Hey, Tom Hendricks

[James W.]

Tom, during a PV on a 1990 ZR-1, would an aftermarket chip cause it to fail? I have the original chip, but there are issues with it, which is why GM issued a revised chip. Just want to be ready for October

Jim

[Tom H.]

Re: Hey, Tom Hendricks

Hi Jim !

Good question. One that I cannot answer 100% for you. I would think if the new "chip" does not change the way the car performs during the PV it would go undetected and would not keep you from passing.

Perhaps someone who has judged these or knows of something that would make this an issue will also chime in.

My answer for now would be that it should not cause you to fail. I will look into this further when i get into the office tomorrow.

[Tom H.]

Re: Hey, Tom Hendricks

I just located an original 90 prom that I have here in my desk. If you decide you need an original to pass, I would be happy to send it to you to use.

[James W.]

Re: Hey, Tom Hendricks

Tom

I appreciate the offer, but I do have the original PROM. I'm just not sure what it would do to cause the car to fail. It's bascially the same as the GM updated PROM to resolve radiator fan operation and CAGS issues

Jim

[Gary J.]

Re: Hey, Tom Hendricks

Why not contact and the Team Leader to know for sure, then there would be no surprises.

[Darrell S.]

Re: Hey, Tom Hendricks

You may want to contact Tom Barr He is the team leader for 1990-1996.

[Peter M.]

Re: Hey, Tom Hendricks

The OEM prom controls many, many engine operational related issues to include the temperature at which the engine cooling fans come on and go off. If any of these many engine control setting are significantly different from the OEM chip, you may have trouble.

Seems to me that the first thing you need to know is in what way does the after market chip differ from the original. The chip supplier should be able to provide this information, or at lease point you in the right direction to get it. You can then decide exactly what your PV exposure might be.

Unless your OEM prom causes you noticeable operational problems, your best bet might be to reinstall it for PV purposes.

[James W.]

Re: Hey, Tom Hendricks

I've exchanged my PROM so I shouldn't have any issues with the PV. I think most of what it does is to correct the same issues GM addressed with their updated PROM. I think it changes cooling fan cut in and out temperatures, resolves an issue with idle after high-speed driving and uneven idle. I've been looking for the sheet that came with the PROM, but having recently moved it is eluding me. Also, I was thinking of a froend of mine named Hendricks when I meant Barr. Old age can be a terrible thing

Jim

[Peter M.]

Re: Hey, Tom Hendricks

I've exchanged my PROM so I shouldn't have any issues with the PV. I think most of what it does is to correct the same issues GM addressed with their updated PROM. I think it changes cooling fan cut in and out temperatures, resolves an issue with idle after high-speed driving and uneven idle.
Jim

Yes, this is the issue at hand. If your after market prom has the fans coming on and off at different temps than are specificed in the PV manual, then you may have a problem passing the PV.

If you are unclear as to what exactly your after market chip does, perhaps you should take up Tom Hendricks' fine offer and install the OEM chip that he has offered you. Just a thought....

[Ed H.]

Re: Hey, Tom Hendricks

You may also have a problem with the slow speed 1-4 shift. I know some aftermarket chips (Texas Chip) does away with the 1-4 shift.

[James W.]

Re: Hey, Tom Hendricks

Sorry, gentlemen. I reread my last post and guess I wasn't clear. I have reinstalled the original PROM, which I had. Not that big a deal to do, as it's pretty easy to get to. I appreciate the insight as to the the different aspects of the PROM and replacements. See you in Frisco????

Jim