, running so close to the point of knock occurrence, means that knock will certainly occur on one or more cylinders at certain times during the engine operating cycle. Since knock may occur at a different moment in each individual cylinder, Motronic 2.5 employs the Knock Control unit – KCU (in the ECU) to pinpoint the actual cylinder or cylinders that are knocking. The Knock Sensor is mounted on the engine block and consists of a piezoceramic measuring element that responds to engine noise oscillations. This signal is converted to a voltage signal by the Knock Sensor and returned to the KCU for evaluation and action. Tests have shown that the 20XE & C20XE engines have a knocking frequency in the 15kHz frequency band. The KCU will analyse the noise from each individual cylinder and set a reference noise level for that cylinder based upon the average of the last 16 phases. If the noise level exceeds the reference level by a certain amount, the KCU identifies the presence of engine knock. Initially, timing will occur at its optimal ignition point. Once knock is identified, the Knock Control microprocessor retards the ignition timing for that cylinder or cylinders by 3ш. Approximately 2 seconds after knocking ceases (20 to 120 knock- free combustion cycles), the timing is advanced in 0.75ш increments until the reference timing value is achieved or knock occurs once more when the timing is retarded or This procedure continually occurs so that all cylinders will consistently run at their optimum timing. If a fault exists in the Knock Control processor, Knock control sensor or wiring, an appropriate code will be logged in the self-diagnostic unit and the ignition timing retarded by 10.5ш by the LOS program.

Cylinder Identification

In earlier Motronic systems the ECU does not recognise number one cylinder or indeed even the firing order. This is because it is actually unnecessary. When the crankshaft or distributor provides a timing signal, the correct cylinder is identified by the mechanical position of the crankshaft, camshaft, valves and ignition rotor. In systems where the injectors fire simultaneously, then the fuel will sit upon the back of an inlet valve until the valve opens. Since fuel injection occurs on an individual cylinder basis in Motronic 2.5, the ECU must be informed on which stroke a cylinder is actually on. This is achieved by a cylinder identification sensor attached to the distributor and which works on the Hall-Effect principle. The sensor identifies number one cylinder, and returns a signal to the ECU from which the identification of all the other cylinders can be calculated. The distributor is attached to the exhaust camshaft (the engine is DOHC in configuration) .

Octane coding

Because of the sophistication of the KCU and timing control an octane coding plug is not considered necessary for the 20XE & C20XE engines. Octane adjustment is automatically selected according to operating conditions. Motronic 2.5 is programmed with two different timing maps. These are Low Octane Number Map (more retarded timing) and High Octane Number Map (more advanced dwell angle). The KCU selects the appropriate map according to the following conditions.Once knocking combustion of more than 50 have occurred, the KCU switches to the Low Octane Map. Once approximately minutes of knock-free operation have passed, the KCU switches to the High Octane Map.

Fuel injection

The ECU or vehicle computer is programmed with a basic injector map. Information is then gathered from engine sensors such as the AFS, CAS, CTS, and TS. As a result of this information, the ECU will look-up the correct injector pulse duration right across the engine rpm, load and temperature range.

Fuel injection

The Motronic 2.5 system is a multi-point injection system and pulses the injectors sequentially - ie in firing order and once per engine cycle. Each injector is connected to the ECU via a separate ECU pin). Earlier Motronic systems (ie 4.1 and 1.5) pulse all injectors at the same time - ie simultaneously and twice per engine cycle During engine start from cold, the pulse duration and number of pulses (frequency) are increased to provide a richer air/fue mixture.

Fuel injectors

The fuel injector is a magnetically operated solenoid valve that is actuated by the ECU. Voltage to the injectors is applied from the main relay and the earth path is completed by the ECU for a period of time (called pulse duration) of between 1.5 and 10 milliseconds. The pulse duration is very much dependant upon engine temperature, load, speed and operating conditions. When the magnetic solenoid closes, a back EMF voltage of up to 60 volts is initiated. The fuel injectors are mounted in the inlet stubs to the engine inlet valves so that a finely atomised fuel spray is directed onto the back of each valve. Since the injectors are all pulsed simultaneously, fuel will briefly rest upon the back of a valve before being drawn into a cylinder.

