lsxRanger94

I didn't find this in the search of the site. Maybe it will help someone.

http://www.autometer.com/media/2650-1563.pdf

if it's already here.. Sorry for the repost.

Stormed_Norm

iTrader: (10)

So this is what would be required to make a tach work in a 1st gen Sonoma? The 9117 adapter, is what I am asking about.

lsxRanger94

If you are talking about a factory tach and you have the white tach wire in your LS engine harness, no. A 2003+ PCM (RED/BLUE)most of the time need a pullup resistor. 1/2 watt 1k ohm resistor wired in with 12v lead. What they are talking about with the adapter is if your LS PCM harness has no white tach wire.

If your harness has a tach wire or you pinned one in and are using a factory tach, then when you have the PCM flashed you can have it set to 6cyl tach signal. If your truck had a 4cyl no change to the pcm program needed. LS engines send a 4cyl signal NOT V8 unless changed in programming.

Aftermarket tachs have a 4,6,8 cyl switch to change the signal, which you would set to 4cyl. A resistor is need on some tachs to boost the tach signal.

My 05 L33 required the 1/2 1k ohm resistor to boost signal to my sunpro tach. If this doesn't help you let me know.

Stormed_Norm

iTrader: (10)

I have a 2004 pcm, with blue/green on it. I have a factory tach that was/is still for a 6 cylinder 4.3. I have all my gauges working except for the tach gauge. Lost on that wiring part of it, was thinking I would need the 9117 adapter. Or do I need to change something in the tune program?

lsxRanger94

If you can, I'd just change the tune to 6 cyl output from the PCM. If you have to pay to have it done, I'd still change the tune. If you use the adapter it changes signal to 8 cyl because it's wired directly to coils with no pcm signal. Then you would have to have the tach calibrated to 8 cyl, Too much hassle and extra wires. If you have an 8 cyl only aftermarket tach,then the adapter is a quick and dirty fix IMO.

http://www.hptuners.com/forum/showth...der-tachometer

Stormed_Norm

iTrader: (10)

Thanks for that link, old info is good info.