924Board.org

[462avi]

Alright before any of you search police flag the message, I have used the search function. Here is the problem I am having. I am not getting a vacuum reading at idle with the engine fully warmed up. I attached my vacuum gauge to the small port just behind the throttle body. I don't get a reading until I slightly open the throttle then I get between 5 and 10 in/hg. I have disconnected and capped for (troubleshooting purposes) all vacuum lines and ports that attach to the intake manifold with the exception of the recirc valve line for the turbo. The motor appears to be running ok but I have been having problems getting it adjusted properly. I will warm it up. Then I set the mixture and idle settings and everything is working. I shut it off and the next day the idle will be at like 2500 rpm when cold and after warm up it is at like 1500 rpm. Its acting like there is a vacuum leak but it revs fine and I can not seem to find a problem. If the recirc valve in the turbo is stuck will the engine still run? Any tips would be appreciated.

Geoff
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2005 C230K
2002 grand cherokee with 4.7L

[Smoothie]

What year?

There is a vacuum port near the throttle that will behave the way you describe - no vacuum with throttle closed and some vacuum with it opened. That'd be not the right port to use for a normal vacuum test. It's internal opening is actually just upstream of the throttle butterfly when the throttle's closed - and it's there to operate the evaporative emissions...to open the eec valve to draw in fumes from the charcoal canister when the throttle's opened. See if you have a large vacuum line that branches off into smaller lines in the area between the intake manifold and brake booster. T into a line there (, but on the engine side of any check valves).
Here's where I have a dash-mounted combo boost-vacuum gauge Tee'd in -
http://pg.photos.yahoo.com/ph/smoothies931pics/detail?.dir=bdb3&.dnm=9e98.jpg&.src=ph
Those blue items toward the lower- and center-right are check valves.
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"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

[462avi]

Thanks Smoothie

Its a 1980. I guess I just figured that it was a good place to put the gauge. The Haynes manual is not real helpful in this regard. I will try your suggestion when I get home.

Geoff
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2005 C230K
2002 grand cherokee with 4.7L

[462avi]

Thanks again Smoothie you were right on.


Just listen to the dog!!!!!
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2005 C230K
2002 grand cherokee with 4.7L