Volvo 760 Behaving Badly

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Tue 17 Jun 2003 22:53
Volvo 760 Behaving Badly - Greenparrot
Hello people
I post this description of faults in the hope somebody out there has had the same problems.
The car is a 1987 Volvo 760 2.3 Turbo automatic, the problems are as follows;
When the car is started it idles correctly, select drive and then select park or neutral and the engine revs repeatedly from idle to approx. 1600 RPM over a two second cycle. This problem
can be overcome if the revs are held at 2000 RPM for a short period and then released.
The second problem is an almost cutting out of the engine at around 2-2500 RPM in any gear, revs freely when not under load.
The car is the in-laws who live a 3 hour drive away and unfortunately this was as usual sprung on me on a visit last weekend under the excuse "We don't like troubling you" - suppose I should be gtrateful really, but some warning would be nice.
The jobs done over the weekend include; Replace distributor cap,
rotor,leads,plugs,idle control valve,clean throttle body.
Good increase in performance but no help in curing fault(s).
Personally I think it is the MAF unit but do not want to go to the expense as the car is up for renewal next year.
As always any help is much appreciated.
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Tue 17 Jun 2003 23:00
Volvo 760 Behaving Badly - Aprilia
I had this on my very troublesome BMW 7-series; it was the idle air valve in that case.

If you've replaced that component, then I'd tend to agree its the MAF. If its hot wire/film you could try cleaning it with alcohol. If its flap-type then lift the cover and clean the tracks with alcohol and a rubber.
You could monitor output with a DMM as you slowly increase rpm and look for any 'noise' or 'drop out'.
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Tue 17 Jun 2003 23:18
Volvo 760 Behaving Badly - Greenparrot
Thanks Aprilia, good advice - as I said I went there without prior knowledge so didn't think to pack my meter along with my socks, I'm going down there again in two weeks time 'fully loaded' to try and get to the problem.
I did mean to mention that I did clean the MAF as well as checking all connections, breathers etc.
I think like you it's time to fear the worst!
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Wed 18 Jun 2003 06:24
Volvo 760 Behaving Badly - Andrew Moorey (Tune-Up)
Throttle position switch may be at fault here.
Andrew


Simplicate and add lightness!
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Wed 18 Jun 2003 20:08
Volvo 760 Behaving Badly - Greenparrot
Thanks for this Andrew
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