Idle problem

[Novice in need]

Hi Shaudon

Theres so much to try its ridiculous... iv just looked to make certain that my mixer screw was not missing as another member has reported stalling idle probs and this seems in his case the culprit.

The leads im gona try sorting tomorrow.... what i was getting at with the spark plugs was... if you look at the ends that the leads attach to there is the metal tips fitted (hope you are with me so far lol). Well on mine these tips have been removed as they just screw off, this has left just the thread and that is what the leads are pushed onto ....

So il try sorting this puzzle out then also i am ging to check for water in petrol tank and any leaks from petrol expansion tank etc

Then if all fails its back on here to try and gain some mre ideas on what to try

[john1]

Hi Shaudon

Theres so much to try its ridiculous... iv just looked to make certain that my mixer screw was not missing as another member has reported stalling idle probs and this seems in his case the culprit.

The leads im gona try sorting tomorrow.... what i was getting at with the spark plugs was... if you look at the ends that the leads attach to there is the metal tips fitted (hope you are with me so far lol). Well on mine these tips have been removed as they just screw off, this has left just the thread and that is what the leads are pushed onto ....

So il try sorting this puzzle out then also i am ging to check for water in petrol tank and any leaks from petrol expansion tank etc

Then if all fails its back on here to try and gain some mre ideas on what to try

The end of you plug should come off mate thats normal.

Set timming?
have you tried to turn the idle up?

[T25Convert]

Hi,

If the problem only happens after the choke has switched off, then this suggests that the problem is related to mixture as Kev suggested.

When the choke is on your mixture is much stronger (i.e. a much high ratio of fuel to air). Once the choke comes off the mixture weakens (i.e. the ration of fuel to air decreases).

If something further weakens this mixture then it may become so weak that the engine just gives up. It happens at idle, as at this time the carb is only drawing very small amounts of air and fuel through, so its much more sensitive to relatively small changes in fuel or air mix.

So things that would weaken your mixture:

1) air leaks, allowing more air in after the carb has done its job of carefully metering out enough fuel. Prime suspects are the gasket that the carb joins to the mainfold on, and the brake vacuum hose (off the left manifold).

2) low fuel flow - prime suspects are crap in the line, crap in the filter or a knackered pump. However, low fuel flow would also normally cause really rough running at higher revs as well, so less likely to be this.

I'd put money on it being the brake servo hose as identfied by Kev in another of your posts - you still have the braided one on there, which is likley to be knackered after all these years. Its cheap to change before you start messing with any more exepensive bits. Found on mine spraying it made no difference, as the whole length was porous.

Tkae it off, put your thumb over the end and suck - you'll soon know if its leaking (mind the wire reinforcement though!)

Good luck,

Cheers,

Alex.

[Shaundon]

Ive allready changed the fuel filter under van and cleaned the small one inside the fuel inlet on the carb as well as testing the pipe all the way back to the tank so i'm sure its not that. Replaced the fuel pump push rod too as that was a little worn. Think the pumps ok as squirts fuel ok when hand pumping while off. I guess if its a fuel delivery problem after it stalls i could take the top of the carb and see if enough fuel in the float bowl?

I'll double check for air leaks this weekend as it's sounding most likely at moment. The base of the carb gasket looked fine and has recently been replaced so most likely that brake hose.

if it is a weak mixture will i be able to tell anything from inspecting the spark plugs after it has stalled?

[kevtherev]

no

[Shaundon]

Ok checked the brake servo hose by taking off and sucking / blowing through it and no sign of any leaks. Checked all other areas for leaks by spraying carb cleaner round and no noticable change in idle. Only way i could be more sure of no air leaks would be to blow smoke into carb under pressure and see where it escapes?

By turning up the idle speed scew i can stop her from stalling but she runs at say 850rpm at idle for about 5 seconds then speeds up to above 1000 rpm for a few seconds before going back down again. Pulling away from junctions she hesitates and going up hill she can loose power where droping a gear has no affect.

took the dizzy head off and inspected it and there are black deposits on the contact points (see pic
https://gdux7q.bay.livefilestore.com/y1 ... jpg?psid=1).

Could this be causing the problem?

[Shaundon]

Ok from what i've read elsewhere the dizzy cap isn't the issue!?

However on trying to check the timing the haynes manual says to disconect the vac advance, on doing this the engine cuts out instantly! Cannot get it to run without the vac advanve connected.! This doesnt seem right to me, anyone got any suggestions as to why this would be?

[kevtherev]

turn up the idle speed until it does?

[Shaundon]

Tested the timing with a strobe light from halfords and found the the engine cuts out without the vac advance as it becomes retarded without it. So advanced the timing enough to keep it ticking over without the vac advance and took her out for a spin. Seems to run much better, no more hesitation and loss of power, best shes run since i got her! Not counting chickens yet though as still got irregular idle and have to keep idle speed screw turned in to stop her stalling at junctions but much better running off idle.

What i need is someone with a good running dg that would be willing to let me swap a few bits onto my bus for a bit to see if improves her symptomns. Any takers???

[kevtherev]

Did you line up the marks as per Haynes when the distributor was moved?.

[alanf_uk2002]

I have experienced similar problems and I diagnosed it as crap in the carb (Pierburg 2E on 1.9DG) and having rebuilt it over the weekend I can quite happily say that it was definately the carb! I had previously changed the fuel filters and even removed the filter in the inlet of the carb but it made no difference to the rough running and stalling. Today it runs as sweet as a nut, a different van completely. Worth doing if you haven't already done it.

Good luck.
Alan

[Shaundon]

Never lined up as per manual as the mark on this engine is 5 degrees after tdc and ive read elsewhere that that is for a dizzy with 2 vac lines. With one vac line it's 5 to 8 degrees before tdc ?

Also i had to wind the idle screw in so much to stop it stalling that the centrifugal advance is starting to take effect so hard to set the base advance in this case. In the end just advanced it enough to stop it stalling without the vac advance connected.

Still suspect the carb is a problem as alan says but ive had it apart and cleaned it up as much as i can and not sure what more to do about it. Bromyard vw do a rebuild service but its 190 quid which seems alot if i don't know for sure it will work.

[Novice in need]

Hi Shaundon sorry to hear that you are still at it....

I believe that the prob is the carb and as such after all the work and checks carried out on mine (whilst i found lots of other stuff ie air leaks, perished vac pipes etc) i have sent mine off to Bromyards! The guy Roger seems like a good sort and whilst £190 is a sting in the back pocket im hoping that once it is cleaned and checked for worn parts blocked or partially blocked jets, worn diaphrams and multiple other potential probs by someone who knows what they are doing and then setting it up properly rather than my a complete NOVICE IN NEED it will resolve the intermittent stalling ?

Il let you know the outcome

[Novice in need]

Thanks John 1 ... glad to clear that 1 up

[Shaundon]

Hi novice,

please let me know how it goes with the cleaned up carb, if it works for u i may go down that road too.

S