How do you tell if your prom is stock? - ZR-1 Net Registry Forums

ZR-1 Mack · 12-15-2005

I'm pretty sure mine is stock, but the car does have a manual fan switch and remote access that are aftermarket so maybe the chip was also swapped out by the previous owner

Is there an easy way to tell if its stock ? I know the power key isn't bypassed but never thought to check until now.

Kevin · 12-15-2005

fan turn on, and CAGS are the most common changes

WB9MCW · 12-15-2005

take the unit off an turn it upside down and open the inspection lid and study it. Mine does a piggy back affair on top of the stock one, 90 degree to each other. because of the way the adapter fits in and the whole thing barely fits thru the portal. Now some chips are a complete repalcement so then the print on the chip will be ur telltail!!! let us know what u find. It is so great not having cags and esp. like having my fan come on at 180. my tunnel and under the hood temps are sooooooooo much better,, the stock 230 is nutz and was for the emissions testing...ur Z will be much happier at the new lower temps...ie mine on a 90 high humidty day will sit at 205 now after a 5 min stand still, now as i start moving again it will drop back to 180-185 while moving....much better..It's been sittin in my garage all last summer but I still plan to install the ...........................

http://www.c4orcecorvette.com/click here to go to BIG MOUTH AIR DAM SITE

tomtom72 · 12-16-2005

Hi Mack, I think the only way to know for sure is to R & R the ECM so you can flip it over to remove the "door" that covers the PROM & it's easy to read the mfg's name on it without taking the PROM out.

It is just like a RAM stick only thicker & it goes in a slot on the M/B w/locks just like a Ram stick. You shouldn't have to remove it to see who made it. The backside facing you, after you take the four 7mm bolts off & the cover plate & gasket is off, will have the "program code" I.D. like ABYK for the updated GM code for the 90's. If you go to Marc Haibeck's site the list for all the GM I.D.'s for the OE/ PROMs are listed.

Hope this helps.

Tom

WB9MCW · 12-16-2005

good post TT. He should be able to figure it all out now!!!

tomtom72 · 12-16-2005

Thanks Bryan! I'm just trying to carry on the tradition I learned from the senior guys about how we all help each other. Man, that's the best thing about owning one of these cars...the community is top notch!! The cars ain't so bad either

ZR-1 Mack · 12-16-2005

Thanks Bryan and Tom...will let you know what I find out right after Christmas. The car was an Arizona car so I think thats the reason for the manual switch.

But now I'm really curious because I never saw 230 last summer and was around 205-210 when standing still.

WB9MCW · 12-17-2005

my guess is that u got a mod chip already! Does the cags still function? cags is the 1-4 forced shift by solanoid activated shifting guide 1-4 gear for get this economy to make cafe etc. and avoid the gas g, tax! heywhatdidyathimk of the BIG MOUTH AIR DAM

bobbyhi · 12-17-2005

I think they look pretty cool. Probably going to order one. Does anyone have one installed?

RICHARD TILL · 12-17-2005

I`m Glad Cags Was Explained. I Wondered What That Was But Didnt Want To Expose My Ignorance.

12-15-2005	#1
ZR-1 Mack Join Date: Dec 2005 Location: Mid Hudson Valley, NY Posts: 72	How do you tell if your prom is stock? I'm pretty sure mine is stock, but the car does have a manual fan switch and remote access that are aftermarket so maybe the chip was also swapped out by the previous owner Is there an easy way to tell if its stock ? I know the power key isn't bypassed but never thought to check until now. __________________ ZR-1 Mack ... 91 ZR1 Black/Black #487 NY

12-15-2005	#2
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,632	Re: How do you tell if your prom is stock? fan turn on, and CAGS are the most common changes __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

12-15-2005	#3
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: How do you tell if your prom is stock? take the unit off an turn it upside down and open the inspection lid and study it. Mine does a piggy back affair on top of the stock one, 90 degree to each other. because of the way the adapter fits in and the whole thing barely fits thru the portal. Now some chips are a complete repalcement so then the print on the chip will be ur telltail!!! let us know what u find. It is so great not having cags and esp. like having my fan come on at 180. my tunnel and under the hood temps are sooooooooo much better,, the stock 230 is nutz and was for the emissions testing...ur Z will be much happier at the new lower temps...ie mine on a 90 high humidty day will sit at 205 now after a 5 min stand still, now as i start moving again it will drop back to 180-185 while moving....much better..It's been sittin in my garage all last summer but I still plan to install the ........................... http://www.c4orcecorvette.com/click here to go to BIG MOUTH AIR DAM SITE __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln Last edited by WB9MCW; 12-15-2005 at 10:22 PM.

12-16-2005	#4
tomtom72 Join Date: Dec 2004 Location: Jacksonville, FL USA Posts: 4,645	Re: How do you tell if your prom is stock? Hi Mack, I think the only way to know for sure is to R & R the ECM so you can flip it over to remove the "door" that covers the PROM & it's easy to read the mfg's name on it without taking the PROM out. It is just like a RAM stick only thicker & it goes in a slot on the M/B w/locks just like a Ram stick. You shouldn't have to remove it to see who made it. The backside facing you, after you take the four 7mm bolts off & the cover plate & gasket is off, will have the "program code" I.D. like ABYK for the updated GM code for the 90's. If you go to Marc Haibeck's site the list for all the GM I.D.'s for the OE/ PROMs are listed. Hope this helps. Tom __________________ 1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member

12-16-2005	#5
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: How do you tell if your prom is stock? good post TT. He should be able to figure it all out now!!! __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln

12-17-2005	#8
WB9MCW Join Date: Dec 2003 Location: McHenry, Il. Posts: 6,607	Re: How do you tell if your prom is stock? my guess is that u got a mod chip already! Does the cags still function? cags is the 1-4 forced shift by solanoid activated shifting guide 1-4 gear for get this economy to make cafe etc. and avoid the gas g, tax! heywhatdidyathimk of the BIG MOUTH AIR DAM __________________ http://i119.photobucket.com/albums/o...9mcw/SIG-2.jpg http://i119.photobucket.com/albums/o128/wb9mcw/vcm.gif "The Budget should be balanced, the Treasury should be refilled, public debt should be reduced, the arrogance of officialdom should be tempered and controlled, and the assistance to foreign lands should be curtailed, lest Rome will become bankrupt. People must again learn to work instead of living on public assistance." - Cicero, 55 BC " We the people are the rightful masters of both Congress and the courts, not to overthrow the Constitution but to overthrow the men who pervert the Constitution." - Abraham Lincoln Last edited by WB9MCW; 12-17-2005 at 12:22 AM.

12-17-2005	#9
bobbyhi Join Date: Jul 2005 Location: Mendota Heights, MN. 55120 Posts: 984	Re: How do you tell if your prom is stock? I think they look pretty cool. Probably going to order one. Does anyone have one installed? __________________ Bob Anderson 1990 #2405 White/Gray Haibeck chip,4:09 gears,Power Effects Exhaust,5 spoke chrome,C5 brakes,49th Street rockers,K&N,Hurst,Headers,Upper & lower ported Minnesota State Director Founding Member #19

12-17-2005	#10
RICHARD TILL Join Date: Aug 2005 Location: Iuka, Mississippi 38852 Posts: 756	Re: How do you tell if your prom is stock? I`m Glad Cags Was Explained. I Wondered What That Was But Didnt Want To Expose My Ignorance.