New to the computer tuning and need help.

[91z24audio]

Ok as the title says.I am new to all this.I am primarily focus on doing my own tunning on my 91 Z24 5 speed.So far I have figured out I will need a Prom Programmer,replacement Proms,and Prom editor programs.one of my big questions is can I remove the EGR from the tunning when I swap to my 2000 3100 topend?Another is will I be able to remove the speed governer?How much flexiblity would I have with the prom reprogramming ?Thanks

[Mechanic]

Re: New to the computer tuning and need help.

can I remove the EGR from the tunning when I swap to my 2000 3100 topend?

Just set the EGR enable temp to a value higher than that which the motor could ever achieve (i.e. FF hex which equals 151° C).

Another is will I be able to remove the speed governer?

Set the values for the speed limiter constants to FF hex (255 MPH), which disables the speed limiter function.

How much flexiblity would I have with the prom reprogramming ?Thanks

More than you will ever need.
GMPCM includes the $A1.pcm definition file in its Evaluation Edition loaded with the BFUZ3200 binary. Since the BFUZ3200 binary code is appropriate for your application, you would not even need to register the software in order to accomplish your goals.

[SappySE107]

Why is it BFUZ3200? I thought the speedo code changed from 91 to 94 for the 5 speeds as well. I only know that the J bodies have issues with using different year chips compared to the wbodies which are ok with a broader range.

Your best bet is to use your stock code as a base for tuning. You can copy some of the code from BFUZ though,or possibly just use BFUZ and copy the stock code you need to make it work right.

[Mechanic]

BFUZ3200 supersedes "all" Federal emissions manual trans $A1 binaries.
It was issued to address technical bulletin 336506 (PROM - Stalls, Long Cranks/Idle/Decel Surge). The changes to the code made to address this TB were "quite" extensive, and therefore not something easily transfered to the previous outdated code.
The BFUZ3200 is therefore the logical selection one would make if they were searching for a perfect starting binary for an A1 manual trans application. And should be considered even for a stock upgrade to your existing code.

Some interesting reading on why opting for the BFUZ code among other choices is a rather good idea :

http://www.misterfixit.com/336506.htm

[SappySE107]

Are there 2 BFUZ codes then? The one I have wasn't 3200 for the 4 numbers after BFUZ. I know there are 2 BCFA codes. I have tried BFUZ in 91 cars and it didnt work at all to even run them. This is of course j and l body only. Thats why i believe there to be another BFUZ if this is in fact the case.

[Mechanic]

No, there is actually only one. The naming convention we use is the Broadcast Code (BFUZ) followed by the EPROM ID (3200). There are common occurances where the Scan ID was substitued for the EPROM ID, or even binary file names referenced by BCC alone. However, they all refer to the same binary file.

It is possible that you obtained a corrupted file, or even one that had been previously modified. The authentication system software we developed helps us to ensure that file integrity will not be problem for our users.

[SappySE107]

Odd, cause I havent had much luck with BFUZ in 91 5 speed 3.1 J and L bodies.

[Mechanic]

The breakdown for the technical bulletin replacement was as follows :

1991 L-body
1992 L-body and J-body
1993 L-body and J-body
1994 J-body

All were 3.1 MPFI V6 Vin T, Federal Emissions, with 5-spd (MG2) manual trans.

[Cliff8928]

1991 was the last year for that POS of a VSS in the J-Bodies..


Cliff Scott
89 BerettaGT
89 Volvo740

[91z24audio]

Cliff are you refering to the Vehicle Speed Shutoff or the Vehicle Speed Sensor?The speed shut off is still on the 94 Z24 3.1 5 speed cars,I have one of those too.The speed sensor is also present in 94.

[bszopi]

He is referring to the speed sensor. All cars have them, but the J-bodies recieved a new design in 92.

[Cliff8928]

Yeah, the VSS in the 91 and older J-Bodies was driven via a nylon gear, where about every other car had a hall-effect magnetic type VSS a few years earlier at least..

Cliff Scott
89 BerettaGT
89 Volvo740

[Chris88CL]

Alright is there a book I can buy or some place online that will explain all the values in GMPCM that I can mess with? I understand alot of it, but not all. And I'd like to be able to "unleash" the full potential of this program when I program my chip. Things like "Spark reference angle" confuse me. Im a n00b , go easy on me.

[Mechanic]

No specific book has been published that would address all of the elements of eprom binary code modification, but there is still plenty of info available on the web. You may want to check the reference area in the GMPCM website links section, as it has a good selection of information links that you may find to be of value. And of course, to answer your specific tuning or GMPCM software questions, there is the Powertrain Control Module Technology board located on the GMPCM website. Answers to questions such as this are typically received within minutes of posting.

Reference angle is a point of crankshaft rotation, which of course is dependant on the type of engine. The reference angle for a 90 degree V6 would differ from that of the 60 degree V6 for example. One may want to think of it as a reference to the top dead center notch on the balancer if you were using a timing light. Although you can plainly see the notch, the PCM has no idea of where it is unless you tell it. Other timing values in the code are typically just adjustments based on the reference angle, with advance being added to the reference value, and retard subtracted.

Many items in the binary code such as reference angle are just settings that you need not be concerned with, if you consult the internet tuning resources I mentioned above, you will likely be pointed in the right direction as to which areas of the code you actually need to deal with in your tuning endeavors.

[Chris88CL]

Thanks alot. Posted on the GMPCM board.