Running is a mess!

Heya! My golf ran perfectly!

*Ran*

The newest addition to the fleet! : It doesnt want to start when warm.

I have replaced : fuel tank sender, rubber fuel lines, pressure regulator, fuel pump, had all hardlines pressure tested, fuel filter and the entire injection system was professionally rebuilt.

With everything brand new it ran as it should, until about a week ago. Cold start is no problem, but as soon as i go into the Shops and come back after more than 10 seconds im cranking for a solid 10 minute before it sputters to life.

If the engine is warm and i turn it off, and immediatly turn it on again. It runs like it should. But anything longer than about 10 seconds and im cranking away.

The only thing i can think of would be an injector thats "dieseling" and keeps dripping so the mixture cant ignite.

I would very very much appriciate more opinions on what could be causing it.

(P.s. engine has a tendency to run at 800-850 rpm when i come to a stop, havent figured that one out yet either.

Many many thanks!

Have you checked the accumulator?

There's a little screw on the back of it, undo the screw and if fuel comes out it's shot and need replacing.

There's also a non return valve on the fuel pump but if it's a new fuel it should of come with a new valve?

Idle is a little low, it needs to be around 950 to 1000 rpm.
The idle screw is on the back of the throttle body and needs a 7mm spanner to adjust it.

 Accumulator lives next to the fuel pump.



When I remote screw it leaked fuel.


 Even with the screw back in it leaked so a bit of builders silicone sealed it till I found a replacement.



I did have to replace 1 hose as I could not undo it.


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mark1gls said

 Accumulator lives next to the fuel pump.



When I remote screw it leaked fuel.


 Even with the screw back in it leaked so a bit of builders silicone sealed it till I found a replacement.



I did have to replace 1 hose as I could not undo it.


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What a superb explanation sir!

I havent checked the accumulator yet, as a new one has been installed less than 2 months ago. But it woudnt be the first time a new part is bad.

One thing i just noticed, it also takes a really long time to start when cold.

Seen as the car started perfectly when i changed it to the new pump, i think it has a non return valve inside.

I will be checking the accumulator tomorrow and update here. Many many thanks!

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The none return valve is on the end of the main fuel pump underneath the car, it's on the end towards the engine so check that looks new.

https://www.classic-vw.co.uk/fuel-pump-check-valve-for-gti-893906093-13453-p.asp


You could also try and unplug the blue electrical connector on the 5 injector (end of the intake manifold)
This will stop extra fuel being sprayed in when the engine is cold and may help if the injectors are leaking fuel.
I ran with out my 5th for about 12 months before I replaced my injectors.

Info about idle screw and where to find it and check the rubber o ring is in good condition.

View topic: 1800 DX idle low (Update Now Sorted) - The Mk1 Golf Owners Club

mark1gls said

Info about idle screw and where to find it and check the rubber o ring is in good condition.

View topic: 1800 DX idle low (Update Now Sorted) - The Mk1 Golf Owners Club

i just thought about something else, when i had my APK (dutch roadworthy check) the idle was set to 800-950.

The problem was, as soon as i put my clutch in the car died, i turned it up to about 1100. and it doesnt die anymore.

just checked the fuel pump i ordered, it has the non return valve so that should be good.

I run mine at 1000 rpm as things start to rattle if it's any lower, maybe try yours at 1000rpm?

mark1gls said

I run mine at 1000 rpm as things start to rattle if it's any lower, maybe try yours at 1000rpm?

i have a creeping suspicion my idle screw is turning itself out. will check the seal also.

ill try it at 1000. do you set the idle with or without headlights? my rpm drops a fair bit with them on

Yes a new rubber o ring on the idle screw should stop the screw from moving and also stop any air leaks.

mark1gls said

Yes a new rubber o ring on the idle screw should stop the screw from moving and also stop any air leaks.

Hello! Me again,

I just checked the pressure regulator by taking out the screw. Absolutely dry as can be! And the fuel pump 100% has a non return valve.

Idle o-ring is a bit worn but not leaking. I turned it up to 1050 without lights on. Runs okay again, starting however is still a bit off sometimes. It starts 2/10x now but the remainders im turning for a good 5-10min

Also, it smells like fuel. no leaks that i can see underneath the car / in engine bay

when i turn the key(either hot or cold), it starts. Runs for about 1-2 seconds then dies. if i go full throttle in that timeframe, it stays running. If i dont, im turning for 10 mins.

i suspect this info might help some more!

many many thanks in advance!

It could be the injectors are not holding pressure and dribbling fuel, take the plugs out when you have turned it over for a bit and see if they're wet with petrol.

cedar said

It could be the injectors are not holding pressure and dribbling fuel, take the plugs out when you have turned it over for a bit and see if they're wet with petrol.

On a very tired evening i pulled the plugs instead of the injectors, they are *wet* mostly oil tho.

Engine has 613k km under its belt.

Will pull the injectors shortly

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I meant the spark plugs, not the injectors, if the plugs are wet and smell of petrol then the injectors are more than likely your problem.
You could try some injector cleaner in the petrol and you can have them cleaned but I'm not sure of the cost.

cedar said

I meant the spark plugs, not the injectors, if the plugs are wet and smell of petrol then the injectors are more than likely your problem.
You could try some injector cleaner in the petrol and you can have them cleaned but I'm not sure of the cost.

Im not fully sure if they were wet of fuel or oil, im taking them out later today and ill Update here.

What else could i check?

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I think that if there was enough oil to coat the plugs you would get a lot of blue smoke on start up, you wouldn't miss it.
I've just re- read your first post, could you ask whoever rebuilt the injection system about the injectors.

cedar said

I think that if there was enough oil to coat the plugs you would get a lot of blue smoke on start up, you wouldn't miss it.
I've just re- read your first post, could you ask whoever rebuilt the injection system about the injectors.

The injectors werent touched, 1 3 and 4 woudnt come out for dear life.

Warm up relay and plungersystem were fully rebuilt.

No real blue smoke on start, a very little hazyness thats gone after a few seconds.


Update : starting takes about 4 turns now and starts relatively "okay" . If i turn the key to on and leave it there it wont start. If i go from 0 to turning the starter it starts.




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It's logical that leaving the ignition on for 4 secs is priming the system and that increased pressure is forcing enough fuel through the injectors that added to what was there before is flooding the engine.

It's only a guess.

cedar said

It's logical that leaving the ignition on for 4 secs is priming the system and that increased pressure is forcing enough fuel through the injectors that added to what was there before is flooding the engine.

It's only a guess.

So, i just did a bunch.

Took out the plugs, wet ish. But not from fuel, just build up of oil over the past few years. Nothing major.

Did absolutely precisely nothing to the plugs.

Reinstalled them as they were seated.


Took out the injectors(absolutely pain in the ass). No real sign of leakage/dripping after.

For whatever reason i can now leave the key on the on position for as long as i want. It will start every single time if i throttle a bit.

It has started to run on 3 cilinders but thats because the injector on cil2 has a fubar'd o-ring. New ones on the way.

It does smell like fuel when it starts. Not for long but there is a smell every single time.

Shoudnt an injection car start without throttle?

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I would take the time to read Tolusina's guide on cleaning the Injectors to make sure they have good vaporization of fuel while you have them out.

CIS Injector Cleaning, Seal and Holder Replacement