Car idle issue

[Big_Al 10]

Hey guys, I am looking for a little help with my new baby.

 

When I go my 16v Corrado off my mate, he told me that the idle valve doohicky was a little dodgy and would need replacing.

 

Sure enough it would idle very low, ocassionally stall completely when stopped at a junction as well as over revving on idle.

 

I have replaced the part and the car now drives much much better. Gear changes are smoother as the revs don't drop as violently, she doesn't stall now at junctions and so on.

 

However, she does still idle very low after being driven for a while or if I blip the throttle after first start in the morning. The rev needle no longer bounces around like an idiot, she just idles really low, then after a few minutes she will correct herself and be running fine.

 

As I am no mechanic, I have no idea what else to look for. Another friend has recommended blowing the engine through with some redex injector cleaner just incase there is something slightly blocked maybe.....

 

Any advice would be very welcome.

 

Cheers

 

Al.

[davidwort 0]

is it a 1.8 or 2.0L 16v?

[Big_Al 10]

tis a 2.0L matie

[davidwort 0]

you need to make sure the idle control is being switched on, should be a micro-switch under throttle body, sometimes with worn acc cables the cable doesn't release fully and so the switch doesn't get depressed. I think the 2L still has an air-bleed in the throttle body to set the idle, but don't fiddle with that until everything else is checked out, I'm assuming the basics like ignition and engine timing are set up right? 2.0L shouldn't have been fiddled about with on the fuel distributor unit, there is a tiny tamper cap on top of the unit where on the 1.8 there is a tube for setting the idle CO with a long thin allen key, this could have been messed with by someone before if the car has had idle problems caused by other things.

It's also possible the throttle position sensor is a bit worn in the idle position, the resistance it gives could be checked with a digital multimeter just to make sure it provides a smooth progressive reading around idle.

[Johnny H 0]

Is it the same for the VR6??

I'm having the same prob with my VR, In the morning you would need to keep the rev to about 1k or it will cut out but when warm it would be ok.

But now it wont tick over at all, think it has something to do with the idle control not opening fully,

Some help here would be great?

Thanks Johnny

[Big_Al 10]

Sorry for not replying sooner.

 

I have passed on the information you have given me here to my friend who knows more about this sort of thing than I do. We are looking at her today and hopefully will find something.

 

I have noticed that the car seems to work better once she has been used for a while and then switched off for say 10/20 mins. All the idle issues seem to disappear then......

 

If I get no joy today I think I will be calling C and R, get her in for a diagnostic and see where we go from there.

 

Will post if anything improves later today.

 

Cheers.

 

Al.

[Big_Al 10]

Ok, so after a long day of fiddling this is what we found out.....

 

The throttle body was rather dirty, this has been cleaned. The idle microswitch diddleflop was slightly loose so it was adjusted and secured. When a volt meter was used on the connections we found that when the throttle was in idle the meter still showed 12v going through it. Sometimes after a rev of the engine it showed something like .1 Looks like its not registering correctly what the throttle is doing. Not sure if this is the case obviously because I have the mechanical skills of a haddock. :)

 

We checked all the hoses and pipes for splitting and made sure all the clips holding everything together were tight and then sprayed all the joints with carb cleaner to see if anything was being sucked in, everything appears secure as no rev increase was seen.

 

The car now drives a little smoother thanks to the cleaning, but still idles very lumpy......

 

I have had to relent and book it in with C and R next week for a check over, hopefully they can see whats wrong.

 

Thanks for the advise though, was actually fun looking at bits of the engine I have never seen properly before and learning what they do and so on :)

 

Will update if and when I know more.

 

Oh, one thing we did notice was that there is a blue plug on the front of the engine, guessing a temp sensor of some description, that wasnt secured properly. But, plugged in or not, the car didnt seem to respond to it. Any ideas and could this be a part of the problem?

 

Cheers.

 

Al.

[Big_Al 10]

Rather late on from the original posting, but, finally got the car into C and R.

 

Turns out your thoughts were right dave.

 

After my mate had a look, he thought there was something wrong with the little microswitch in the throttle body. Steve at C and R today confirmed this to be the case. The idle controller wasnt even being switched on which was what was causing the issues.

 

One second hand replacement switch later and a quick tune up and the car is purring.

 

Thanks for the input, really helped :)

 

Cheers

 

Al.