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Originally Posted by strych9
Very interesting. Thanks for going the distance and checking this out PQ.
All I can figure is that they either cleared the memory with test equipment during their testing, or as NFERNOSS said, a different fuse. Or, something altogether different fixed the issue.
The PIP does mention fuse #20. I suspect that this circuit may hold some parasitic voltage for a short period of time, so that's why GM calls to remove this fuse for the ECM reset. That's why I specifically stated to wait 45 minutes before testing, so any parasitic voltage could bleed off before testing. Good stuff.
I would have thought that GM would have revised the ECM logic to start at maximum timing advance with every new start of the engine, then back off and hold back advance as dictated by the knock sensors until the engine is restarted again. This is the logic that most cars use.
GM engineers, please speak up.
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Agreed.
One thing I know is that the car WILL get stuck in a low octane retarded timing state. My complaint all along was that it didn't revise automatically and I suspect that it's a way for them to keep the car at it's uber safest level to not have as many warranty claims. I know there are people out there who are stuck in the low octane table and don't know it.
I'm a little confused at all of the people who SWEAR that it helped. Mine was at the dealer just before the fuse pull. (It was always at the dealer for this. The dealer appologized to me for telling me that I was wrong when that bulletin came out about the issue) I didn't do any timed testing between the last time the car was at the dealer and the day I did the first ever 'Fuse Pull'. The dealer told me they reset the computer but I was already in 'Done' mode with the car waiting for the engineers to put out a TSB.
To tell you the truth I was hoping I'd find some juice in at least one of those fuses. It was my fuse pull that blew this whole thing open and I will own up to that. My findings on my cars immediate and undeniable performance jump had to have been from my last trip to the dealer. And we were right about the low octane settings not adjusting back to a more advanced timing (can't deny that, it was the engineers that said that) but the fuse pull for the moment seems to be egg in my face.
I tried to get EVERYONE to time their cars before and after but NOBODY did. If you go through the fuse pull sticky you'll see me saying it over and over and over. I finally just gave up.
And now We'll all be laughed at pretty hard. I will take that square on the chin and accept that. But I think anyone that had the same chain of events in my shoes would have done the same.
I feel a little responsible for this. So I'm going to make an effort to find out exactly what fuses and where they are so that we can let people know properly. After all, there are people out there with SSs that are nannied and don't know it.