230F idle speed

[AlexO]

Originally Posted by iain_o

As I say, you need to start at the beginning and diagnose the issue properly before any of us can tell you what to change. Or find a good garage that will take the time to find the trouble and fix it. Or a useful techy friend who will drink your beer and work on your car for you. It is almost impossible to diagnose remotely.

...or just leave it alone, as I recommended. As I said before, I'm really not sure that 750rpm number form the book is actually correct. In the 35,000 miles that I owned my 240 it never idled this low. In fact, when it did idle that low it sounded like it was going to die. It wasn't happy. The engine was always the most reliable part of my 240 and it always idled around 1000rpm.

I would get as low as 900rpm on a cold day and as high as 1100rpm on a hot day which I took to be an indication that, all things being equal, my engine was reacting to the air temperature. No biggie.

If you're keen on hunting down minute technical gremlins for the satisfaction of having you're car idle at an arbitrary rate then crack on but, otherwise, I would suggest taking a note from the old adage that "if it ain't broke, don't fix it".

Hope that helps,

Alex

[Clifford Pope]

I agree. Your idling speed seems close enough.

I too notice mine varies quite a lot for no obvious reason. Sometimes it seems happy at about 700 rpm, mostly in the 900 rpm region.
While warming up it has a habit of starting off quite high when just having pulled up or released the accelerator, but then on idling it gradually settles down.

The only thing I do feel isn't quite right is when very occasionally it momentarily stays up at 1200 - 1300 rpm, but can be induced to fall lower on blipping the throttle. I take that as an indication the IAV needs cleaning again, after which all returns to normal.
The engine does seem very sensitive to tiny build-up of dirt in the IAV, but I imagine that is a feature of a component that really only has one setting, and so gets a bit stuck at that point.

I do recall that when I had an LPG set up with a basic mixer, the IAV tended to have two sticking points, because the idling point was different on petrol and LPG.

[Nicholas Lewin]

Thanks for latest input all. My 3 bits of logic are:

First
Volvo manual says 750RPM. When the car does idle at that it is smooth and perfectly torquey, nice to drive (esp in traffic - this is SW London bear in mind) and quiet

Two
A flick of the ignition key at higher RPMs usually gets the car to revert to 750, but not always for very long. Throttle blip no effect whatsoever

Three
changing the IAV (now #5!) made a difference as did the MAF, but not consistently

So my feeling is that it is an electrical fault somewhere. I take your point about higher speeds when hot and also about old car and if it ain't broke...

I'll keep you posted, but again thanks. Nick