running extremely rich
10-13-2009, 03:55 AM
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running extremely rich
I have an 88 s4 with a manual transmission. It has started to run extremely rich and the idle is erratic. I have tested the temp II sensor the TPS switches and replaced the o2 sensor. The exhaust smells rich and mileage is abysmal. When I rev the engine it runs acceptably but not as crisply as it should. I asked on the email list and Wally suggested the fuel regulators and dampers. I checked and there is not any noticeable wet fuel. What else is there? How do I test for a bad LH unit?
10-13-2009, 05:48 AM
#2
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There is a MAF failure mode that makes the car run very rich. If you send your MAF to my agent Louie Ott in OR he will test it for you on his calibrated flow jig, for a nominal charge.
A faulty LH can cause rich running, but I would test MAF first.
A faulty LH can cause rich running, but I would test MAF first.
10-14-2009, 01:33 PM
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My 88 S4 had a bad LH unit, replaced that and everything was fine...that was solved in very fast timeline by 928 Ecu repair in the Netherlands by very helpful Theo & Paul.
Few months after that the MAF's hot wire broke off...JDS-Porsche made excellent job of repairing that! The car has NEVER been running so smooth as it runs now, also the fuel economy got a lot better than before.
The easy way to check which component is broken is to swap a known good LH or MAF into your car and see if there's any effect...
Few months after that the MAF's hot wire broke off...JDS-Porsche made excellent job of repairing that! The car has NEVER been running so smooth as it runs now, also the fuel economy got a lot better than before.
The easy way to check which component is broken is to swap a known good LH or MAF into your car and see if there's any effect...
10-14-2009, 08:40 PM
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Is there anyone in the Los Angelus area that would be willing to let me test my LH and MAF units in their car or theirs in my car? I live in Woodland Hills part of the San Fernando Valley.
10-14-2009, 08:40 PM
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Is there anyone in the Los Angelus area that would be willing to let me test my LH and MAF units in their car or theirs in my car? I live in Woodland Hills part of the San Fernando Valley.
