I have a friend that just got his heads and cam car back from the shop. He switched to obd1 out of automatic car and when we first intially started it it locked out 2nd and 3rd(cags) but then put on the cags eliminator and it unlocked the gears. we figure it did this because the computer came out of a automatic right? Also the car has no acceleration right now and when you try to get on it a little it pops bad. We put on 30psi injectors because we knew it would need it. we havent ran data master on it yet to see what its doing but we think its running lean. The cam is identical to a 306 cam with a little bit more lift and has stage three heads from a local head porter. Any ideas on why its poping and has no accleration right now?. If you need more info i'll be more than happy to provide.

 

If the PCM came from an automatic, it would be setting codes without the A4 being there, but can be flashed with an M6 file and it must have been if CAGs was working. That can be programmed out or you can use the resistor trick, sounds like your using one of them.

A 306 on stock tuning is going to need a good amount of timing work, especially for driveability, and of course AF adjustments. Without logging and some tuning, this is how the car is going to continue to run, so there is no real use in guessing whats wrong until you can log and look at it for yourself, because right now we know everything is wrong, timing and fuel. Bumping the idle up to 900-1000 RPM would also help out.

If you dont yet have some of the several 306 example files on the net, I can try to post a couple links to some, or post the one I used as my baseline, I made almost zero timing changes.

 

Thanks for the reply:


We have the idle bumped up to 800-850 and it idles good. We are going to have it scanned to see what all its doing but even though the car needs to be tuned shouldnt it have more acceleration than stock? becasue right now its very sluggish.

 

800 is the stock idle for an M6 car, I've gone that low too but I liked 900-950 better myself.

I tried a mail order tune for a baseline and it ran worse than stock with those timing tables, so I dont doubt at all that bone stock timing with a big cam is going to be slower than stock, dont doubt it at all. Plus split BLMs are very likely, and thats going to hurt power everywhere in a pretty big way.

 

Mean LT1, you need some serious tuning! Definitly timing adjustments, but even more then that, fuel adjustments because I am willing to lay down money that your running way lean right now. I put a set of heads on my 95Z and it ran terrible until I got my A/F mixture setup. It was trying to run above 15:1 before tweeking on it. The dyno chart on that run wasn't even smooth. It was pretty jagged. I'm assuming this was the computer trying to compansate, but once I got my A/F dialed down to about 12.5:1, everything smoothes out and it pulled hard. Just the A/F ratio adjustment gained 15 horses and fp torque at the rear wheels and smoothed things out dramatically. And this was just from a head swap. I already had a program in there cause I had a cam. You need programming for both heads and cam, so I would imagine you would have even more dramatic effects. I wouldn't be too worried. You'll get the performance out of it, but you just need to reprogram. Good luck.

Ken R 95Z

 

Even with "old tech", you dont put a cam on a car hoping to make another 75+ HP and keep the stock jets in the carbs, it just doesn't work quite that easily

 

Thanks guys, i'll keep you posted.

 

Well just after we just got tuning the car up with some new spark plugs and wire(burnt #5,6). It was running real good and I was checking the guages out of random and noticed there was no oil pressure. We got beack to the house and drained the oil and found metal peices in it. So my besr guess is that it through a rod or bearing. Well While the motor is out of the car were going to go ahead and put some forged pistons and rings and might stroke it if money permits. We'll see, just kind of disapointing thats all.