1.9 Gti Idling Issue

[dannydub 3]

I've owned my 205 for 10 years now and 75% of the time it's been stored in the garage with hardly any driving.

 

Since I bought it there has always been an idling issue. Weather hot or cold when I get to a junction and dip the clutch the engine cuts out. I turned the idle up on the car has a temporary fix but as you can imagine when in traffic everything vibrates as it now ticks over at 1500rpm. I've been told it could be leaking air from where the dip stick joins the block?

 

Another issue I have is when I turn left on full lock the engine cuts out. Could this be an earthing issue or connected to the idle problem?

 

I'm currently getting the car prepped for track days and 12 car road rally's but this issues need to be sorted as it's starting to get annoying.

 

Any help is much appreciated

 

Thanks

Edited June 9, 2015 by dannydub

[barny 0]

This is a common issue, google search and forum search 205 gti idle and yee shall find the answers

 

Lots of potential problems from what I can tell, but first job I would do would be clean the throttle body, idle screw, AFM (check the flap is not stuck), intake etc and test the SAD and TPS. I got my mechanic mate to do all of these for me and my similar issue was duly sorted.

[scbond 15 1 Cars]

First step, do an initial setup of the engine (thottle stop, idle air, throttle position etc.). As above, do a search and you will find loads on this sort of thing...there's a lot it can be.

[dannydub 3]

Checked throttle body today and all seems fine. What I have noticed is when I pump the brakes on idle the engine speed increases. Can anyone point me in the right direction of what this could be please?

 

Thanks

[scbond 15 1 Cars]

Air leak on the brake servo somewhere.

[jackherer 543]

I think you'll find it's normal for the idle to be affected by pumping the brakes repeatedly at idle so that's not relevant. As already said do an initial setup of the throttle body etc.

[dannydub 3]

Took the throttle body off yesterday and cleaned it up and all seems fine. We can get the car to idle at 1000rpm when turning the little screw on the throttle body. When I blip the throttle and let off it goes back to 1000rpm no problem. But when I rev the engine over 3000rpm it then drops back to 200rpm, almost cuts out and hunts to find the correct tick over speed of 1000rpm. Am I right in saying the throttle position sensor is faulty which is causing the hunting?

[Tom Fenton 1,526]

Are you adjusting the small screw that moves the butterfly, or the screw which alters the bypass air passage? Does the throttle switch click as soon as you move the butterfly off it's stop?

[dannydub 3]

It was above the butterfly so I assume it was adjusting that. Throttle switch doesn't click so is that up the shoot?

[Tom Fenton 1,526]

Don't assume. If you take it off to properly clean it out including the air bypass drilling then you will see exactly what adjusts what.

[dannydub 3]

I did try to remove it yesterday but couldn't get anything on the bottom 7mm nut. Any suggestions on the best way to remove it??

[scbond 15 1 Cars]

The adjustment of the switch will matter but, having taken one apart, it's highly unlikely it would be faulty as such but rather that the contact inside is poor. I wouldn't do anything like this until you've done as Tom suggested. While it's off I would also suggest testing it with a multimeter.

 

Use a 7mm ring spanner and prepare to scrape your knuckles on the radiator is the only real way I'm afraid. That, or remove it after having removed the throttle body as you have already.

[Tom Fenton 1,526]

To get the throttle body off is a quite straightforward job. I use a 1/4" drive ratchet and extension to get at the bottom nut. A little fiddly maybe but not that hard.

[pug_ham 242 3 Cars]

You don't need to remove the TPS to test it & there's nothing to clean on it, I think Tom is referring to throttle body cleaning off the car & fully removing the idle speed bypass screw to clean the air bypass drilling.

 

It reads to me like you've adjusted the throttle stop screw which could be why the switch no longer clicks away from rest at idle.

 

You should be able to get onto the lower nut with a decent 7mm socket or an open ended spanner.

 

g

[dannydub 3]

This afternoon I removed the throttle body from the car and cleaned it out. Cleaned out the bypass drilling as much as I could. On the bottom of the body there are 4 nipples. 2 for coolant and 2 breathers. The larger breather nipple didn't have a pipe on it. Is there meant to be a pipe on it or is it just a blank which is used for other models?

The idle control does click when I move the butterfly so that's all good.

I put the throttle body back on the car but I still have this hunting issue. Least it's one thing ticked off the list to check

[Tom Fenton 1,526]

Now adjust the butterfly gap when closed open a touch. Ensure the switch still clicks when you open the throttle. Adjust the switch position slightly if needs be to suit the new butterfly gap.

Now adjust the bypass screw in to bring the idle back to spec.

 

Did you remove the bypass screw completely whilst cleaning? If not remove and clean the cone on the end till its spotless.

[dannydub 3]

How do I adjust the butterfly gap? How do I adjust the switch position? I tried removing the bypass screw fully but it won't fully come out. It still spins when you turn it but I couldn't remove from the throttle body completely.

[dannydub 3]

Just spoken to a mate who's explained all that to me which now makes sense.

 

Does anyone know if a pipe should be on the breather nipple under the throttle body?

[Anthony 1,000]

Yes - that should go to the vacuum advance on the dizzy

[dannydub 3]

I have the smaller vacuum pipe going to that