Volvo 480 Club Europe

Hello,

My turbo idles fine from cold but when up to temp. it runs at around 1200. Cleaned the ICV with no affect. If you pull the plug off the ICV it makes no difference to the idle what so ever which is not good. No obvious air leaks.

What would be good would be to try another good ICV to see if to is that, but can anyone offer any advise on any possible causes I can look for please?

Mine new one does exactly the same when hot. The problem is that the switch that tells the car to use the idle control valve goes slightly out of adjustment when hot. It will just need moved a tiny bit-- it works fine when cold.‎

Mine is so slightly out of adjustment so just pushing the throttle body closed makes the switch meet and it idles perfectly‎.

To start: If I were you I'd check that you hear the micro switches go click when you slightly open the throttle and also when you release it back to rest. Do this with the engine off so you can hear it! 

When it is hot, with the engine running, just push the throttle hard closed. It shouldn't move but a little extra force could make the switch close and idle correctly. ‎This would prove if it is slightly out adjustment.
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Hope this makes sense-- it seems difficult to explain in words. If you need a better explanation, let me know. ‎

Hi James,

Thank you so much for that. I will try what you said, I think I get it. It does seem to click correctly but I will try what you have explained and see if it's just out of adjustment. If it is, like yours, whats the fix? New switch??

Thank you so much for your help.

ATB

You should just be able to move it ever so slightly if it is out of adjustment. It is on slotted holes. 

If it is more than being out of adjustment and breaking down when hot (think I've seen that reported on here)‎ then I believe it is a pretty common part to a few cars and you will get a replacement. 
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Funny, I only realised mine was doing it yesterday. I still don't have a re‎v counter so it is only the occasional noise that alerted me. ‎

Ok, thank you. I'll have a look later today and report back!

Any luck Rachel?

I've investigated mine further and the problem is actually that the throttle cable sheath is broken where it goes through the bulkhead which means it doesn't always come back to rest.  The microswitches are set correctly. ‎

A quick blip of the throttle and it does go back to the correct idle. ‎

This might not apply to your later car but do your intermittent wipers work? On my car there is a contact on the cable to detect full throttle and this puts the wipers to full speed when intermittent is selected and you are accelerating hard. This is what has broken and slightly restricts the throttle at rest. Fixed the wiper problem from advice on here by joining the wires together. 

Hi,

no still not fixed. I've not a huge deal as I don't really know how to fix it. Could be ICV could be TPS as the ICV makes no difference when you unplug it but could that be because the TPS isn't telling it work?? I don't know.

I didn't know about the wiper thing. My intermittent wipers do work though. I tap on the accelerator makes no difference either.

The easiest way would be try try a known working ICV and or TPS. Ade says he may be able to come over this week and we could do some swopping.

Thanks James.

Oh, I did what you suggested and nothing. Made no difference if I tried to force it closed, it was closed all the way.

My 1992 1.7 B18FP engine had a similar problem for ages and no amount of tinkering with switches, sensors, leads, ICV would fix it. As with your car mine would only idle high when the engine was up to temp. In the end I sorted it out by tightening the idle control screw (hidden under a green plastic cap on the throttle housing). I had to turn it a lot to get the result, but now i'm down to 900rpm again. I'm not sure what your engine is or if you've got the same idle screw (not all variants have it), but if you have, it's worth a try!