Anyone dyno'ed their LT1/4?

[Hrtbeat1]

I had my LT4 dynoed back in April. I am going to get it re-dynoed next week now that I've done some mods. I talked to the dyno shop and asked them why the first dyno was graphed as HP and TQ vs speed and not RPM. I was told they could not find a tach signal. I have searched the FSM and can't find anywhere the tach signal comes from. The only thing I have found is the tach signal comes from the ICM (igntion control module) and feeds to the PCM. I guess I could jumper off this wire feeding the PCM. I think its pin 13 of the black connector (I'm going off memory and not looking at the FSM.)

Where did you get your tach signal from?


G

 

[fredk]

It's the white wire in the grey connector that plugs into the coil.

Fred