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Old 01-07-2008, 11:49 AM
Registered User
Join Date: Jun 1999
Location: Austin,TX
Posts: 17
Fuel trim and fuel pressure questions/problems

Hi guys I just went through the MAF errors P0170 and P0173 and replaced my MAF. The old MAF had my long term fuel trims at about 7 to 8% and the new MAF is giving me reading of -18%. I checked my fuel pressure and it is at about 58 psi or 4 bar. Is my fuel pressure too high or what else could be causing the computer to think the car is running rich?

I have gone through the all of the ventilation hoses and connections and eliminated all of the vacuum leaks. If I cause a vacuum leak the false air causes the long term trims to go positive. The trims are within less then 1% left to right.

I read about a dynamic test where you read the air flow on the MAF at full load and 4000 RPM but I have not found the test value in the WIS or the expected fuel pressures. Can someone post this info?

Once again my problem is the car wants to be RICH and the adaptives are LEANING it out the reverse of most of the MAF issues.

The car is a 02 E55 with 97K on it.


06 R350 with sport package
02 E55 Black on Black with most options
91 Range Rover GDE
8X 280TE
53 356 Cab
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