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Discussion Starter · #1 ·
I am installing '75 efi into a '72 Manta. i am finding that my Opel memory has many holes. Two questions. It seems that the cover for the thermostat housing is different on the '75 if this is the case does anyone have one for sale? Also, the EFI harness I have only has one connector for the dual relay. Where does the other connector come from? Is it part of the main harness? I do not remember what I did when I converted my '74 to EFI back in the 80's. I can wire it in via the wiring diagram if I have the connector. Any help would be appreciated.
 

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Should have two plastic white square connectors?

From what I know my harness has two platic white square connectors and yours should also if it's a 75 harness, if not it's a later European wiring harness I think??? As they went to one rely in the later model I beleive. David 27, otto and Kwilford are good ones to reply!

And thought to add check the forums under factory fuel injection, do your own home work when possible as this thread could be gone from the main page in two days.

Bummer I know but if you read enough you could be just as confused as you started out to be, or you maybe could find your answer sooner!

Regards,
Rick
 

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Discussion Starter · #3 ·
Ok, with a little help from soybeans L-jet infolmation in the gallery it looks like I am missing a small harness that goes between the dual relay/control unit/starter/and coil. Does anyone have one of these harnesses stashed away? I could make one up however I would prefer an OE harness.

So I would like to purchase a spare '75 auxilliary harness and a top for a '75 thermostat housing (where the upper radiator hose goes).
 

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If your patient, try Opels Unlimited.

Todd at Opels unlimited has everything for the 75 F/I system, OGTS has lost interest in these parts. Good luck getting a hold of Opels Unlimited however!


Regards,
Rick
 

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Discussion Starter · #5 ·
Aarg! Thread jacked! Back to our regularly scheduled program.
 

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IT Manta said:
Aarg! Thread jacked! Back to our regularly scheduled program.
Well, I un-thread-jacked it, by splitting the off-topic thread on its own. And while I was at it, I moved your thread that was posted to the "Mechanical" Forum (where almost NOTHING ever deserves to get posted to) to the correct Forum. So the world is right tonight...:)
 

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rangerrick said:
Todd at Opels unlimited has everything for the 75 F/I system, OGTS has lost interest in these parts. Good luck getting a hold of Opels Unlimited however!
Regards,
Rick
You might also try David Ponder at http://www.opeljunkyard.com/ (email is info"at"opeljunkyard.com, phone (606) 787-9847 in Yosemite, KY). He has quite a lot of Mantas and Asconas, and has been a big help to me.
 

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Discussion Starter · #8 ·
Thank you Keith, I have an e-mail into him. I hope this pans out because I am running out of options.
 

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Harness sighting on ebay

IT Manta said:
I am installing '75 efi into a '72 Manta. i am finding that my Opel memory has many holes. Two questions. It seems that the cover for the thermostat housing is different on the '75 if this is the case does anyone have one for sale? Also, the EFI harness I have only has one connector for the dual relay. Where does the other connector come from? Is it part of the main harness? I do not remember what I did when I converted my '74 to EFI back in the 80's. I can wire it in via the wiring diagram if I have the connector. Any help would be appreciated.

There's a F/I harness on eaby right now with a rusted looking relay attached
Item #4532114318

Regards,
Rick
 

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Discussion Starter · #10 ·
Thanks Rick. That is the harness I already have. If you look closely that harness only connects to one half of the dual relay (the rusty one). The other half comes either from a small auxilliary harness or is part of a 75 only engine/chassis harness. I do not have a vehicle to compare with. Either way I have pretty much decided to eliminate the relay all together and power the fuel system and pump via a seperate switched circuit. This is for my race car and I already have the circuit in place from the Carter electric fuel pump I was using before
 

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Discussion Starter · #11 ·
One last request before I pull my hair out. :mad: I am trying to wire the side of the dual relay that goes to the fuel bump, ignition switch, starter, coil,ground, and the battery. The problem I am having is identifying which terminals on the relay goes to what components. I have a Bosch book that gives relay number coding, but I have not been able to make the relay work properly. Could someone with a '75 tell me what color wires go to each numbered connection on the dual relay?
 

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dual relay

88d- to fuel pump (+)

86a- from starter solenoid

88y- from fuel pump fuse (+12v supply for fuel pump and aux air valve)

85- to ground (-)

86c- from ignition switch (+12v supply when ign is in "on")

88z- from battery (+12v supply for the computer and injectors, can be "always on")

88b- to terminal 43 on the injector pre-resistor (+12V to the injectors fia the resistor pack)

87a- apparently not used

86b- to pin 20 on the computer and terminal 36 on the air flow meter (maintains the fuel pump running after the engine is started)

88a- to pin 10 on the computer and terminal 39 on the air flow meter (+12v to the computer when the ignition is on and the +12v to the air flow meter switch for maintaining the fuel pump running)

86- to terminal 45,47 on the cold start injector and to pin 4 on the computer (tells the computer the engine is cranking over via the starter, and starts the cold start injector firing)

88c- to terminal 48 on the auxiliary air valve (+12v when the fuel pump is running to the aux air valve, grounded out through the computer when it needs to open)

That should get you going, but you probably need to get a '75 factory service manual suppliment before you go much further, it covers all the EFI stuff you are dealing with.
 

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Discussion Starter · #15 · (Edited)
Thank you very much Stephan. That is exactly what I needed.

Thank you also Jarrell. I do have the wiring diagram, but they do not show what nuber wire goes where or what wire goes to what terminal on the relay. Also I had no pinout for the ECU that showed what each pin at the ECU does. I was just one step short on information either way I wanted to figure it out.

I overlooked one page of the supplement that had the wiring diagram. Figures, the page I needed.

Thanks again for the help, she should be runining tomarrow :)
 

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Discussion Starter · #16 ·
I just wanted to thank everyone for thier help again. After finding my spare dual relay The Manta fired right up. New 1.9l EFI ITB engine ready for break in and dyno tuning. I also recieved my '75 supplement today, so I am all set . The car is just a paint job away from track ready again. All new suspension, rebuilt trans, brakes... I will post pictures after the pain t is done. The livery will be silver '75 GTE.
 
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