GMPP LS3 with GMPP Controller Tacho control

[ScarabEpic22]

For the new style GM electronics the engine and auto trans are controlled by completely separate modules, you just need to wire a TCM up and tie it into the appropriate circuits to have trans control. This is both an advantage and disadvantage depending on the car setup over the LS1 PCM that had both engine and trans control in 1 module.

Yes, you should change the VIN to be something like 1GN... so that EFILive can pull the appropriate PIDs for logging.

[TurboCamaro]

Thanks Eric

[ScarabEpic22]

Yep, Id talk to EFIConnection if you need custom harnesses made. I know a while ago they had a little bit of lead time, but they build them from scratch to your specs (length, auto/manual, LS1/E38/E67, etc) so that might be another option as well.

[68problemchild]

I know he is looking for a software fix down the road, but FYI.

This is giving me a working tach!!!

Now its off a bit, computer logger reading 750-800 and 1968 Camaro Tic Toc Tach reading 1000-1100 but heck it works. Current settings are

1201 = Crank
1202 = 6
1203 = 6

Taz, should I try "3's instead of 6's?

[Taz]

As before, not positive on E38's .... you're about 25% too high on the Tach ... try using 4 in each ... if that goes the wrong direction (ie. tach reading even higher) ... then try using 8 in each .... just guessing ... LS1-B man !!

It will take a little experimentation to get it right.

Did you need to use a "pull up" circuit, or did the ECM have enough power output to trigger the Tach ?

Regards,
Taz

[68problemchild]

No circuit. Straight to the TACH. Best result so far was "crank" and set others to "9"s.

Thx again.

[TurboCamaro]

It has been a while since this conversation has progressed. In reading back in seems the original question has been lost.

I am doing a GM Performance LS3 6.2L part number 192044097 with a GM Performance Controller in a 69 Camaro. The tach is operational however not displaying the correct RPM. I have read the Cal from the controller as an E67 (Cal attached above) and there is no control in the cal for the tach configuration. Has anyone had any success in configuring the tach in these controllers.

[Taz]

Thread got sidetracked ... apologies.

Do you have the instructions from GM for the ECM / wiring harness kit ? With no software parameters to edit Tach output, you're only left with hardware changes. I'm assuming the Tach is reading too high ? Similar to an analague Tach set to 4 cylinder, but connected to a V8.

Putting a resistor in line between the ECM output and the Tach should work if you are using the original '69 Camaro Tach. If your using an aftermarket analogue Tach, try setting it to 4 cylinder (rather than 8 cylinder).

Regards,
Taz

[ScarabEpic22]

TurboCamaro, do you have G120x tables in your tune? Im not at my tuning computer so I cant pull up your tune to check for myself.

Have you got the enhanced GM PIDs issue sorted as well?

[TurboCamaro]

No the tach tables do not exist in the tune. This is what I am trying to determine if there is a way to add them or reflash the computer with a stock LS3 cal or other?

I haven't addressed the advanced pids as of yet, first things first is the tach. Once the car gets closer to the dyno I will set the VIN and get the PIDs functioning.

No I don't have the GM instructions. We did one other car utilizing a tach adapter however you have to splice into the ignition wires and it in my mind is a rather poor solution. Typically in my experience as soon as you start splicing in it opens the door for problems down the road.