Hot Wire Air mass meter (AFS)

Motronic 2.5 also uses a Hot Wire airflow sensor to measure the mass of air entering engine. From the air mass, an accurate fuel injection pulse can then be calculated. Hot Wire is a very accurate method of calculating the engine load (air input) and excludes the need for additional sensors to measure air temperature and air pressure. Automatic compensation for altitude is thus provided. The absence of moving parts improves reliability and lessens maintenance requirements. Essentially, the hot wire is so called because a heated wire is placed in the air intake. As air passes over the wire it has a cooling effect in proportion to the mass of air. As airmass increases or decreases according to engine load, the ECU adjusts the current flow to maintain the wire at its original resistance and temperature. By measuring the change in current flow, the ECU is able to determine the mass of air flow into the engine. As the current varies on the signal wire, so does the voltage and an indication of load can be assessed by measuring the variable voltage signal. Voltage is applied to the sensor from the system relay. If a fault exists in the Hot Wire AFS or wiring, an appropriate code will be logged in the self-diagnostic unit and a substitute value provided by the LOS program.

Hot wire burn-off

Over a period of time, deposits tend to build-up upon the hot wire and this can lead to contamination of the hot-wire. This is avoided with a `burn-off' function controlled by the ECU during engine shutdown. Approximately four seconds after the engine has been switched off, the ECU rapidly pulses the hot-wire terminal 4 of the AFS for 1.5 seconds. Burn-off will not occur if the engine speed has not exceeded 1000 rpm and the coolant temperature is under approximately 30° C.

CO pot

The CO pot mixture adjuster is a three wire potentiometer that allows small changes to be made to the idle CO. A 5.0 volt reference voltage is applied to the sensor and connected to the AFS earth return circuit. The third wire is the CO pot signal. As the CO pot adjustment screw is turned the change in resistance returns a voltage signal to the ECU that will result in a change in CO. The CO pot adjustment only affects idle CO. On catalyst equipped models, the CO pot has no effect and the CO is thus non-adjustable.

CTS

The CTS is immersed in the coolant system and contains a variable resistance that operates on the NTC principle. When the engine is cold, the resistance is quite high. Once the engine is started and begins to warm-up, the coolant becomes hotter and this causes a change in the CTS resistance. As the CTS becomes hotter, the resistance of the CTS reduces (NTC principle) and this returns a variable voltage signal to the ECU based upon the coolant temperature. The open circuit supply to the sensor is at a 5.0 volt reference level and this voltage reduces to a value that depends upon the resistance of the CTS resistance. Normal operating temperature is usually from 80° to 100° C. The ECU uses the CTS signal as a main correction factor when calculating ignition timing and injection duration.

Throttle switch

A throttle switch with dual contacts is provided to inform the ECU of idle position, deceleration, cruising and full-load (WOT) conditions. When the engine is at idle the idle contact is closed and the full-load contact is open. As the throttle is moved to the fully open position, the full-load contact closes and the idle contact becomes open. Under cruising conditions with a part-open throttle, both contacts are open. During full-load operation, the ECU provides additional enrichment. During closed throttle operation above a certain rpm (deceleration), the ECU will cut-off fuel injection. Injection will be reintroduced once the rpm returns to idle or the throttle is opened.

ISCV

The ISCV is a solenoid controlled actuator that the ECU uses to automatically control idle speed during normal idle and during engine warm-up. The ISCV is located in a hose that connects the inlet manifold to the air filter side of the throttle plate. When an electrical load, such as headlights or heater fan etc are switched on, the idle speed would tend to drop. The ECU will sense the load and rotate the ISCV against spring tension to increase the air flow through the valve and thus increase the idle speed. When the load is removed, the ECU will pulse the valve so that the air flow is reduced. Normal idle speed should be maintained under all cold and hot operating conditions. If the ISCV fails it will fail in a fail-safe position with the aperture almost closed. This will provide a basic idle speed.

