Idle Too High

[soeima 0]

Hi there friends,

 

I know that this topic is all over the place and I even got the Haynes book to help me with it.

But the problem is that there is a lot of information about Idle issues on this engine and I believe mine is different from everyone elses.

The car starts up fine and Idles at around 1K rpm.

When hot, goes up to 2.1K and stays there everytime I stop or press the clutch.

Although, if i'm stopped and force the RPM above 3K and let it get back down, it will stay at 1K until I move again.

 

Can you guys give me a guideline to fix this?

 

Thanks a million.

 

[Tom Fenton 1,542]

I'd start with the basics, the idle can only increase if the engine is getting more air flow.

 

From your description it sounds to me like the throttle disc, linkage or cable is sticky and not returning properly. That is where I would start looking anyway.

[soeima 0]

I'd start with the basics, the idle can only increase if the engine is getting more air flow.

 

From your description it sounds to me like the throttle disc, linkage or cable is sticky and not returning properly. That is where I would start looking anyway.

 

Thank you Tom! That's a good starting point, before messing around with air and mixture bolts I guess.

Will give it a good look and will share some pictures for a closer look.

[Thijs_Rallye 87 4 Cars]

Check if the butterfly valve (throttle) doesn't stick and if the contacts switch when they are supposed to.

[soeima 0]

Check if the butterfly valve (throttle) doesn't stick and if the contacts switch when they are supposed to.

 

How can I check? Safe to open it up to check?

[Thijs_Rallye 87 4 Cars]

Take the hose off and look how much gunk has accumulated around the closing edges. If it is very dirty it might be worth it to take the whole throttlebody off and clean it, which will surely lead to re-setting the idle speed usually.

 

Contacts can be checked with a multi meter on the TPS contacts.

[soeima 0]

Hi guys!

Check a bunch of stuff today.

Everything looks clean and I ended up messing with the throttle screw and air intake screw.

Did not touch the mixture one tho.

 

The result was a better idle (around 1k) and gets up to 1.5. Since before was 1.5 min going to 2/2.1, we have an improvement.

Also realized that if the idle goes up ton1.5 Atm and if I give a little kick on the throttle, it goes back to 1K.

If I start pushing the throttle slowly to 1.5, the idle then keeps that value. Only comes back down with the magic and fast kick on the pedal.

 

It's better, but it's still a strange behaviour. Anyone had some of this symptoms?

 

Cheers

[Tom Fenton 1,542]

If I start pushing the throttle slowly to 1.5, the idle then keeps that value. Only comes back down with the magic and fast kick on the pedal.

 

Cheers

Something is sticking. The fast jab means it overcomes the tight point and shuts the throttle disc which gives your low idle. It is as simple as that, you just need to find it and sort it.

[soeima 0]

Something is sticking. The fast jab means it overcomes the tight point and shuts the throttle disc which gives your low idle. It is as simple as that, you just need to find it and sort it.

Sprayed it all over with WD40 aswell. Will get a closer look into it.

Thanks Tom!

[Thijs_Rallye 87 4 Cars]

Only comes back down with the magic and fast kick on the pedal.

 

Have you checked if the TPS switches? Sounds to me the idle one might not switching correctly once you release the throttle slowly.

[DamirGTI 342]

Possibility SAD bimetalic disc not closing completely .. when the engine warms up and start to ide higher pinch the SAD hose and see if it affects the idle ... Of it does , if the idle drops , It's the SAD nog closing up .

 

The SAD needs both the 12v supply via heater element and cooling system heat to fully close the bimetalic disc within the SAD ..

 

D

[toolie72 67 1 Cars]

I'd also check afm is smooth in returning to closed

Just me probably!!!