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I do know that the 8 injectors fire in groups of 4 with this system. I know Bruce Roe posted the injector groups before but I couldn't find it quickly. I did find the following which I think we can use/ translate because we know the firing order 1-8-4-3-6-5-7-2. He wrote "The Cad 79 system used 2 banks of 4 port injectors each, alternately fired on alternate crank revolutions by special HEI reed switches."

So I guess that means if we use "up"/ "down" then if 1 &2 are up 3 &4 are down 5 & 6 up 7 & 8 down. I may not be thinking this throw thoroughly but it seems like that would mean 1, 2, 5, & 6 would fire together and 3, 4, 7 & 8 would be the other group. If that's true could your "4" above be "2" or are those 2 connectors swapped?

Scott
 

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They are swapped, and no pulse even with them all unplugged. Looking for ECM pinout now. I assume the same ECU power source drives both banks, so it is either ECM internal or pin or wiring to that bank.

I'm looking for those answers in diagrams now.
 

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You can barely distinguish the wire colors, but they are swapped.
I have not found the ECM connector view/pinout yet.
 

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You can barely distinguish the wire colors, but they are swapped.
I have not found the ECM connector view/pinout yet.
I found the diagram on the site you shared with me. As far as I can tell, it's not two separate power supplies to the ECM, so I shall check the pins at the computer.

Thanks. Alldata definitely did not have the diagram (though their library might have, if I asked.)
 

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I do know that the 8 injectors fire in groups of 4 with this system. I know Bruce Roe posted the injector groups before but I couldn't find it quickly. I did find the following which I think we can use/ translate because we know the firing order 1-8-4-3-6-5-7-2. He wrote "The Cad 79 system used 2 banks of 4 port injectors each, alternately fired on alternate crank revolutions by special HEI reed switches."

So I guess that means if we use "up"/ "down" then if 1 &2 are up 3 &4 are down 5 & 6 up 7 & 8 down. I may not be thinking this throw thoroughly but it seems like that would mean 1, 2, 5, & 6 would fire together and 3, 4, 7 & 8 would be the other group. If that's true could your "4" above be "2" or are those 2 connectors swapped?

Scott
Where do you recommend getting an ECM for this bird? I took it apart and saw nothing to solder, and no power is coming out of injector group one. All injectors ohm ok on both banks, at least with the engine cold. And there are no shorts to ground in the harness. Are these injectors known for shorting when hot but testing ok cold? If so I may suggest replacing them. The EGR passages are plugged, if he wants it perfect, I could take the manifold off and clean the passages and do the injectors at the same time.
 

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Thanks for the diagrams, the colors and pin letters were correct but the connector was on the end not in the middle as one picture said.
 

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Thanks for the diagrams, the colors and pin letters were correct but the connector was on the end not in the middle as one picture said.
ACTUALLY, I SEE THE STUFF YOU JUST SENT HAD THE CONNECTOR ON THE END, ANOTHER DIAGRAM I SAW EARLIER SAID IT WAS THE MIDDLE CONNECTOR.
I SAVED ALL THE STUFF YOU SENT IN THE CUSTOMER'S FOLDER. oops, caps. Thanks again.
 

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If you think it's the ECU Bruce Roe is 1000% the best person to send it to. I will send you a PM with his contact information. He does screen his calls, old school answering machine, but if you start speaking and he hears it he will pick-up. You can mention I recommended that you contact him.

He will check everything out and he will replace/repair only what needs repairing. He knows all of the common failure modes and he can bench test it to find issues. He's very reasonable. You can also mention what you've already found and see if he has any other ideas. The spare cores are not growing on trees but he suggested it's not a bad idea to carry a spare ECU. He does have some extras and if you ever come across non functional originals he can repair them. There are some foreign made replacements but when they go bad they are much more black box so those non-original are for the most part garbage.

Scott
 
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