Relays relay

The Motronic electrical system is controlled by a single system relay with dual contacts. A permanent voltage supply is made to relay terminals 30 and 86 from the battery positive terminal. When the ignition is switched on, the ECU earths terminal 85 through ECU terminal number 36 which energises the first relay winding. This causes the first relay contacts to close and terminal 30 is connected to the output circuit at terminal 87. A voltage supply is thus output at terminal 87. Terminal 87 supplies voltage to the injectors, ECU terminal 37, ISCV and the FTVV when fitted. In addition voltage is supplied to the second relay contact. When the ignition is switched on. the ECU briefly earths relay contact 85b at ECU terminal 3. This energises the second relay winding, which closes the second relay contact and connects voltage from terminal 30 to terminal 87b, thereby providing voltage to the fuel pump circuit. After approximately one second, the ECU opens the circuit and the pump stops. This brief running of the fuel pump allows pressure to build within the fuel pressure lines, and provides for an easier start The second circuit will then remain open until the engine is cranked or run. Once the ECU receives a speed signal from the CAS, the second winding will again be energised by the ECU, and the fuel pump will run until the engine is stopped.

Fuel pressure system

A roller type fuel pump, driven by a permanent magnet electric motor mounted close to the fuel tank, draws fuel from the tank and pumps it to the fuel rail via a fuel filter. The pump is of the 'wet' variety in that fuel actually flows through the pump and the electric motor. There is no actual fire risk because the fuel drawn through the pump is not in a combustible condition. Mounted upon the armature shaft is an eccentric rotor holding a number of pockets arranged around the circumference – each pocket containing a metal roller. As the pump is actuated, the rollers are flung outwards by centrifugal force to act as seals. The fuel between the rollers is forced to the pump pressure outlet. Fuel pressure in the fuel rail is maintained at a constant 2.5 bar by a fuel pressure regulator. The fuel pump normally provides much more fuel than is required, and surplus fuel is thus returned to the fuel tank via a return pipe. In fact, a maximum fuel pressure in excess of 5 bar is possible in this system. To prevent pressure loss in the supply system, a non-return valve is provided in the fuel pump outlet. When the ignition is switched off, and the fuel pump ceases operation, pressure is thus maintained for some time.

Fuel pressure regulator

The pressure regulator is fitted on the outlet side of the fuel rail and maintains an even pressure of 2.5 bar in the fuel rail. The pressure regulator consists of two chambers separated by a diaphragm. The upper chamber contains a spring which exerts pressure upon the lower chamber and closes off the outlet diaphragm. Pressurised fuel flows into the lower chamber and this exerts pressure upon the diaphragm. Once the pressure exceeds 2.5 bar, the outlet diaphragm is opened and excess fuel flows back to the fuel tank via a return line. A vacuum hose connects the upper chamber to the inlet manifold so that variations in inlet manifold pressure will not affect the amount of fuel injected. This means that the pressure in the rail is always at a constant pressure above the pressure in the inlet manifold. The quantity of injected fuel thus depends solely on injector opening time, as determined by the ECU, and not on a variable fuel pressure. At idle speed with the vacuum pipe disconnected, or with the engine stopped and the pump running, or at WOT the system fuel pressure will be approximately 2.5 bar. At idle speed (vacuum pipe connected), the fuel pressure will be approximately 0.5 bar under the system pressure.

Self Diagnostic function

The Motronic 1.5 system has a self-test capability that regularly examines the signals from engine sensors and internally logs a code in the event of a fault being present. This code can be extracted from the Motronic serial port by a suitable Fault Code Reader. When the ECU detects that a fault is present, it earths pin 17 and the warning lamp on the dash will light. The lamp will stay lit until the fault is no longer present. If the fault clears, the code will remain logged until wiped clean with a suitable FCR, or until the engine has been started for more than 20 times when the fault code is self initialising. An ECU that retains codes for faults of an intermittent nature is a valuable aid to fault diagnosis. In addition to the self-test capability, Motronic 1.5 has full limp home facilities. In the event of a serious fault in one or more of the sensors, the EMS will substitute a fixed default value in place of the defective sensor. This means that the engine may actually run quite well with failure of one or more minor sensors. Since the substituted values are those of a hot engine, cold starting and running during the warm-up period may be less than satisfactory. Also, failure of a major sensor, ie the AFS, will tend to make driving conditions less easy.

