95 Jimmy 4l60e shift points

[Dann757y]

My knowledge of the 4l60e is limited, so I hope someone can steer me in the right direction. I have a 95 Jimmy 4WD I'm restoring, 120k, my new 4.3 is installed and running. The last owner had a trans put in, junkyard trans supposedly rebuilt. The trans 1-2 shift points are too high unless I take my foot off the gas pedal! In other words, it seems to wind out to 2800 rpm in 1st and 2nd, unless I take my foot off the gas. Then it shifts at a lower rpm. So, it seems to wind out much too long before 1-2 shift, unless I either stamp on the pedal or take my foot off the pedal. I know the TPS is supposed to determine shift points, I checked the voltage change and it seems OK.
I don't have a local trans shop I trust. (surprise)
My ideal would be a sooner more consistant 1-2 shift point.
Thanks if anybody can help!
Dan

[EC_Tune]

What is your fuel injection setup?
Is the PCM under the hood? If it is, Tunercat software.

[Russ K]

I have Tuner Cat for the 1996 to 2000 Vortec Trucks. But the 1995 with the pcm on top of the coolant tank is a year by itself. I tried to read a 1995 4.3
S10 with the under hood pcm and the software wouldn't work. Tuner Cat is not supporting that model.

Russ Kemp

[Bill@HPTuners]

its obd1 flash...i think they support it...just not with the obd2 stuff

[Dann757y]

Thanks for the replies! The computer is on top of the coolant tank. The fuel injection is with the "spider" inside the intake. It's a Vortec motor. I put a long block in this vehicle and have a couple thousand miles on it. I brought this truck back from the dead. I am computer literate, I build my own PC's, but this is another iron in the fire that I need more info on. I have spare PC's that I could get set up at the small shop I rent. I checked out the Tunercat site. Do they sell just the software? Is there an interface cable that comes with it? Do GM dealers charge exorbitant $$ to tune? I'm in NJ- if anybody is close and can help me, I'll travel and pay to get this straightened out.

[LittleNoMUC]

Tunercat doesn't support the one-year OBD-I Flash S10's - even the OBD-I Tunercat does not

[gman4dx266]

Thats strange that if no one supports the computer in your truck, then how would the settings get changed? If everything else checks out, and its nothing to do with the trans, then id probably start lookin for a replacement ecm to go in the truck on ebay or something.

[EC_Tune]

Heh, you want to see real wierd, there's a 4.3 that has a memcal (chip style) AND flash memory... Go figure that one out.. LOL

[gman4dx266]

Heh, you want to see real wierd, there's a 4.3 that has a memcal (chip style) AND flash memory... Go figure that one out.. LOL

Man thats just gay. How would one go about changing such a thing. I mean, in his case, someone obviously did. Perhaps someone physically desoldered the chip, and did it that way...but thats quite a big production..Id certainly do more than just shifts while i had the chip out.

So why would it need both types of chips (memcal/flash)?

[EC_Tune]

Only GM knows... They on occasion do some VERY wierd things.