so the other day i was trying to load a new tune onto my 97 formula (obd1 conversion) and while the upload was in process my laptop crashed an kill my cars pcm. well i got ahold of another pcm out of a 94 caprice with an L99 in it and i was able to load my cars old tune onto the new pcm. well now with the new pcm for some reason my tach isnt working like neddle not moving at all!

any of you guys have any ideas as to what could be causing this?? i though maybe because the pcm still thinks its a 94 caprice, should i change the vin over?

 

no one has any knowledge of something like this?

 

so did i put this in the wrong section?

 

You are in the right section, but you have such a wild combination of parts. It will be hard to find anyone that has experience with a 97 obd conversion, 94 pcm (they had OBD??) L99. I'm amazed it runs. Good luck.

 

its not really wild, all it is is a heads cam lt1 in a 97 lt1 firebird. yes 94 had obd1, and the old pcm i had in the car was from a 95 z28 obd1 and i burnt it up so i got another pcm which is from a 94 automatic caprice that had the 4.7 L99 (smaller version of the LT1). i loaded my old tune from my 95 z28 pcm onto this new 94 caprice pcm and now my tach doesnt work.