GMP4 MemCal Hybrid Circuit Info

American Delco GM ECUs and PCMs, ALDL, OBD 1.5.
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GMP4 MemCal Hybrid Circuit Info

Postby Hogflash » Wed Jul 24, 2019 1:00 pm

I'm working with the Lotus M100 folks to come up with some replacement MemCals (ECM PN 1228707) but they are pretty much non existent at this point.

Does anyone here have any information or documentation regarding the design of the Hybrid circuitry in the MemCal and what all it controls (i.e. knock and limp home mode and other stuff?) I'm wondering if there is either a suitable replacement from a more popular vehicle, or maybe (given 25 years of advances in IC capabilities) a replacement could be designed. I seem to recall running across a project to do this many (10+) years ago, but not finding anything now.

Thanks,

Gary

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Re: GMP4 MemCal Hybrid Circuit Info

Postby delcowizzid » Wed Jul 24, 2019 7:03 pm

Should be a long memcal the same as 89-94 Holden Commodore but with different netres for limp home mode .here's the inside of one of the netres for number of cylinder select function and throttle body injection .we turn v6 ones into v8 ones and 4 cylinder and just leave the limp mode stuff as is viewtopic.php?f=11&t=214&hilit=Netres page 2 has all the possible combinations for cylinder selection.
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem

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Re: GMP4 MemCal Hybrid Circuit Info

Postby delcowizzid » Wed Jul 24, 2019 7:06 pm

Also the same as a all the usa long memcals from 1227165 747 etc
If Its Got Gas Or Ass Count Me In.if it cant be fixed with a hammer you have an electrical problem

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Re: GMP4 MemCal Hybrid Circuit Info

Postby Hogflash » Fri Jul 26, 2019 12:55 am

Has anyone actually traced out the circuit on the ceramic hybrid? This is what I'd like to see so I can understand what it is actually doing, and how to properly adapt it to different vehicles.

I have visually compared the M100 turbo and non-turbo circuits, and the non-turbo is a simple resistor network only, no active components. The Turbo is completely different and looks like the V8 version illustrated in the linked topic.

Gary

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Re: GMP4 MemCal Hybrid Circuit Info

Postby antus » Fri Jul 26, 2019 9:57 am

Does this help?
Attachments
memcal.pdf
(301.67 KiB) Downloaded 26 times
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: GMP4 MemCal Hybrid Circuit Info

Postby Hogflash » Sat Jul 27, 2019 12:31 am

YES!! Now *THATS* more like what I am looking for. This appears to be something used during development for the Lotus Carlton - I don't know what the similarities for the 4-cyl M100 turbo are, but it is a starting point. Now, to figure out what is in the Delco 26500 IC...

Thanks! --Gary

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