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Old 10-28-2006, 08:51 AM   #1
Scooby Newbie
Member#: 103373
Join Date: Dec 2005
Default Low RPM Low Load Issue

Guys I've got a strange problem that start a couple of days ago. So it could be mechanical.

Taken -12% from the MAF table due to running a Fuel Pressure Reg to get as close to the AFR Maps as possible. Also the car has run minus MAF setup for 2 months with no known issues.

The car has developed a stutter/surging condition at below 2000rpm and idle is rough. Looking at the logs the diagnoses looks as...

1. Idle is rough and evident from log 1 AF Correction adding fuel, then suddenly settles down to normal - see log 1.
2. Cruising below 2000rpm the car will stutter/surge sometimes violently. Again AF Correction is adding then substracting fuel frequently - see log 2

*** How do you post at NASIOC? Logs are too long to wrap around code! ***

What mechanical problems should I be looking at? Spark Plugs etc?

Now above 2000rpm the car hauls and runs normal with no CEL's etc.

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Old 11-01-2006, 01:52 PM   #2
Scooby Guru
Member#: 48219
Join Date: Nov 2003
Chapter/Region: MAIC
Location: Pittsburgh, PA
. Always drive
the race line .


you're tuning in a weird way. Increase the injector scalar instead of removing 12% from the MAF table. The car thinks you're in a lower load zone then you really are causing you to run higher timing than you should. That's the first of your problems.

I know that wasn't much help to your current problem but check for intake leaks.
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