GM '746 & '747 harness to megasquirt adapters
#1
GM '746 & '747 harness to megasquirt adapters
Just want to let folks know that there is now an alternative to burning eproms.... for tuning.
I designed and built an adapter board that allows the GM '746 & '747 TBI harnesses to plug directly into a megasquirt main board with no harness mod's. It all fits inside a GM '746 or '747 ECM case with a minor snip to get the laptop cable out the back.
This allows tuning on the fly with a laptop.
Note: there are a few functions not supported:
1) EGR valve operation.
2) speed referenced torque convertor lockup - this is done by MAP/RPM only.
3) until the MS2extra software is completed load based idle control is not implelmented. I cannot control if/when this will occur.
I designed and built an adapter board that allows the GM '746 & '747 TBI harnesses to plug directly into a megasquirt main board with no harness mod's. It all fits inside a GM '746 or '747 ECM case with a minor snip to get the laptop cable out the back.
This allows tuning on the fly with a laptop.
Note: there are a few functions not supported:
1) EGR valve operation.
2) speed referenced torque convertor lockup - this is done by MAP/RPM only.
3) until the MS2extra software is completed load based idle control is not implelmented. I cannot control if/when this will occur.
#4
Re: GM '746 & '747 harness to megasquirt adapters
#5
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Re: GM '746 & '747 harness to megasquirt adapters
#6
Re: GM '746 & '747 harness to megasquirt adapters
Thanks, I set the TBI up and go it running in about 30 min's after yanking the carb. This was the first test for the adapter board. This was to show the older inline crowd that tbi will work on an older motor.
The 292 that the test was run on is now with a new owner and an inline vortec 4200 has taken up residence.
The 292 that the test was run on is now with a new owner and an inline vortec 4200 has taken up residence.
#7
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Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
Re: GM '746 & '747 harness to megasquirt adapters
Thanks, I set the TBI up and go it running in about 30 min's after yanking the carb. This was the first test for the adapter board. This was to show the older inline crowd that tbi will work on an older motor.
The 292 that the test was run on is now with a new owner and an inline vortec 4200 has taken up residence.
The 292 that the test was run on is now with a new owner and an inline vortec 4200 has taken up residence.
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Re: GM '746 & '747 harness to megasquirt adapters
I've been thinking about this as well. Are you offering a conversion adapter or how to instructions? Let me know, thx
#12
Re: GM '746 & '747 harness to megasquirt adapters
Hi,
What I offer is an adapter board that one one side accepts the megasquirt board (direct plug in) and on the other side plugs directly into the GM '746 or '747 harness. This eliminates any harness mod's - plug and play. There are a few other parts on the board to interface MS to the GM scheme of things.
Let me kinow if this answered your question.
Marc
What I offer is an adapter board that one one side accepts the megasquirt board (direct plug in) and on the other side plugs directly into the GM '746 or '747 harness. This eliminates any harness mod's - plug and play. There are a few other parts on the board to interface MS to the GM scheme of things.
Let me kinow if this answered your question.
Marc
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Car: 85 camaro z28
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Re: GM '746 & '747 harness to megasquirt adapters
u wanna sell the adapter? also where did u get the stock connector to plug into the oem harness?
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Re: GM '746 & '747 harness to megasquirt adapters
Hey Marc, I am interested in this. How much? How long? What would you need from me? Thanks Jeff
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Car: 1991 Camaro Z28
Engine: L98 5.7 350 TPI
Transmission: Brand New (again) 700r4
Axle/Gears: GM 10 bolt 7.625 W/ TrueTrac 3.23
Re: GM '746 & '747 harness to megasquirt adapters
I'm sorry but what year do these ECMs come in? I have a 91 camaro z28.... will this adapter work for my car???
#17
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Re: GM '746 & '747 harness to megasquirt adapters
I have the TPI. Did they make the z28 with a TBI? Does the adapter work with my ecm?
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Car: 1985 Berlinetta
Engine: Megasquirted TPI
Transmission: Transgo 700R4
Axle/Gears: 3.42
Re: GM '746 & '747 harness to megasquirt adapters
Wow.
I am glad somebody finally came up with this board. Keep up the good work!
The Megasquirt is an amazing system, and you just made it that much easier for everyday folks to use it.
I am glad somebody finally came up with this board. Keep up the good work!
The Megasquirt is an amazing system, and you just made it that much easier for everyday folks to use it.
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#19
Re: GM '746 & '747 harness to megasquirt adapters
The later 89 and up TPI systems used the next generation GM ECM than the TBI motors - so sorry no its not compatible.
Could one be made for the TPI motors - yes - I would need to see enough demand for the board or do a one off which would incur a design cost. If say 30 people came and I want one - then no problem.
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Last edited by efi-diy; 02-03-2008 at 12:39 PM. Reason: Automerged Doublepost
#20
Re: GM '746 & '747 harness to megasquirt adapters
You can purchase the adapter board online here:
http://www.diyautotune.com/catalog/m...ter-p-187.html[quote=squirted1;3583881]Hey
#21
Re: GM '746 & '747 harness to megasquirt adapters
I know this is a really old thread, but is it possible anyone has these pics still or this info? I'm currently trying to figure out how to make this exact harness and this would be a GREAT BIG help! When I click the link to the imageshack photos non of them show up any more. Any help is appreciated.
#22
Re: GM '746 & '747 harness to megasquirt adapters
I know this is a really old thread, but is it possible anyone has these pics still or this info? I'm currently trying to figure out how to make this exact harness and this would be a GREAT BIG help! When I click the link to the imageshack photos non of them show up any more. Any help is appreciated.
Last edited by RBob; 02-12-2021 at 09:45 PM. Reason: No prices unless a sponsor, take it to PM.
#23
Re: GM '746 & '747 harness to megasquirt adapters
Sorry for the late reply, I just saw this. Yes, I am interested in this. You can PM me if you like with the details on how to proceed. Thanks.
#24
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