2nd gear start?

[l67ss]

Found a switch in an early 90s gp 3.1 auto that said second gear start. Whats that about?

[Pontiac6KSTEAWD]

Mainly for winter driving, but it puts the tranny into second gear, instead of first, for trying to get out of snow/mud.

[rich_e777]

Always wondered about that myself:thumbsup:

[WhatTheFehl]

I think this was mentioned in a thread just recently.

 

Yes it puts the transmission into second gear, but it is important to note that while in that mode it just uses second gear as low gear. It will still shift through 3rd and 4th gear once you get going. And yes it is designed for use in slippery conditions, it makes it more difficult to spin out, and gives you more traction to get going. Think of it as a very early, rudimentary and cheap version of traction control.

[RobertISaar]

keep in mind, your PCM will have to support such a mode to use it correctly. AFAIK, no OBD2 cars did.

[will_s95]

I actually find this feature pretty handy. In the year that I've had my GP, I have never once been stuck, and that's saying a lot for Minnesota.

[WhatTheFehl]

I used it a few times when I had my 95.

[l67ss]

It was in a dirty but otherwise identical car to yours

I actually find this feature pretty handy. In the year that I've had my GP, I have never once been stuck, and that's saying a lot for Minnesota.

[Crazy K]

keep in mind, your PCM will have to support such a mode to use it correctly. AFAIK, no OBD2 cars did.

 

1996 GP??? they all had it. My 96 has it wired in, but running a 97 GP PCM(NA 3800, 4t60e) means it hasn't been tested. What's the worse that would happen if it doesn't work, Robert?

[RobertISaar]

PCM might set a trouble code? otherwise, no idea. if it happens to use the same pin as performance shift(which it almost always did for OBD1 applications), then it would cause that to come into effect.

 

internally, the PCMs didn't change that much until 98 other than the obvious 256 vs 512 BIN size, so the sampling circuit is likely identical for that circuit.

[l67ss]

That brings up another question, what about a performance shift button? U have a hole in my new console (traction control) that i wanna fill

PCM might set a trouble code? otherwise, no idea. if it happens to use the same pin as performance shift(which it almost always did for OBD1 applications), then it would cause that to come into effect.

 

internally, the PCMs didn't change that much until 98 other than the obvious 256 vs 512 BIN size, so the sampling circuit is likely identical for that circuit.

[RobertISaar]

if the calibration supports it, wire it up and it should work.

[gambler87]

Robert I have a quick question about the 2nd gear start thing. I put a 97 PCM and a 97 wiring harness into my 96 Gtp. Now I have a constant 2nd gear start light. Do u know what pin in the ecu and also what pin that might be on the trans that I would need to change to be able to get rid of that light

 

Sent from my XT1080 using Tapatalk

[RobertISaar]

from what i can see..... the 2nd gear start switch directly controls both the request line to the PCM and the bulb in the cluster. for some reason, the circuit is grounded constantly.

 

on a 96 GTP, looks like the signal wire goes through pin J1 on the C100 connector, then to the PCM's pin 33 on the clear connector(C2).

 

on a 97 Z34, pin J1 on the C100 is for fuel level signal(from the PCM to the cluster). 97 Z34 doesn't appear to use PCM C2-33 at all.

[gambler87]

So technically I could unpin the j1 on the car side of the c100 and then find the performance shift wire at the car side c100 and Repin that into the j1 pin and use my 2nd gear start switch for performance shift mode?

 

Sent from my XT1080 using Tapatalk

[RobertISaar]

possibly, assuming there is a performance shift function with your PCM and the engine-bay side of the C100 harness is already setup for it.

[ManicMechanic]

Ken and Saar: Could I add this to my van? *1995 Olds 4T60E

[RobertISaar]

5B(94-95 S1 3800, N/A and S/C) seems to have 3 transmission modes: normal, cruise and sport. effects shift points and TCC apply/release thresholds.

 

so, yes, it could be added in, but i couldn't tell you what the PCM will do with the U-van calibration. some "sport" modes were actually 2nd gear start, others were actually sport-looking.

[gambler87]

I have a 97 Monte Carlo ecu with a 97 Monte tune in it right now. And it has a cruise,sport,performance shifting tables. It also have good fuel and bad fuel tables both. The car side engine harness does have a performance shift wire

 

Sent from my XT1080 using Tapatalk