computer trouble please help

[fitz93z28]

installed new camshaft with a huge duration, and got lt1 heads ported and polished and added 1.6 crane roller rockers, lt4 intake and a larger throtle body, cars not running like it should took it in to the shop and the trougle code read something to do with the "quadjet" whatever that is, and people suggest to take it to have the computer burned, but i cant find a place that does it around in michigan. if you have a suggestions or know a place that will do the computer, please get in touch thanks

[Injuneer]

93's have several codes referenced as the "Quad Driver Module".... it should also have a number with it... e.g. Quad Driver circuit #1. You need that to know what the problem is. Just give us the DTC code.

Just curious.... how much machine work did you have to do to bolt your LT4 intake to LT1 heads? Do you have any dyno data to support the gain (or loss) from doing this?

[FRMLAV8]

Did you remove the EGR and AIR system from the car?

I just put a 383 stroker in my 93, and after we got it done we got a code like that. It was a quad driver something??????

Anyway it was because we removed the EGR from the car, but the guy that programmed my chip didn't turn something off in the ECM so it was still looking for the EGR. Our temp. solution was to plug in the EGR, or find out what resistor would work and stick it in to the EGR plug.

But what I would reccommend for you is swap to an OBD1 ECM, so you can have someone program the ECM with LT1 Edit or a similiar program. It was cheaper to do that than have to mail my chip back and forth 5 or 6 times to TRY to get the tuning right. Because the car is down for a week everytime I need to get the chip burned.

[fitz93z28]

egr

yes the air pump and all the egr was removed from the car

[FRMLAV8]

if you still have the egr sitting around, try plugging it in and reset the ECM. See if that gets rid of the code.

[Injuneer]

Originally posted by FRMLAV8

But what I would reccommend for you is swap to an OBD1 ECM, so you can have someone program the ECM with LT1 Edit or a similiar program. It was cheaper to do that than have to mail my chip back and forth 5 or 6 times to TRY to get the tuning right. Because the car is down for a week everytime I need to get the chip burned.

You can't just swap a 94/95 OBD-I PCM into the 93. There are too many differences.
-93 is batch fire, 94+ is sequential injection
-93 is speed-density, 94+ is mass-air
-93 ECM has no A4 interface for 4L60, 94+ requires 4L60E signals.
-93 uses single-wire O2 sensors, 94+ uses 4-wire sensors, with two wires to the PCM

A few other differences. A huge amount of work to change out the complete wiring harness, and change all the "differences".

I answered an e-mail from "fitz", because of his using the LT4 intake on the LT1 heads with no machine work. They don't fit correctly unless you machine the LT4 intake in the area where it interfaces with the valve cover rails. I suspect he may have a huge vacuum link.

There is also no evidence to support using the LT4 intake on LT1 heads. I know from my discussions with Pete at CNC Cylinder Heads that the LT4 intake has some severe compromises in it that were necessary to allow the LT4 to meet emissions. The intake will flow the 240cfm the stock LT4 heads require, but it does not respond well to increased head flow via porting. It takes an extensive amount of internal porting of the LT4 intake to support high flow heads. I have verified what Pete said on a flow bench, with the LT4 ported heads and ported intake I bought from CNC. I suspect there might be an additional incompatibility with the LT4 intake being designed for the raised runners in the LT4 heads. Not sure how they are going to work with the LT1 heads, even if they are port matched.

There has been extensive discussion of this on the LT1 Tech forum at CamaroZ28.com, and t+ requires 4L60E signals.
-93 uses single-wire O2 sensors, 94+ uses 4-wire sensors, with two wires to the PCM

A few other differences. A huge amount of work to change out the complete wiring harness, and change all the "differences".

I answered an e-mail from "fitz", because of his using the LT4 intake on the LT1 heads with no machine work. They don't fit correctly unless you machine the LT4 intake in the area where it interfaces with the valve cover rails. I suspect he may have a huge vacuum link.

There is also no evidence to support using the LT4 intake on LT1 heads. I know from my discussions with Pete at CNC Cylinder Heads that the LT4 intake has some severe compromises in it that were necessary to allow the LT4 to meet emissions. The intake will flow the 240cfm the stock LT4 heads require, but it does not respond well to increased head flow via porting. It takes an extensive amount of internal porting of the LT4 intake to support high flow heads. I have verified what Pete said on a flow bench, with the LT4 ported heads and ported intake I bought from CNC. I suspect there might be an additional incompatibility with the LT4 intake being designed for the raised runners in the LT4 heads. Not sure how they are going to work with the LT1 heads, even if they are port matched.

There has been extensive discussion of this on the LT1 Tech forum at CamaroZ28.com, and the consensus is that the LT4 intake is not the way to go with LT1 heads. I suggested a "search" for post by "Arnie", who has posted the specifics of the interference problems between the LT1 heads and the LT4 intake.

[Injuneer]

Another one of my posts (above) screwed up by the "board" duplicating the text and jumbling it all up....

If JR can't fix this, I think I might just stop posting here.

Fred

[FRMLAV8]

OH believe me I know that it is a huge amount of work, and there are some extra things that must be changed, but I was able to do the swap for about $600.

Which is worth it to me, because I can have my tuner sit right there and tune the car as oppsed to sending out the chip for a week at a time.

It does take more than just a harness and ECM, I wasn't trying to mislead him, I just didn't feel like typing everything out. I figured if he was interested in the swap, then I would give him the rest of the details.

Randy

[KnightFire]

www.pcmforless.com

Ask for Alvin, he has been burning my custom chips for awhile now and he is the BEST in the business! Let him know I sent ya.
He is overseas at the moment, but I'm sure his company will take care of you until he comes home.
Another place to contact him is at:
http://sdf.mogmhp.com/index.php (Speed Density Forum) He creeps around there all the time.

His commitment to customers is the best I've ever seen and I'm not one to give praise freely.

Now, what you need to do is get some sort of data logger, I prefer TTS DataMaster (free download 15 free data logs without purchase) you will have to get a OBDI ALDL cable from http://www.akmcables.com/ another outstanding company, run some logs and email them to Alvin, he will custom burn you a chip off of your data, and keep burning chips until your happy!

Your car DEFINATELY needs tuning...this is probably the quickest easiest route for us 93 owners with going to DFI or something of the same nature.


KnightFire