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Guest Anonymous

programming your own GM EPROMS...

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Careful, it's easier than editing 1 and 0s but still a bit harder than some of the aftermarket stuff. I've been looking into this a great deal lately (other threads - think Optispark) but have been looking at the flash programmable units so every change doesn't require pulling a chip. If you've ever programmed an aftermarket EFI system imagine trying to do it swapping CHIPS after every single change icon_eek.gif The LT1Edit stuff and Tunercat allow you to modify the flash programmable ECU much more easily. Not quite as on the fly as the aftermarket stuff but...

 

Suggest anyone interested in this also check out this site -> http://www.diy-efi.org/gmecm/ Those guys know the systems inside and out but read the archives before posting or they'll bite your head off icon_eek.gif I'm considering seeing what they think of my 94-95 ECU idea. Older GM computers were all batch fire and most were MAP based. The later 94-95 (OBDI) were full sequential and MAF based. MAF may not be as big an advantage as I'd thought though, I'm still researching.

 

The older systems work well though and they're pretty well known. You could have a lifetime of fun tinkering with them for cheap icon_smile.gif

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"http://www.diy-efi.org/gmecm/ Those guys know the systems inside and out but read the archives before posting or they'll bite your head off" You've been their too eh;^) If I was an EE it might be easier but it's 99.9% hebrew to me over their.

 

"The older systems work well though and they're pretty well known. You could have a lifetime of fun tinkering with them for cheap"

 

I recall one can build a setup such that you can flash to update/program a TPI type setup but it takes a little more legwork initially.

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Talked a little with the local tuner about some of the PROM systems. I think he was a little surprised I knew as much as I do about them. Realize you must burn a PROM for EVERY single change icon_sad.gif Also worth noting is that if I get this setup working using LT1Edit I might have to pull over for all change uploads. That's a downside but not quite as bad as swapping an EPROM. Unless of course the upload goes bad and the ECU is toasted (shiver).

 

Hrmph, we need an EFI forum icon_smile.gif

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Guest Anonymous

Thats a flash type prom right? I think your right, pull over, may need to turn it off and then just to ignition and then can you upload as I understand it, still better than burning proms... Glad your considering this, save us all some money after we find out what works and what does'nt icon_biggrin.gificon_biggrin.gif

 

Regards,

 

Lone

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I'm up late working on EFI specs for various aftermarket systems. The Holley really does look pretty impressive and the DFI GEN7 darned amazing. Will try to price out what an OEM flash programmable setup would cost too - I've got a bad feeling it's NOT competitive. Heck, just a new wiring harness is $600 from Painless! $250 MAF, $250 PCMECU (or more!), and each of the other sensors is $20-$50 bux. LT1Edit is something like $200 plus a $100 cable if memory serves. The MiniRam intake was over a grand with no injectors or TB. GM TBs are sick - $389?! I figure about $2800 w/no injectors or thereabouts? icon_eek.gif MiniRam too expensive?

Holley intake is $260 + $180 (!) or so for the rails I'm told. No TB or TPS there and carb style TBs from Force EFI are $525! Jeg's sells a NOS TB for a little over $600 w/Nitrous fittings. (sigh)

 

Comparison - Force-EFI sells a converted intake (Holley possibly) w/ECU (GEN7) and all sensors+ software for $2750 + $475 GEN7 "upgrade". This would possibly need a distributor. $3225 is darned close to the cobbled GM unit - sans the Opti stunts. Holley ready to roll system from Jeg's is what, $2400? And it would use my current distributor. Add to that $2400 some options for knock sensor and some little things though - can run NOS via computer which the OEM GM can't. GEN7 can run three stages icon_eek.gif

 

Anyway, I won't give it all away and I've not concluded anything yet but you can see why this is so hard! Once I've posted my research on my page I'll probably want some folks to help me double check it etc. too please....

 

P.S. Local tuner thought tyat a MAP system woudl require more tweaking, especially as weather changed. I don't understand this - weather changes shoudl be compensated for by the air temp tables and altitude changes measured with the MAP sensor. I don't want to dooubt him but this makes no sense and is partly why he likes MAF so much. Has suggested a Mustang EECIV as an option too. Prices on that are pretty cheap - wiring much cheaper!

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Guest Anonymous

Just to let you guys know, if you already didn't...there are quite a few companies making equipment and programs to burn your own eproms for GM equipped vehicles...mainly the 86 and up F-bodys, but also buick gns, cyclones, typhoons...Anyways, here's a good link http://www.thirdgen.org/tech/promintro.shtml

 

has a bunch of links in it to take you to the folks that make all the neat prom burning stuff...Looks REAL easy, and that's coming from me, so I know most of you guys can pick it up real quick...By the way, all the equipment costs about $300 bucks or so, about the price of a custom chips, and quite a bit under the SDS price, I believe...Download the tunercat program first, it's free, and you can get the free file thing for it, and see how easy this stuff is!

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Jim, I've made up my mind. If I had $2400 to drop on EFI, I'd just do the easy thing and buy the Holley Commander 950 MPFI. Sure others out there may be just as good for $2000 (Edelbrock Pro-Flo), or have better control (Motec), but staying below $2500 and having datalogging and laptop tunability are my requirements. But it's a HUGE chuck of change that I'm not willing to do at this point.

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I hear ya' Pete! The GM would have datalogging with the LT1Edit software. Diag light, MAF sensor, and factory service (lol).

 

The DFI GEN7 has nice things like a diag light that flashes codes and it'll compensate for errors. 3 stages of NOS possible too - maybe use those channels for other things?

 

Still researching, would help if the Accel site gave more info! FelPro, SpeedPro, and the unit sold by fuelairspark.com all appear to be the SAME unit. Goes under the SEFI8LO name too. Very confusing....

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