can't get my tach to work!!!! runnin the 04 gto motor, pin 25 of c206 is tach signal, well i hooked it up to my stewart warner tach, set to 4cyl mode. i don't get no movement at all from the guage. i set it to 8cyl mode, same crap...anyone got ideas? i tried some searches but came up empty handed.

 

Haha yup... Same here brand new Autometer pro comp and same b/s had me foiled for a while... Tried everything too. Called Autometer tech support and verified my wiring was okay and would have sent it back too if it wasn't such a pain to do so from Canada. After endless searches I found an answer.

Solution was to boost the signal from the PCM to the tach. It seems the output is not strong enough to power many aftermarket tachs so I put a 10K resistor to 12V+ ign and spilced that into the tach signal feed from the PCM to the tach and bingo shes alive.

I bought a pack of five resistors from Circuit city for five bucks.

 

i'll give it a shot,...hmm RIGHT NOW!!! lol...

 

Perfect!! thanks man.
oh by the way....Radio shack, 5 pack of 10k ohm resistors, $1.08

 

Dang I got ripped off.....

Glad it worked out for ya

 

hello, let me explain my situation. I bought a 89 firebird with a LS1 engine. the previous owner had installed an aftermarket tachometer 5 inch. I removed that big gauge, but my original cluster has a disorder. Watch the youtube video to understand my prob.

http://www.youtube.com/watch?v=CqwVG...ature=youtu.be
(sorry the video dosen't have sound)

..... The original cluster and the aftermarket gauge are both connected to the tach adapt model 9117 made ​​by Autometer, so the original cluster receives the signal from the tach adapter. Unless the rpm drop to 0 when I presses on the accelerator the rpm indicated is the same as the aftermarket tach. does anyone have a solution. Thank you.

 

Hope mine doesn't need it, but if it does... so i take a 12v wire and splice that into the tach signal wire coming from the PCM, but i put a 10k resistor in the 12v or the signal wire?

12v------resistor------"T" into signal wire?

 

Just so you know the firebird original tach wire will not work using the 10k resistor booster method.

I have my original tach and a autometer tach wired in and working off of the ls1 pcm.Original tach reads about 200rpm lower at all times.I just used a diode to prevent either tach from possibly back feeding eachother.

http://www.ls1tech.com/forums/conver...t-correct.html