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Varajet II GT/J 1.8 possible not allowing fuel to be taken from pump


discodas72
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Hi All

 

Just a query I've replaced the fuel pump but unsure why still no fuel being sent to carburettor. Tried the original thick washer off AC pump and the new paper one in various computations no fuel out. But when its not tightened up I can push fuel through?? Also is it easy to gain access to float chamber to check if its stuck? Novice mechanic 😆 

 

Darryl

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hi. there. if i remember correctly the 1.8 has a supply line from the tank and also a return line too.( i may be wrong 2.0 versions dont have this )

obviously if it worked before then the pipes must be in the right place so what i would do is ......

check that the supply pipe from tank is clear .if you blow in it you should hear bubbling in the tank.

connect this to the fuel pump inlet and with a pipe connected to the outlet and safe in a jar you should be able to manually pump the fuel through with the pump in your hand. in a lot of cases the pump will work fine on the car either with or without the spacer but if you have it then i would fit it as it also can help as a heat shield too.

so if it works manually but not on the car this would suggest either    wrong pump ? or camshaft lobe worn down. ( you should be able to see this through the hole )

lets start with the sbove and seewhat you find.

hope this is a little help to you

as regards float chamber most varijets have a gauze top above the chamber that you can visually see into.

 

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1.8 only has supply. Only Injection has fuel return

you might need to look into the hole where pump fits as it has a cam that drives the fuel pump, make sure that has not ground to nothing. Failing that, you can remove just the top cam box cover on the 1.8 to see the camshaft, this will let you see the fuel pump running on the camshaft lobe when turning engine over (don't start the car though, just remove the coil HT lead to no spark or something) as it dies flick oil about if it's runs high rpm. Keep fingers out the box when turning engine over !!

Edited by Jessopia74
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There should be one thick spacer and a paper gasket either side. Easy enough to take off and push the piston in enough to check it works by hand. But like above, if all that’s ok check for blockages. Also, check you have fuel in the tank, as it’s possible your voltage regulator may be giving false tank reading. 

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Hi Thanks image is what our old one looked like. 

As its been stored I've disconnected the tank fuel line. As I use a small temporary tank in the engine bay. So save evaporation or water ingress. Its been fine up until it was not started for quite a while.

I've had fuel pumping by hand but not once in place and tightened up. 

Going to look at float chamber to see if its stuck. 

Query is it common for AC pumps to seize up??

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if the fuel pumps by hand but not when on the engine it cant be anything to do with the carb. 

unless you are 100% sure of this .( ie no fuel comes out of the pump when its bolted onto engine and your cranking ? )

check camshaft lobe for wear.

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4 hours ago, ®evo03 said:

Can you test pump once connected to block, though the 1.8 was driven mounted to block? Not head? May be wrong.

Disconnect inlet to carb, and 500ml pop bottle, should show, with a few cranks. 

 

It's in the pic above mate, runs off the camshaft just behind the oil filler cap , in front of the carb.

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Hi All im popping down later to make a start with all your suggestions 

 

Thank you all 

Hi 

 

Well cam lobe if fine. pump rotation is good. Pump piston moves what appears to be sufficient. Fuel is appearing in feed to carb don't know if its enough??. Float is not stuck. Tries to start runs for 30s or so then dies. Runs better when syringed Fuel in float carb chamber. Will removed plugs and replace now. That might help is starting 😔😔

Might be choked up? 

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so  :  it is actually pumping fuel now ? what did you do now differently ?

a few more questions ideas.......

is the fuel that you are now using from tank fairly new.?   old fuel does go off eventually .

if there is sufficient flow and float chamber is filling up then valve is ok. 

will it run at higher revs and only dies at idle ?( blocked carb idle jet/ passage.)

or does it stall at any speed ? ( check main jet needle is free.should press down and spring return.)

by what means have you checked carb.   visually,   through acess plate ?   or top off completely ? 

 

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Took of top check the lobe and pump piston turned over and monitored the piston movement. Replaced the pump with original washers cork thick one 5mm. Pumped by hand to prim pump. Fuel seen from pipe to carb float connection. Refit and tighten. Took of gauze bit and looked inside. Small spring thing moves up and down. Prime chamber by syringe fuel. 

Fuel is via a small temporary remote tank container in engine bay. Fresh vpower.

Only fires with no throttle and any depression of throttle it dies.

It did run at slightly higher revs when syringe fuel into carb. 