Catalytic Converter and emission control

Versions with a Catalytic Converter will also be fitted with an oxygen sensor so that closed loop control of emissions can be implemented. The OS is heated so that it will reach optimum operating temperature as quickly as possible after the engine is started. The OS heater supply is made from the fuel injection relay terminal number 87b. This ensures that the heater will only operate whilst the engine is running. An FTVV and activated carbon canister are also be employed to aid evaporative emission control. The carbon canister storesfuel vapours until the FTVV is opened by the EMS under certain operating conditions. Once the FTVV is actuated by the EMS,fuel vapours are drawn into the inlet manifold to be burnt by the engine during normal combustion.

Testing

Because of the difficulty in access to many of the sensors, a BOB is deemed necessary to make voltage, resistance, dutycycle and oscilloscope tests.

Motronic 2.5 Copyright Equiptech

[Christ]

hope you get it sorted mate - sure you will....

this is why i fitted carbs

just a thought, fresh petrol in the tank?

[opel2000]

hope you get it sorted mate - sure you will....

this is why i fitted carbs

just a thought, fresh petrol in the tank?

Yes mate, tank had been empty for years, so put a gallon in on Sat, then just to be sure all I hadn't done is wet the bottom of the tank I put another Gallon in yesterday just to be certain.

Getting to the point where I could do with someone over my shoulder checking everything with me and helping me check spark and voltage at pump when cranking and all those stupid things you could do if you were built like an Octopus with 12' tentacles.

But from reading through the above how the "ECU works" post I'm suspecting that the injectors may not be opening due to the ignition/injection relay being a bit on the duff side of things, ideally could do with a replacement to try.

Keep thinking I may have wired things up wrong...... BUT it has ran, only for a short time but it did run, so all should be correct.

Relays relay

The Motronic electrical system is controlled by a single system relay with dual contacts. A permanent voltage supply is made to relay terminals 30 and 86 from the battery positive terminal. When the ignition is switched on, the ECU earths terminal 85 through ECU terminal number 36 which energises the first relay winding. This causes the first relay contacts to close and terminal 30 is connected to the output circuit at terminal 87. A voltage supply is thus output at terminal 87. Terminal 87 supplies voltage to the injectors, ECU terminal 37, ISCV and the FTVV when fitted. In addition voltage is supplied to the second relay contact. When the ignition is switched on. the ECU briefly earths relay contact 85b at ECU terminal 3. This energises the second relay winding, which closes the second relay contact and connects voltage from terminal 30 to terminal 87b, thereby providing voltage to the fuel pump circuit. After approximately one second, the ECU opens the circuit and the pump stops. This brief running of the fuel pump allows pressure to build within the fuel pressure lines, and provides for an easier start The second circuit will then remain open until the engine is cranked or run. Once the ECU receives a speed signal from the CAS, the second winding will again be energised by the ECU, and the fuel pump will run until the engine is stopped.

The bold italic bit is what I suspect is not happening

Edited May 11, 2011 by opel2000

[Devil Fish]

have you actually measured the fuel pressure? Could be injectors working intermittently...

worth an ASNU test/trying a different set? (I've just had this problem on the 400r, I had blues running at the correct 3bar, but only two of them were working properly, the other two were only dribbling intermittently, (and they weren't blocked)).

With the duff injectors, the engine would crank but not fire up.

[Leon]

Clive I did an engine swap on a 205 GTI (1.6 to 1.9) and would it run? Would it hell. In the end I got in such a mess swapping components all over the bloody shop and getting nowhere, gets frustrating and you lose your head a bit.

We know an engine needs 3 things to run - compression, fuel and spark. Even if one of those three is a bit ropey the thing should still have a damn good go at running.

I went right back to basics -

Compression test - even across all cylinders.

Made sure I had at least 3 gallons in the tank. Then I took the fuel line off the injector rail and cranked it to make sure the pump was pumping into the engine bay. It was. Then I put it back on and removed the fuel rail from the engine with the injectors still in it to make sure they were squirting - all ok there so convinced it was fine unless it was overfuelling like a bastard

Checked I had spark at coil - affirmative, good spark. Checked I had spark at each plug - affirmative, good spark. By this stage it was running but very very lumpy so the only thing wrong (other than mechanical damage to a component) was firing order or timing. Turned out despite me having double and triple checked, I had the firing order arse about face. Swapped a couple of leads over and it ran like a dream.

