View Single Post
Old 09-12-2002, 11:44 AM
Mervyn's Avatar
Mervyn Mervyn is offline
Registered User
Join Date: Jan 2001
Location: Singapore
Posts: 268
"As jp said, engine speed is a air flow problem not a fuel quantity issue."

Thanks JP and Steve, for drumming that into my head. Why didnt I think of that? I'd always thot the high idle is due to fuel delivery problems.

But what I couldnt figure out is how, when there is a vacuum leak, leads to the warm start problem? Steve, could you explain what is meant by "Large enough to impede lean restarts, high enough to raise the rpms. " Why I ask is because the warm start problem occurs only about 2 weeks ago, while I've been having the high idle for 2 years already ever since I bought over the car.

Took down some figures today:
Start from cold - Idle at 1300RPM (lasts for approx. 2mins before dropping to 600RPM)
With engine warm, "D" engaged to "P" - idle raises again to 1300RPM even after driving for about 30 mins. Drops to 600 again when "D" is engaged.
Warm starts - idle rises immediately to 1300RPM despite warm engine, and stays for about 30 secs before dropping to 600

Sometimes it gets rather embarassing to have a loud running engine in a stationary car, especially late at night in a quiet neighbourhood, or in an enclosed carpark.

JP: the throttle isnt open all the time, and besides, the high idle only comes on when the car is started or when engaged in "D"

Steve: I'll go check the decel dump valve tomorrow. WHat other vacuum items should I check? If it really is a vacuum leak, why is it affecting only the warm starts and idle, and not the central locking and/or other vacuum controlled functions? Is this going to be a trial-and-error method of slowly replacing vacuum lines and valves?

Pls advise, thanks again!

1979 W123 (200/M) Midnight Blue
1983 W126 (280SEL) Dupont Deep Black (Previously Pristine Silver)
Reply With Quote