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Re: Klaus still cutting out on acceleration. (archive)
[ Follow Ups ] [ 7-series (E23) Message Board ] [ Msg. Board FAQ ]
Posted by ATLD on September 17, 2001 at 16:41:36:

In Reply to: Klaus still cutting out on acceleration. posted by Scottie 85_535i 84_745i San Jose CA on September 16, 2001 at 14:47:55:

Does anyone have any suggestions that I should try next to eliminate the cutting out problems I am experiencing. (For those of you that don't know, my 745i cuts out -- like it is running out of fuel -- under high acceleration demand -- low or high RPM -- at any speed.)

Scottie,
It very well might be the turbocharger. Do you have a boost gauge? As you might know, the Motronic unit monitors the boost pressure after the turbine in the intake manifold, if it reaches (here it may vary) about 10psi, the engine shuts off momentarily (suppressed ignition), same as if it senses a knock. this happened on mine when I accidently miswired the vacuum hoses that go to the wastegete's controller (the little cylinder on the ari mass flow meter with three vacuum hoses and an electrical connection). Luckily I have a boost gage, and no one was as surprised as I was when I cought it rising to 10psi, then the engine cut out so it really wasn't that much fun (that really is what a "chip" does, stops the engine from cutting out). Note: with the wastegate functioning improperly, you can get ~10psi with 25% throttle, so don't thing this only happens when you floor it. It happened to me in a parking lot.

If you think this may be your problem it could be one of four things:
-The wastegate is stuck closed (pull it off and check it. really easy, 4 bolts).
-The wastegate controller "solenoid" (the one refered to above) is broken and stuck in the turbo position. (pullit off also, apply power, see if air path changes.)
-The wires or vacuum hoses are incorectly run or damaged. Obvious.
-That I don't know what I'm talking about and were all screwed.

Let me know of this helps.
Adam T. L. Delecki

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