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billjam billjam is offline
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Join Date: Aug 2007
Location: Perth, Western Australia
Posts: 1,985
Revs drop slowly when changing gear ... why?

When changing gear, my revs take forever to drop down to idle. (Forever = 2 to 3 seconds.) Not conducive to fast or smooth gear changes!
Idle speed is now also higher (at about 1100-1200).

I have been pointed at the vacuum control valve (the "gold" plated one in the center of pic). My other car doesn't have this problem so I swapped the valves over and it made no difference at all.
Yes - I have checked that the throttle is fully closing and isn't restricted or stiff in its operation.

This condition gradually developed over a period of a month or so a couple of months back. Even though it is now winter (in Western Australia), daytime temperatures are still 60-70F so I don't think that the cold(er) weather is a factor.

The car has also developed strange cold starting behaviour which might be related.
If I crank motor continuously, it takes forever (5 to 10 seconds) before it crawls into life. I have found that if I just give it a short burst on the starter (about 1 second), I can just catch it firing weakly and bring it up to idle with a little gas.
I have checked the fuel pressure accumulator and it holds pressure OK.
It always fires up immediately when warm and also on about one out of ten cold starts. Don't you just love intermittent faults!

Any hints for solving one or both problems will be rewarded with a smilie.
Old 07-13-2008, 09:30 PM
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