inthe10syet

I just got done doing a ported LT1 heads/cam swap on a 97 Formula, and turned out to not go well. Its a nice set of ported heads with around 275cfm on the intake side, and a pretty healthy cam, in the .560 lift range, on a 110lsa. Car wont run or idle anywhere above 450-500rpm. To start the car you must give it throttle, and then once started no matter how much throttle is given, the RPMs never rise. Let of the throttle and it dies. The computer has been reprogramed by PCM4Less, and has had all the emissions equpment dissabled, the knock sensor disabled, as well as custom tuning for the setup. The car does not throw or store a code at all during all of this. I put a scanner on it, and watched the TPS values and worked perfectly normal. The MAF gms for WOT were about 17.0. Im not sure if that sounds right as I havent paid attention to the values much latley. Map sensor is only reading 29.9in throughout the whole ordeal. The only strange reading I saw was the spark advance was set at -8.0 degrees, this isnt knock retard, this is the spark advance. It never moved from that reading. O2s werent hooked up as I had open longtube headers on at that point. Anyone have any ideas or leads? Im going to check the fuel pressure tomorow, as I had problems with the fuel pump picking up fuel at first, but I kinda doubt thats the problem.

Thanks for any help in advance.

IllusionalTA

Sounds like a map problem to me.. but not positive.. Check all your connection's.. make sure you ddin't miss any grounds and what not.. its going to be something so miniscule your going to kick yourself.. Good luck and keep us posted..

turbo_Z

a couple of things jumped out at me.

First you claimed the MAF was only reading 17 g/s at WOT?? Either you made a typo there or you have a real problem with the ol MAF sensor.

Second problem is the spark advance. Something is definitely up with that... you should see a figure around 35-39.

About the MAP sensor.. it looks fine to me as long as that reading is during WOT. If by meaning thru the whole ordeal you meant thru the entire log then you have yet another problem.

Maybe that PCM is bad?

inthe10syet

Well, the MAF readings are about on par with the RPM, keep in mind, this thing would never rise above 450rpm, at WOT part throttle or 1/4 throttle.

Here is what I have come up with so far.

The car in question is a 96, OBD2 car. My car is a 95, OBD1. Just for kicks, I took my OBD1 PCM, and put it in the OBD2 car. Amazingly, THEN it showed fault codes. With the OBD2 computer in the OBD2 car, even with every sensor unplugged, it would not throw an SES light on the dash, or show a trouble code on the scanner. Im not sure what was done to the PCM to do this.

This is what I got from the computer

Code 36 High Res Fault
Code 43, ESC fault (due to knock sensor being un-plugged)

Now, as stated above the car wont run anywhere above 450rpm, no matter how much throttle is applied. When I had the throttle at about 50%, and manualy re-set the fault codes with the scanner, the motor would rev up like normal, untill the SES light would come back on in about 3 seconds. From the code, it shows to be the opti going out, but only the High Res Fault showing, the car should still run correct? I cant see if the CPS is working properly, because the OBD2 computer wont show any fault codes, and the OBD1 computer doesnt have that feature. So does this sound like an bad opti to you? Id just like to get a second oppinion before I just go off and buy a new optispark.

Thanks once again.

96ZRDR

What scanner are you using?

Anyways, spark advance of 8 degrees at 400-450 rpm is not normal, stock tables show around 14 degrees. Are you sure that you are not reading spark retard, but you can assume the PCM will subtract max knock retard if the knock sensor is unplugged or it is from the incorrect year. Probably running in limp home mode.

Your say your map is 29.xx, if so (you are not reading BARO), this means you have not one inch of vaccum. (Huge Vaccum Leak).

In regards to the DTC's, just how old is your optipark distributor? Also make sure you have no wires or injectors crossed.