Gte Engine Idle Problems

[73 manta a]

Hi, i have recently transplanted a gte engine and injection system into my manta a and cannot get it to idle and it misses when revved. I have taken the plugs out and they are very black and wet after the engine has run, so i suspect over fueling. I've changed a temp sensor as it was reading 0 ohms and thought that would cure it but no luck.

Any1 have any ideas? Thanks

[Snowy]

Hi, i have recently transplanted a gte engine and injection system into my manta a and cannot get it to idle and it misses when revved. I have taken the plugs out and they are very black and wet after the engine has run, so i suspect over fueling. I've changed a temp sensor as it was reading 0 ohms and thought that would cure it but no luck.

Any1 have any ideas? Thanks

Did you have the engine running in its current state in the doner manta?

Or did you transplate a mix and match of parts that you haven't had runnning together?

Is everything standard GTE? I.e. fuel pump etc??

Thanks

[73 manta a]

Hi, i bought the engine and ascociated parts from a running car so i was told but never saw it actually run. As far as i no all the parts are standard except the fuel pump but that was brand new and is the right pressure. I also had to install a swirl pot as the car still has a carb tank. I tried running the engine agian today and it was the same but once i got it warm it started to idle although it was quite high rpm but the rev counter was reading about 700 rpm. Then let it cool and it was the same as before even when hot again.

really is a mystery to me as i usually deal with carbs lol. Thanks

[pat]

is it possible the pressure regulator on the fuel rail is knackered and allowing it to overfuel ?

alternatively you could also unplug the cold start injector to see if its fueling too much via that maybe

Edited January 16, 2010 by pat

[mantadoc]

What Pat said.

Also need more description on not idling, as in can you start it with your foot down on the throttle only?

Does it only run if revved and die when throttle closed?

Does the exhaust stink of fuel when running?

Were you very sure to put the connectors on the thermostat housing in the correct places?

[73 manta a]

What Pat said.

Also need more description on not idling, as in can you start it with your foot down on the throttle only?

Does it only run if revved and die when throttle closed?

Does the exhaust stink of fuel when running?

Were you very sure to put the connectors on the thermostat housing in the correct places?

HI, yes the only way it starts is with a open throttle, as soon as i take my foot off it coughs and splutters then dies. The exhaust doesnt smell overly rich when running but not really sure how rich the injected engines run? After the engine dies there is a strong smell of fuel from the exhaust. The loom was on the inlet when i bought it and i got a spare with it and the plugs are in the same position on both. What is the resistance on the two temp sensors?

Thanks for your reply

is it possible the pressure regulator on the fuel rail is knackered and allowing it to overfuel ?

alternatively you could also unplug the cold start injector to see if its fueling too much via that maybe

Hi, ive tried unplugging the 5th injector and its still the same, i do have a spare regulator that i can try.

Thanks

[mantadoc]

You have choices, test components logically or wait for people to suggest bizarres tuff as everyone (me included) will have come across a bizarre fix for an unusual situation. These things are best investigated when everything else is eliminated.

Basic assumptions before working on injection:

Static timing is correct (also consider setting timing by maximum advance)

Plugs, leads, dizzy cap, rotor arm and dizzy in good order.

Good spark (tested however you like)

And the following specifically for engines recently pulled to pieces / transplanted:

Make sure the fuel PRESSURE FEED goes to the T PIECE and NOT to the regulator. The regulator is connected to the return line.

(Also your swirl pot should have some sort of overflow or return to the tank. Just in case the whole loop is getting pressurised. Very unlikely but I digress)

After that get a Haynes manual and / or download one of the Jetronic guides that covers extensive testing (such as the Alfa one) and substitute Manta values where applicable.

However, note the following:

A Manta can run with the following disconnected:

Throttle switch (it isn't a potentiometer)

Cold start injector

Air flow meter - It can idle only, as soon as you touch throttle it will stall

If it were mine I would do all three of the above and clamp the auxiliary air valve flexible hose shut (the pipe that goes through the lumpy thing on top of the thermostat housing) and see if it idles.

That eliminates most of the cold start stuff and wearing components.

However, that is if it was mine but it isn't mine and I wouldn't recomment anyone do this.

[73 manta a]

You have choices, test components logically or wait for people to suggest bizarres tuff as everyone (me included) will have come across a bizarre fix for an unusual situation. These things are best investigated when everything else is eliminated.

Basic assumptions before working on injection:

Static timing is correct (also consider setting timing by maximum advance)

Plugs, leads, dizzy cap, rotor arm and dizzy in good order.

Good spark (tested however you like)

And the following specifically for engines recently pulled to pieces / transplanted:

Make sure the fuel PRESSURE FEED goes to the T PIECE and NOT to the regulator. The regulator is connected to the return line.

(Also your swirl pot should have some sort of overflow or return to the tank. Just in case the whole loop is getting pressurised. Very unlikely but I digress)

After that get a Haynes manual and / or download one of the Jetronic guides that covers extensive testing (such as the Alfa one) and substitute Manta values where applicable.

However, note the following:

A Manta can run with the following disconnected:

Throttle switch (it isn't a potentiometer)

Cold start injector

Air flow meter - It can idle only, as soon as you touch throttle it will stall

If it were mine I would do all three of the above and clamp the auxiliary air valve flexible hose shut (the pipe that goes through the lumpy thing on top of the thermostat housing) and see if it idles.

