Wavery Idle - Volvo 480 - dan
Hoping to confirm my suspicions:(In no way related to my intent to swap out the top half of my engine BTW).

I drive a volvo 480 with a rock solid idle at 850. After a recent service, (although like all things maybe it was there prior, l just didn\'t notice?) it appears the idle now slightly tremors between 850 and 900. You can feel that the engine is not idling smoothly through the stick/floor/steering etc.. It comes and goes and l haven\'t been able to pin it down yet.

My suspicion is that the sparks have been replaced with ones that don\'t \'agree\' with the engine yes/no?

regards,
dan
Wavery Idle - M.M
Dan,

Still wavering?

Oddly enough I sometimes stress over this slight idle fluctuation after a service, even when I know I haven't done anything to cause it.

Now I make a point of checking this when a car arrives. Some seem to suffer this slight variation when hot/cold/all the time. If owners are unconcerned, and the car runs well otherwise, I try not to spends folk's money looking for an elusive 50rpm waver.

The worse vehicles I ever looked at for this are old BX 1.9GTi's and the Pug 205 with the same engine. Some are complete pigs and will hunt as you crawl in traffic. This was commented on in road tests when these types were new so what chance is there when they are 15 years old!

David W
Wavery Idle - dan
Cheers for the answer David,
It wouldn't normally bother me, except you can feel the lumpy feeling through your feet. I will be stating which plugs to use next time and will forget it in the meantime (as you suggest) given the car runs great other than this.

regards,
dan
Wavery Idle - dan
Argh!
I'm gettng chasing now! When l depress the clutch when coming to a stop the engine starts to chase, once up to about 1500 from 850 then immediately up to about 1200 a couple of times, before settling. It reminds me a little of the engine rev you get when you first start an engine.
What's going on?
David?
regards,
dan
Wavery Idle - Cyd
check for air leaks upstream of the throttle plate. Perished hose, leaky gasket etc etc.
Also check the plugs for signs of damage to the ceramic. Similarly, check in the dark for any runaway sparks from the HT leads.
Wavery Idle - Richard Hall
Is 'chasing' the politically correct, fox-friendly term for what used to be known (and is still described in most workshop manuals) as 'hunting'? Good thing there aren't any Hillman Hunters around any more - it could get very confusing.

Richard Hall
bangernomics.tripod.com
Wavery Idle - dan
More likely a mistake on my part. :grin:
Wavery Idle - Volvo 480 - B18BFT

Hello Dan, i know what do you mean with wavery. You can feel teu car slightly shaking. And runs "almost like" in 3 cylinders only. Reaching the 2000 revs,

trepidation disapears.

I have a 2988 480bft as well and i'm going through the same issue...

I've cheked maf resistence and its ok, ground points, leads...

Have you managed to discover what was the fault?

Regards

EM

Edited by B18BFT on 03/02/2018 at 04:03

Wavery Idle - Volvo 480 - SLO76
Not sure he’ll still have it or be monitoring this thread nearly 16yrs later (last post was in June 2002) but I always did have a soft spot for the Volvo 480 despite its flaws.