Polo Mk2 Idle cutting out

[bobski1]

Have a mk2 polo with the 1ltr engine with a pierberg 1b3. I have managed to get the car started and it idles for about 5-6 seconds. Unsure why this is happening as there is plenty of fuel supply.

I have minimal experience with carb but am I right in thinking that it's just idle screw adjustment should fix it or could be something else?

I do have a pierberg 2E3 too but unsure how that would fit onto the current manifold and if there are any other adaptions to be made

[Polly Grigora]

Have you checked that the ignition coil isn't losing its supply from the ignition switch?

[steveo3002]

you could have a helper start the car , then mist some carb cleaner into the carb as it starts , if it continues to run when being sprayed that would at least narrow it down to fuel /carb

id take a guess blocked carb jets

did it just happen /ever ran properly

[bobski1]

Polly Grigora said:

Have you checked that the ignition coil isn't losing its supply from the ignition switch?

How would I check this? It starts up absolutely fine its just the 5-6 seconds after it starts the idle dies off to engine off

steveo3002 said:

you could have a helper start the car , then mist some carb cleaner into the carb as it starts , if it continues to run when being sprayed that would at least narrow it down to fuel /carb

id take a guess blocked carb jets

did it just happen /ever ran properly

If I keep jabbing the accelerator it keeps the revs and it keeps alive but 5-6s after it slows and stops. I did take the carb off and clean out what I could see, perhaps I've missed the idle jet, I think it has an idle mixture screw and a speed screw but unsure, there seems to be different types of the pierburg 1B3.

[Huff]

Many years ago we had one of these - the 1.0 breadvan! - brilliant car we should have kept.. anyway:



The Pierberg carb is bolted to a plate on a neck to a plate that mounts to the inlet manifold.
In-between the two, is an integral-moulded rubber isolator that the incoming fuel-air mix flows through, for vibration/thermal insulation.

This damn thing is desperately-prone to cracking with age, the rubber part. Typical early symptom is that the engine dies if you brake hard - a split opens far enough, that the leak = very lean mix = engine dies.

The Pierberg has autochoke, which will run rich-enough to compensate for a /small/ air leak but at present decent ambient temps, will also cut-out in the kind of very short timescale that would match your experience..


So - apart from good ideas already posted: have a good look with a bright light, while pushing the carb in all directions (try that if you keep it running long enough: for a start: with you pressing-down on the carb/aircleaner from above from a start , does the engine stay running... because you have closed-up a gross leak.?

The replacement part is cheap, and very easy to fit. Good luck!

Edited by Huff on Wednesday 25th October 19:05

[Polly Grigora]

bobski1 said:

Polly Grigora said:

Have you checked that the ignition coil isn't losing its supply from the ignition switch?

How would I check this? It starts up absolutely fine its just the 5-6 seconds after it starts the idle dies off to engine off

steveo3002 said:

you could have a helper start the car , then mist some carb cleaner into the carb as it starts , if it continues to run when being sprayed that would at least narrow it down to fuel /carb

id take a guess blocked carb jets

did it just happen /ever ran properly

If I keep jabbing the accelerator it keeps the revs and it keeps alive but 5-6s after it slows and stops. I did take the carb off and clean out what I could see, perhaps I've missed the idle jet, I think it has an idle mixture screw and a speed screw but unsure, there seems to be different types of the pierburg 1B3.

Mmm, although the coil supply can be tested with a voltmeter, the problem does come across as a lack of fuel problem or too much of it

Ignore me apart from - As advised by someone earlier, did you try spraying the neat stuff into the carb intake when the engine was shutting down?

[steveo3002]

5 mins work would prove where the problem lays

air cleaner lid off...and mist (not hose) carb cleaner or easy start into the open carb while someone else works the key , it should run all the time its being being sprayed , might want to spray for 1-2 secs wait and spray again

if it runs as above then its fuel problem , remove the outlet pipe from the pump and direct it into a jar , get a helper to crank the engine , fuel should spurt into the jar , this will confirm theres fuel up as far as the carb

is the filter clean? theyre like 50p

if all this checks out its carb trouble , they dont tend to suffer with ign problems if the cap/arm has been changed when needed

[bobski1]

Ah this I have already done, there is fuel supply into the carb, I took the hose off and it squirts consistently onto a rag

Where do you buy the fuel filter?

Once the fuel is in the carb, does it go through a jet? Entirely possible I missed some when cleaning the carb

[bobski1]

Huff said:

The replacement part is cheap, and very easy to fit. Good luck!

Edited by Huff on Wednesday 25th October 19:05

Where do you get this from please? If it's cheap I'll change it anyway