brianbajnauth

Hey since I finished my swap in to my 87 gta trans am my tach worked for a couple day and then just stopped. I had two 10k resistors on the tach signal output wire form the pcm to my stock tach wire in the car. The tach just stopped working just like that. I tried hooking up two different after market tach nothing works. I hooked up my obd2 scanner and it shows the rpms. So Ecu is getting signal out not putting out any signal. Any ideas?

brianbajnauth

Anyone?

Aston Tibs

iTrader: (3)

I only used one 10K resistor in the line. Check your connections and make sure something didn't come loose.

brianbajnauth

Thanks for the reply

I checked and rechecked the connections. Is it possible that the pcm is not giving a tach output for some reason

JoeNova

I've never used a resistor with an aftermarket Tach and an LS and never had a single issue.

imma_stocker

iTrader: (19)

Things rarely just stop working for no reason.

Trace the wire from tach to PCM, every foot or so check the wire for voltage. Also verify the pull-up voltage source is still live. I don't know why you need 2 resistors, that might be causing other issues.