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Engine slowly running richer over a period of time...

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Old 05-04-2007, 12:04 PM
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Default Engine slowly running richer over a period of time...

About a month ago, I AutoVE tuned my MS4 cam'd LS1.
After that tune, it did not smell rich when idling and low speed driveability was great.

Been noticing lately a couple of things. Low speed driveability (i.e. bumper to bumper traffic) has gotten "harsh" and it smells very rich at idle.

Something tells me if I reset my fuel trims, I bet this "harsh"/rich condition will improve.

I am still running in SD mode since I have yet to finish tuning the upper portion of the rpm range on a dyno. WOuld bringing back the MAF help?

Thanks in advance for any suggestions!
Old 05-04-2007, 12:17 PM
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Could weather changes or other changing environmental conditions be responsible?
Old 05-04-2007, 03:39 PM
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Yeah, what was the weather a month ago for you compared to now?
Old 05-04-2007, 04:35 PM
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How many miles are on the O2's? I noticed my car running rich, got a code for non switching O2. I changed both fronts, seem to solve problem.
Old 05-05-2007, 02:38 AM
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Thanks for the input everyone!

I livein Hawaii, so the weather is pretty consistent from day to day, but I still plam on bring the MAF back on line to keep up with the changes in humidity level.

My o2's have less than 3k miles and AC delco oe parts.
The insufficent switch dtc is common with the LT headers, hence I deleted them from my tune.

I am sure my problem is going to have something to do with the overlap of my cam. Since it gets erratic readings at idle from the chop/overlap I think the pcm is trying to adjust tje LT's at idle which eventually become too rich...

Any other suggestions!




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