I am trying to program a 27c256 for my 165 ECM and have not been able to get a chip that works. I have the pocket programmer and I am using it on a Dell laptop running in MS-DOS mode. Fileprom says the prom is programmed and verified but I get a constant SES light and I can not link with Diacom. I am trying to use the ARAP bin, I have disabled VATS and changed the fan operation. This is a 88IROC 5.7 system installed in a 87 Monte.

The bin I am using is a 32K file made by copying my modified bin to another file name then combining the two. I have tried erasing the eproms for as long as an hour and so far no difference.

Thanks,
Dan

 

I'm haveing the same problem! I've tried burning the prom alot of differant ways, and haven't gotten it to work for me either. I've even tried the at29c256 flash chips. My ecm doesn't like the 256s. Works fine with the 128s though. I'm going to try another ecm before I give up on tring to use the 256s. Good luck.


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87 GTA 355/700r4
ported&polished 083 heads
xe268h comp cam
1 5/8 blackjack alumicote
homebuilt y pipe,pasesetter 3in mandrel cat back.
ported/manifold,upper plentum, tpis maf.
airfoil, 24# svo injectors, hypertech stage 3 chip, underdrive pulleys, erson roller rockers, chromemolley pushrods,2100 stall, shiftkit, 373 10 bolt.

 

Use two of the codes that your actually running.
Are you recalulating the checksum?.
Some GM eproms just never erase.

 

I have used several 256 chips on my 165 ecm with no problems. All you need to do is set the start point to 04000 in fileprom on the chip, and just burn the single image. No need to double it up.

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http://www.havemann.com/lee/firebird.html
1989 Firebird Formula, WS6 Package
ZZ4 Crate engine, Accel 24 pound injectors, Accel Superram intake, Accel Large tube runners
SLP 58 mm throttlebody, Edelbrock TES headers, SLP 3" SS exhaust, Random Tech 3" hi flow cat
700R4 trans w/ vette 2/4 shift servo, worked valve body, kevlar band, 2200 rpm stall converter
Borg Warner 9 bolt rear (full poly mounts) Hotchiss panhard rod, Lakewood LCA's, Spohn subframe connectors, custom chip.

 

There are a variety of ways to get the BIN in the top half of 256 for use with the 165. Offsetting by x'4000 seems to be the quickest way and usually works. "Doubling up" is the easiest way to ensure that you have a copy on the top half.

It think the biggest problem people encounter is the 16K MAF BIN ends up on the bottom half and something else ends up on the top half. It is the "top half" that matters when writing a 16K MAF BIN onto a 32K eprom.

Definitely make sure that the checksum is correct. It is must be the checksum derived by an Editor like TunerCat...not the checksum as derived by FILEPROM (or whatever program is burning the BIN onto the eprom).

 

Thanks for all the suggestions. How do I make sure the checksum is correct. I am using Tunercat.



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1987 Monte Carlo LS
357 TPI

 

If you are using TunerCat, then it is calculating the Check Sum properly. I find that TunerCat will recalculate the proper check sum EVEN if you have "manually" changed the BIN without adjusting the check sum. I do this when I modify the source code (for serious changes that affect the code) and then just read the compiled BIN with TunerCat to correct it.

 

I would like to thank everyone for their help. I changed the start address as recommended and now I am a prom burning fool. I have burned a chip and installed it and so far so good. I will take the car out for a drive in a little while and see how my changes work.

Dan

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1987 Monte Carlo LS
357 TPI