how much does the pcm actually control ur car and how it runs. i keep tellin my uncle it needs tuned but he cant believe it has that much control over the car. he just keeps repeating its a 94 not a 04.

 

Explain what you mean by "tune". If you're talking about the PCM, it only needs changed if you have changed engine components like intake, MAF, heads or cam and things like that. If you have not, the PCM does need re-programming.

If you are refering to "tune" as in tune-up, well every vehicle requires periodic maintenance of that type. Plugs, wires and dist. cap and rotor but it's better to change the whole distributor due to other things like optical sensors and the bearing. You know the items. Filters, perhaps O2's and clean the injectors.

As far as control by the PCM, well it's OBDI. It does not use as much input as OBDII, which came out in 1996. Even though the 95's used an OBDII connector. But it still monitors sensor inputs like O2's, MAF, MAP and TPS to maintain correct fuel mixture and even control idle speed. The PCM also provides a signal to the tachometer.

The improvement of the 94 over the 93 LT1 was the use of a MAF and sequential fuel injection. The 93 used speed density algorithyms and batch fired injectors.

You can see that it is more critical to replace items on a routine basis on PCM controlled vehicles then it was on the older non-PCM controlled vehicles.

I didn't mean to overwhelm you or intimidate you. I am certainly no expert but I hope that this is of some help. Good luck getting his car tuned up.

 

im not referring to a tune up, my car was dynotuned w/ a cc306 in it and now i have a smaller cam and was bored 30 over and the idle is at like 400 rpm's. my uncle thinks it is the iac, but i think it is cuz the tune was at a cc306 not at the current cam. he doesnt think the pcm has as much control and this is the 1st fuel injected car he has worked w/. he is an old school carburator engine guy.

 

The pcm pretty much does all the engine management. What you need is a way to monitor what the pcm is doing and seeing, like a scan tool or scanning software&cable and a pc.

 

we have one but it has only spit out low res thing which concerns the opti and that was only once. it shows that the rpm's are about 350-400 w/ it