Quad-4 (1228707 ECM) Rough Idle Problem

[Will Remaklus]

> Would you happen to have a chip file?

Mike,

Yes, I have the EPROM contents for both the chip that is in the
car (a race calibration) and the GM production version.  Supposedly
the only major difference is the WOT and redline, but I have not
exhaustly compared the two.  I don't have them at work, so if you
can tell me which one(s) you would like to see, I will send it you
directly this evening.

> If this is a map system and you are still using the chip from
> the older app (maybe lower vac?) that might have something to
> do with it. Timing & fuel could change significantly as MAP
> signal fluctuates even a little.  What are the BLM numbers
> showing?

The BLM (if I am reading the correct word of the ALDL stream)
while idling has an average value of 120, standard deviation
of 4.5.  This data is from when the O2 sensor was only measuring
the output of cylinder #2, but it is probably representative.
As a comparison, while driving the average BLM is 128, standard
deviation 7.6.

The raw MAP sensor output is 70, +/-1 at idle.

Will Remaklus
Raleigh, NC

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