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Shift point v. fuel cutoff problems

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Old 06-04-2007, 10:40 PM
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good info in this thread.. keep it going guys..
Old 06-04-2007, 10:56 PM
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I think Holty has hit the nail on my issue. With the fuel cut off originally only 400 above the shift rpm I think it was just barley hitting it. I bumped the fuel cutoff to 6600rpm and dropped the 1-2 WOT shift speed by 4mph and the 2-3 WOT shift speed by 12mph. When I get a chance to test it, I will post up. Not too many places around here to get a Tahoe on 24's going 100mph without getting some police attention.

Plus, anything over 80 mph and she really stops pulling
0-80 is fun as **** though
Old 06-05-2007, 06:29 AM
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Keep in mind, again, dc_justin mentions that your part throttle shift table has a mph setting in the 100% TPS spot. If it's true that your pcm looks at this column as well then you have three qualifications to shift. WOT shift RPM, WOT shift MPH, and PT shift MPH. Do a double take on this table, make sure that MPH isn't that high either. Not so sure I believe him...hehehe, but it is certainly worth a look. (jfwy justin)

I command 6200 on my 2/3 and it shifts at 6000 to 6100 usually. Sometimes, sometimes it'll go to 6300.
Old 06-05-2007, 07:10 AM
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Originally Posted by Holty
My issue did turn out to be not a ground issue, but just the simple issue my my wot mph was too high so i was hitting my fuel rev limiter before it shifted. i just had to reduce my wot shift mph a few mph and it fixed it. i've also found that the truck does take 300-500 rpm to actually shift after the shift is commanded. for example, if you zero out your wot mph and set you 1-2 shift to 6100, it still might not shift until 6500 or so.

zippy, the issue you're thinking of is something completely different where i would just be driving down the road and randomly my truck would shut down and start back up within 1 second. that problem has either gone away on its own or has been in hiding for awhile now. lol

I was thinking that you were having both problems, unfortunatly my memory isn't good enough to remember the details... That was alot of drugs ago...

Either way, that shift point issue has been a problem for many before. Hope you get it dialed in.
Old 06-05-2007, 05:54 PM
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Originally Posted by dewmanshu
Keep in mind, again, dc_justin mentions that your part throttle shift table has a mph setting in the 100% TPS spot. If it's true that your pcm looks at this column as well then you have three qualifications to shift. WOT shift RPM, WOT shift MPH, and PT shift MPH. Do a double take on this table, make sure that MPH isn't that high either. Not so sure I believe him...hehehe, but it is certainly worth a look. (jfwy justin)

I command 6200 on my 2/3 and it shifts at 6000 to 6100 usually. Sometimes, sometimes it'll go to 6300.
Went through and looked the 100% spot on the 1-2 shift was 36mph where as the WOT table says 32mph. The 2-3 shift was set at 67mph where the wot was at 55. Very interesting.
Old 06-14-2007, 06:09 PM
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Took the truck to Biloxi Tuesday and Mobile today. I got a few chances to run her hard. I still ran into the same issue with the battery light on the dash coming up once I get in the high rpm just prior to a shift. Got a code thrown today as well so I pulled the history and got thses:

P0430 Catalyst sytem low efficiency bank 2
P1637 Generator 2 L-terminal circuit

The P0430 codes were both set at idle so I don't think they are an issue as I have high flow cats
The P1637 was set at 78mph @ 2291 rpm with a throttle position of 14% so I don't see how that could effect the high rpm shift. How do I fix this code? What would set it? I have a 200A alt so charging shouldn't be an issue.

What do you guys think?
Old 06-14-2007, 08:06 PM
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how did you run in Mobile? I am not good with trouble codes so i will leave that to some of the gurus around here lol..
Old 06-14-2007, 08:31 PM
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It wasn't at the tracks. I was going to gamble and then drop a buddy off at the airport. I was playing around on the interstate.
Old 06-14-2007, 08:40 PM
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ahh lol... wish i would have seen you around.. I would have given you a run or two hehe
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