I'm not trying to teach you to suck eggs mate, far from it. I just know how you feel having been in the same place, and you do start looking for niggly little possibilities when sometimes the blind obvious things are what are causing the issue!

Edited May 11, 2011 by Leon

[opel2000]

Thanks Leon and DevilFish

Just tried an alternative ignition relay....... No difference.

Just tried an alternative distribuor....... No difference.

Nothing at all not a pop or bang, just absolute nothing only the sound of the de-compressing unburnt mixture coming from out of the downpipe.

Got good current at Batt due to jump leads from the corsa with it's engine running

Got good compression

Got fuel pressure at the rail

Got spark at the coil and about to grab the neighbour or see if GF can make it outside to check spark at plug.

WELL................. Just what the fuck has happened here I simply haven't got a clue,,,, as there is no spark from the coil whatsoever......... Absolute lightening bolts on saturday, but obviously not long afterwards there must have been nothing at all,,,,,,,,,, GRRRR

[Rab]

Hi Clive,

Mind from a layman! XE

Have good battery

Have good compression

Have good fuel delivery/pump/rail

Have good plugs and spark to all

Have good contact/fuses/camshaft sensor

Which to me if all okay and knowing all are doing what is supposed of each I would then think on what controls all / Brain.

Brain.

Has it managed to get dampness inside / water [i have had one that dispelled a soup spoonfull of water]

Main socket plug: one of the female conectors has got pushed inwards with male conector thus brain not getting full information coming in.

Above just a thought, well awe brickies way owe thinking hope yae git sorted.

cheers rab.

[garymanc]

when mine wouldnt start,it was the dizzy cap and rotor arm were worn also after i changed them i put the leads on wrong was sorted after many hours fecking about

http://www.migweb.co.uk/forums/engines-transmission/388679-c20xe-no-spark.html

[MANTAMAN]

Clive, been down the same road myself, nothing i did would make a simple carb engine run, repeatedly backfired through the intake, i had the head off TEN TIMES! In the end the problem was the carb and the carb i replaced it with, the replacement carb borrowed from a running car but in the process of swapping it i made a choke stick, the original carb had the same problem, but of course to my mind it couldn't be a carb fault as i had put a carb on from a running car and the same problem pessisted, in dessperation i took the car to a classic car garage and they sorted the fault, not before the car cracked its cylinderhead but thats another story!!!

It might be worth it for your sanity to take it to a good, by which i mean a traditional classic sympathetic garage or have a good mobile car electrian look at it. they might not be able to cure your Manta but they would be able to pin point the problem.

Your not far away, it'll soon all fall into place and in a few weeks you'll be drinking beer in the sun at Billing!

[opel2000]

Thanks Fella's

But .... If you had seen my last post onthis topic you would see that after checking the basics again, I have discovered that there is now no spark from the coil.

When I checked the spark from coil on Saturday there was an absolute belting show of sparks, so I knew there was no problem here, plug leads and plugs were all new so should have been no issue here, coupled with the fact that at the time I had no-one to crank engine over whilst holdin plug on lead next to the block.

So there I was assuming the worst, and the bottom line of it is, Coil is stuffed, or lack of power to coil, or the transistors stuffed on the ignition amp module thing the coil sits on.

Will however test the coil later today and if ok will try and source any fault that is not the coil, i.e. bad connection somewhere perhaps.

It might be worth it for your sanity to take it to a good, by which i mean a traditional classic sympathetic garage or have a good mobile car electrian look at it. they might not be able to cure your Manta but they would be able to pin point the problem.

Your not far away, it'll soon all fall into place and in a few weeks you'll be drinking beer in the sun at Billing!

The thing is with having someone else look at it..... They will only do the same job as what I have/will do, Although they may be able to spot things sooner, they would have tested for spark which WAS THERE originally and basically would have spent ages (as I did) suspecting faults elsewhere.

[mickappy]

been a bit of a tw4t this:) did u loose the spark when the relay was changed clive,

that might be knackered?

when youve got the spark back take all the plugs out for a while. these wont start flooded.#

i know im probably telling you how to suck eggs here, but when the plugs are out heat the spark ends up on the gas flame on ur hob b4 you put em back in. then try fire it up. works a treat on these engines. try it mate.