I might recheck the fuel out of pump again to see how much pressure it's doing or pumping by hand its was quite a flow.

Puzzled 

 

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if i remember correctly there is a fuel filter inside the main carb fuel inlet nut. worth checking that its not bunged up. 

once you know that is ok and float chamber is filling up correctly then it sounds like a blocked carb passage. 

also remember that if the air filter housing  is removed then you will have an additional air leak due to the vacuum hose for the hot/ cold flap.but that should make a poor idle not a revving issue

and as i mentioned.make sure the main jet needle is free to push and return

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Took of top check the lobe and pump piston turned over and monitored the piston movement. Replaced the pump with original washers cork thick one 5mm. Pumped by hand to prim pump. Fuel seen from pipe to carb float connection. Refit and tighten. Took of gauze bit and looked inside. Small spring thing moves up and down. Prime chamber by syringe fuel. 

Fuel is via a small temporary remote tank container in engine bay. Fresh vpower.

Only fires with no throttle and any depression of throttle it dies.

It did run at slightly higher revs when syringe fuel into carb. 

I might recheck the fuel out of pump again to see how much pressure it's doing or pumping by hand its was quite a flow.

Puzzled 

 

Super will crack it off and look.

Will crack that off as well. Are the jets easy to view check?

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the springy arm that you checked in the carb moves a tapered needle into and out of the main jet to vary the mixture under various load/ vacuum conditions. so it sounds like that is ok.   i doubt that you will see anything else even if the float chamber is full of debris because the float and cover pretty much hides anything under it !

to check anything else inside requires removing the top of the carb and you will need a new gasket as the old one will no doubt tear if its not been touched for years.

see what the inlet filter is like first as you are eliminating things bit by bit now.

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  • 1 month later...

Hi Everyone 

Sorry late reply update.

 

I've done a few more checks.

Checked the filter inlet to carb? Did not see any blockages or rubbish. Removed top of carb. To an alien like me looked ok. Float thing pushed freely. I've now got fuel pumping via pump now altered the washers to maintain clearance.

Replace everything started eventually but now wont idle.

 

If you keep revs up above 2000 rpm its ok got up to temp. But as soon as you lift off even gradually down it just dies. Had a misfire due to broken rotor arm. Sorted that.

Choke appears to be fine. Also odd thing the amp gauge has stopped showing battery charge. It used to move before but now remains stationery in the yellow. Might not be connected.

 

Tried adjusting he idle screw but nothing.

 

Any thoughts is there an idle jet that could be restricted block would carb cleaner injection cleaner work?

Thank you in advance for your help 😊 😁

Darryl

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you can get a blocked idle passage. pretty sure the varijet doesnt have an idle jet as such. mine did it a while ago.it would do everything correct except revs fell off at idle.

i managed to clear mine simply by revving it and placing my hand over the intake.this seemed to suck it clear but a more technical ( and precise) way would be to remove the two adjustment screws ( counting the turns from fully in) and with the top removed using carb cleaner and an airline to blow through the passages. BUT do not loose the check valve ball bearings from the orifices. (see haynes manual)

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Super for a complete  novice you say intake do you mean the two main inlet air intake Chambers? 

 

In the chamber with tge choke valve there is a brass pipe with small hole is that the jet a blow onto?

Did not know there were two adjusters just tried he one on the throttle linkage 

 

Sorry to asking simple questions 

 

Darryl

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hi. no dont adjust the one on the linkage unless you know someone has been playing with it otherwise you may affect the distributor vacuum advance .

the varijet has 2 adjustment screws on it. one is a basic bypass system which sets the idle speed(providing the throttle stop screw is correct)and the other smaller one sets the idle mixture.if the car was running ok before then these screws should be in the correct place and need to be counted from fully in if you intend removing them.

yes it is a little complicated if youre not familiar with the varijet. lots of people throw them away and replace them with something else which is a shame realy cos they are a good carb when set up correctly.

the ball bearings are inside the drillings/ cavaties .one is below the accelerator pump and the other near the top. if you have a haynes book it does show them .if it were me i would try just revving the engine and then blocking the airflow as the revs fall.this worked for mine when i had similar symptoms to you.

obviously other things can be wrong that would cause poor running/ idle such as timing,plug gaps/ condition,air leaks( especially brake servohose) and its worth making sure everything else is in good order too before blaming the carb.

hope this helps a little .pity you are not nearby !

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