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Re: vacuum advance unit Posted by RS [Email] ![]() ![]() ![]() In Reply to: vacuum advance unit, eric, Thu, 28 Oct 2004 23:31:42 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I'd asociate stumbling more with a vacuum leak or a bad AMM than with a bad NTC sensor. Have you checked your spark plugs to see if the porcelains are black from running rich or white from running lean?
Have you changed your vacuum hoses and the rubber bushings that hold the vacuum nipples into the intake manifold and valve cover? Bad hoses are the bane of the 900T driver.
Also, assuming that it's a 16-valve 900T, make sure that the hose clamps on the rubber boots on the ducts from the AMM to the turbo are tight. They can be a major vacuum leak source. The bushing for PCV hose that goes into the plastic turbo duct can also be a good leak.
Now, if you get a kind of chugging and you're blowing black smoke when you accelerate, then it may well be that you have a leak in the ducting *after* the turbo. Check for loose hose clamps and splits in the rubber boots.
To see if the NTC sensor is the problem, you can check the resistance. Do a search on "NTC". There are a few posts with the resistance values at various temperatures.
For your distributor, it's always possible that vacuum pot is good, but the plate in the distributor that it turns in stuck. You should check the vacuum pot like aalto describes with the engine off.
What are you using for spark plug wires? If they're not Bougicords or Magnecores, that could be a source of low boost. Other non-shielded cables emit RF noise which the APC controller picks up on the knock sensor cable and interprets as knock and knocks the boost down.
You don't mention what year your car is (every little bit of info helps.)
posted by 65.217.4...
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