That eliminates most of the cold start stuff and wearing components.

However, that is if it was mine but it isn't mine and I wouldn't recomment anyone do this.

Hi, the fuel pipework is all correct and ive checked the ignition components and all is good. I have swapped the air valve over from the other manifold as the resistance readings i got between the two were very different but that didnt help, also tried running it without the cold start injector connected and the airflow meter but still wouldnt idle.

Its a mystery! Thanks for your suggestions

[Snowy]

Simple question, have you tried setting up the mixture properly? If someone has played around with the settings, including the butterfly you'll have the problems you describe.

I would also be looking for air leaks.

[mantadoc]

All the air valve does is bypass the throttle butterfly to allow more air into the manifold to compliment the extra fuel from the cold start injector.

These are open when cold (take both pipes off you can see through them) and close when power is applied over s short time. If you can see through it you can check its operation by watching it from cold with ignition on to see if it closes. Running car not required. However clamping the pipe off eliminates it totally. You don't need to know if it "works" that way. Symptoms from one wedged open are idle climbs higher and higher as car warms up to around 1500 / 2000 rpm

If the airflow meter wires are disconnected it won't run above idle.

Be very sure about the fuel feed thing, it's common mistake even for folk working on Mantas for years.

Make sure the injection earth is secure on the back of the plenum chamber and that the ring terminal on the starter from the injection look is clean and secure both under the bolt and the wire into the terminal.

These injection systems are basically clockwork, 90% of the complexity is the cold start stuff. Fuel pressure is one of the biggest factors, as barring temp sensor that and the AFM are the biggest effect on fuelling oh yeah and ECU.

[73 manta a]

Simple question, have you tried setting up the mixture properly? If someone has played around with the settings, including the butterfly you'll have the problems you describe.

I would also be looking for air leaks.

How do you set up the mixture? i didnt think it was adjustabe. I might try squirting some wd around the manifold and see if that helps.

Thanks

[mantadoc]

How do you set up the mixture? i didnt think it was adjustabe. I might try squirting some wd around the manifold and see if that helps.

Thanks

adjustable via the clearance in the butterfly AND the allen key or whatever under a black plug in the top of the alloy of the AFM.

However as before disconnection can eliminate AFM.

Also there may be a bypass screw in the throttle body, I forget

[73 manta a]

adjustable via the clearance in the butterfly AND the allen key or whatever under a black plug in the top of the alloy of the AFM.

However as before disconnection can eliminate AFM.

Also there may be a bypass screw in the throttle body, I forget

Thanks for everyones help. I will have another go at it either tomorrow or monday and see if i cant get to the bottom of this!

[mantadoc]

Thanks for everyones help. I will have another go at it either tomorrow or monday and see if i cant get to the bottom of this!

Those adjusters are supposed to have caps on and not be touched. In all probability unless everything else is checked altering them will make it worse instead of better.

[Snowy]

Those adjusters are supposed to have caps on and not be touched. In all probability unless everything else is checked altering them will make it worse instead of better.

I will be impressed if there are still caps on them now.

The butterfly has to be set correctly, instructions in the haynes manual. Do not use the butterfly adjuster to try and set the idle. There is a seperate adjuster for this.

The mixture screw should only be adjusted if you have the correct equipment to measure the gases.

I would still be checking all the pipework, inlet manifold etc for an air leak.

Edited January 16, 2010 by Snowy

[cam.in.head]

dont forget the haynes manual shows pipework the WRONG WAY ROUND ! just in case you followed this when fitting .

[mantadoc]

dont forget the haynes manual shows pipework the WRONG WAY ROUND ! just in case you followed this when fitting .

What page? Never noticed

[moodoo]

Had a similar problem with my A-series last year (she has an injected 1.9 engine). She wouldn't start, or would barely start but not idle. Turned out to be the temp sensor...you say you've changed it, but anyway, what I found at the time was when cold you should have 8-12kohm, warm 2-3kohm, and hot, 250-400ohm. Prob not much help, but you never know.

When I was hunting that problem, I was continually told to check all the grounding points. If you've transplanted the engine, possibly some of the new earths are not making proper contact?

(My car had been fitted with LE jetronic, rather than L, but I think there's very little difference between.)

[73 manta a]

Had a similar problem with my A-series last year (she has an injected 1.9 engine). She wouldn't start, or would barely start but not idle. Turned out to be the temp sensor...you say you've changed it, but anyway, what I found at the time was when cold you should have 8-12kohm, warm 2-3kohm, and hot, 250-400ohm. Prob not much help, but you never know.

When I was hunting that problem, I was continually told to check all the grounding points. If you've transplanted the engine, possibly some of the new earths are not making proper contact?

(My car had been fitted with LE jetronic, rather than L, but I think there's very little difference between.)

Hi, i may try a new sensor then just to see if it cures it. The resistance readings u've given are alot different to mine so could b the problem. I think my car is also le.

Thanks

[cam.in.head]

What page? Never noticed

its at the back where it shows the injection pipework layout. fuel pumped from the tank should go to the T PIECE .return fuel then comes from the centre pipe of the pressure reg back to the tank.

also with regards the temp sensor .there are two types. the gte 2 litre one has one element in it that will give a reading accross the terminals but not to earth.the other type as fitted to 2.2 engine & senator 2.5/3.0 has two seperate elements in it that give readings to earth. i seem to think they are similar in fitting but not electrically interchangeable.