AAZ with hanging idle

[95gltd]

Hey guys,

Anyone ever had a AAZ with a hanging idle ? Linkage is all free. Whats odd is that it doesn't seem to hang untill I've had it on the road for 10 minutes. It will hang at 1600 rpm. Here is the kicker pull out the timing advance handle and it will bring the idle down close to 1000 ?? push the handle back in and it goes right back up.

Has me stumped. When the engine is warmed up it idles at 1000 that is when it does not hang.

Pump and injectors were rebuilt less than 2 years ago maybe 50k Kms on them.

I noticed the idle was too low once i advanced the pump before winter. Kind of lived with it, but hot it would idle maybe 750-800. Dead cold it would idle at 500. Adjusted the idle up with the idle screw. Now i get the hanging sometimes.

[95gltd]

Bump

Also i noticed that the hang is worse the colder the outside temperature is.

[95gltd]

Ok so the advance handle does not always bring it down and the hanging is intermittent. Definately gets worse the colder the temp is.

Searched and found 1 threde where a guy had an injector problem. My problem seems to be only since cold weather and me fooling with the idle screw. When it does not hang the idle is steady at 1000 rpm.

[burn_your_money]

AC or non AC? or, vacuum actuated fast idle or mechanical?

[95gltd]

Its an A/C car 95 golf GL with the original 1.9 aaz if that helps.

In the 4 years I've had it there hasn't been a fast idle :S
I'm assuming there should be a plunger type actuator for the fast idle somewhere similar to the old 6.2L gm diesel ?

Only IP pump i have any knowlege of is the cummins P pump and older 6.2 gm's. VW i'm kind of clueless.



Only problem i ever had with it was the pump a couple years ago. Had TinTin rebuild it. I initially thought it was injectors, so had those rebuilt first. Pump and injectors less than 50,000 km.


I went out tonight and checked under the hood when the idle was stuck. The cable is loose, but if you tug on the throttle arm on the pum it will back off ever so slightly which will bring the idle back to normal. Shaft looks like a bunch of springs. None look rusty, sprayed with WD-40 and no change.
Thanks

[burn_your_money]

On the drivers side of the pump at the top there should be a black vacuum pod. That is what controls the fast idle. It's attached to a lever that is spring loaded. Maybe something has run amok with that lever.

[95gltd]

On the drivers side of the pump at the top there should be a black vacuum pod. That is what controls the fast idle. It's attached to a lever that is spring loaded. Maybe something has run amok with that lever.

Hmm didn't notice anything like that when I was under the hood. Seems odd that when its dead cold it does not do this. Once you drive it for about 10 minutes then it sticks. If you push back on the throttle arm you can see it slightly move back and the idle goes down. As soon as you let go it goes back, yet the throttle cable is loose and not binding. Its like it needs a return spring as on carb motor.

[rabbitman]

Try to find if it's an internal or external problem.

[Rabbit on Roids]

it probably has a worn throttle shaft bushing.

[burn_your_money]

Can you take a picture of the back of the pump?

[orengutan]

Interesting. I have a very, very similar problem, but I can't remember if this happened before or after I had a cold start valve failure (probably not relevant, but thats when I noticed this).

my car will usually start anywhere between 1000-1100 idle, and often as it gets warm it'll "float" down to around 950.

cold start handle doesnt have any effect on this number.

I read the bosch pump manual, but it never mentions anything about a cold start handle+vacuum in AC models, so I'm a little confused there.