On my '95 Camaro Z28, stock Lt1 my emissions inspector is having a hard time trying to get rpm pickup with either #1 spark plug wire (cannot get to) or using a proximity sensor. He moved all over the engine with that and the rpm's are very sporadic. Does anyone know the best way to attain a good rpm read on these engines. Thanks much, Bob

 

He can use the diagnostics connector. Find a different inspector, this one shouldn't be allowed to do emission inspections.

 

number 1 plug wire is the easiest to get to,,, what is being used to try and get a reading?

 

Z28pete; are you referring to the OBD1 connector? He does use that and his diagnostics machine is a brand new 20K unit. No need to be sarcastic, he is well qualified. And craby; he is using a proximity sensor, much like a spark plug connector but all you need to do is get close to a wire. It senses the discharge to a plug by induction. Thanks for the replies guys.

 

What the emissions guy is trying to do would work for hooking up a timing light, not a tach. You need an ignition pulse for the tach, not spark at the plug wires. But Pete was right, the guy doesn't know what the hell he's doing. The best place to hook up the tach would be on pin A13 at the PCM: http://shbox.com/1/1995_pcm_conn_a.jpg

 

i have a voltage tester like that and had no problem getting it on number 1 wire before i changed to a coil per cylinder setup.