Running Rich
Thread Starter
|
Member
Joined: Mar 2002
Posts: 27
Likes: 0
From: Hampton,Va
Running Rich
About a month I replaced my coil pacs and put in new plugs, Truck ran great, then after a couple of weeks it would sutter on WOT shifting from 1st to 2nd. I have an ATI Procharger and a Superchip Flip-Chip on a 4.6L. I did adjust the FMU a 1/4 turn and tried it again with the same results. This went on for several attemps and never improved the results. A couple of days ago I decided to pull the chip and reset the computer, did this and presto the truck does not bog on those shifts. Went like this for a day or so then decided to reinstall the chip. Dissconnected battery, reinstalled chip and the problem is gone. I guess what I am asking is if the parameters on the chip change as time goes by and mileage gets on it. The chip was in for about 3 months or about 2000 miles. Is the chip compensating and giving to much fuel at this point. 
Last edited by MHZMAN; Nov 8, 2002 at 03:46 PM.
Former Sponsor
Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Hi MHZMAN,
No, the Superchip's program does not change over time. Adaptive strategy is of course at work, and will make some changes as the PCM adapts to it's new programming as it accumulates the first 350-500 miles, but that's all over within about 350-500 miles in those model years, not until the 2001 model year do we see that having any real potential for noticeable extended effect after that many miles, and even then it's relatively rare, and doesn't cause your reported symptoms.
I would not try changing the FMU's setting without doing A/F ratio testing, as without that testing you're only guessing, and that could indeed cause a problem, especially if you are leaning it out. The Superchip is tuned based on the FMU being set as recommended in the supercharger manufacturer's documentation in the older programs, and in the newer programs it will be based on the results of the A/F ratio testing that has been required since Feb. 1st of this year, and anytime you change that you're altering your A/F ratios across the board as that is a gross adjustment, and there's no telling what has happened to A/F's as a result without proper A/F ratio testing after any change in the FMU setting.
To give you a direct answer, the FMU's provide higher rail pressure, and the natural adjustment from the PCM over time, if it were being driven often enough in a manner to have high rail pressures much of the time would be to shorten the pulse width and effectively lean out the A/F, not fatten it up.
ATI's are "blow thru" systems, and that can cause wierd symptoms, including what you are reporting, as well as idle quality issues, etc. That being said, the ATI owners we've provided the tuning for generally run well, and aren't plagued by problems like this.
You'll need to give us a call to go over this properly.
No, the Superchip's program does not change over time. Adaptive strategy is of course at work, and will make some changes as the PCM adapts to it's new programming as it accumulates the first 350-500 miles, but that's all over within about 350-500 miles in those model years, not until the 2001 model year do we see that having any real potential for noticeable extended effect after that many miles, and even then it's relatively rare, and doesn't cause your reported symptoms.
I would not try changing the FMU's setting without doing A/F ratio testing, as without that testing you're only guessing, and that could indeed cause a problem, especially if you are leaning it out. The Superchip is tuned based on the FMU being set as recommended in the supercharger manufacturer's documentation in the older programs, and in the newer programs it will be based on the results of the A/F ratio testing that has been required since Feb. 1st of this year, and anytime you change that you're altering your A/F ratios across the board as that is a gross adjustment, and there's no telling what has happened to A/F's as a result without proper A/F ratio testing after any change in the FMU setting.
To give you a direct answer, the FMU's provide higher rail pressure, and the natural adjustment from the PCM over time, if it were being driven often enough in a manner to have high rail pressures much of the time would be to shorten the pulse width and effectively lean out the A/F, not fatten it up.
ATI's are "blow thru" systems, and that can cause wierd symptoms, including what you are reporting, as well as idle quality issues, etc. That being said, the ATI owners we've provided the tuning for generally run well, and aren't plagued by problems like this.
You'll need to give us a call to go over this properly.