Hello all,

I have a 99' Tahoe which I'm getting ready to install a 07' LS2 out of a TBSS. Can anyone tell me how to make my stock 99' tach work? I've been told I can do this by making a change in the ECM. Does anyone know how to do this?

Thank you for any all help!

Cheers...

 

OBS or NBS?

Please post if you get it going. It's on my list of things to finish on my '96 (OBS).

Just adding the pull-up resistor doesn't seem to have done it. Supposedly, changing the ECM setting for tach from 4 cylinder to 8 cylinder gets it done.

Good luck!

-KP

 

Thanks for the good wishes...

Yes, my 99' is an OBS...the last year they made them. That's what my understanding is...that somewhere in the ECM, in the settings, you can make the factory tach work...just need to ascertain that knowledge. Someone out there knows how to do this!

But yes...for sure it I figure this out I will post it.

Thanks again,
Russel

 

You can do it on an E38 ECU, but I don't believe you can make those changes on can E67 ECU like you would have from the '07 TBSS. You may need a converter from somewhere like Dakota Digital to do it.

 

Wow...totally not the answer I was looking for...dang! I do appreciate the idea of Dakota Digital. Hadn't thought about them.

I did find a plug-n-play kit from AutoMeter. I called them up, which they advised "We don't know if it will work or not..." They did say their tach adapter creates a 0-12 volt square wave, which may trigger my tachometer. However, without knowing for sure what my factory tach requires, they can't say for sure.

Does anyone know if this will work? Either way, I'll get with Dakota Digital and see if they have so kinda "black box" that will work.

Thanks again for the suggestion!

Cheers,
Russel

 

I did a lm7 in my dad 99 tahoe with I changed the tach output with hp tuners. I either doubled it or halved it. I cant remember for right now. The 0411 ecu was an easy swap wiring wise. Not sure about a gen 4 engine.