The reference was to the actual fuses. Sometimes they look fine when they're not.
Each bank of injectors is getting power. Individual injectors are not, so the problem can't be with the fuses. The circuits are grounded by the ECM. Continuity is lost near the injectors somewhere. The wiring diagram just shows you the single wire that powers each bank and then goes back to the ECM.
Each bank of injectors is getting power. Individual injectors are not, so the problem can't be with the fuses.
Three injectors aren't working. True, they're not all on the same "bank" (and/or same side of engine), but it might be possible for both injector wiring harnesses to each be connected to one of the "wrong" injectors (as the injectors are all relatively close to each other). So if one fuse was burned out, two injectors on one bank and one on the other wouldn't work. And remember, all injectors (are supposed to) fire at the same time, so it's not like the injector wiring harnesses need to be connected to specific injectors.
[EDIT] I just had a look at some photos I took of my Formula shortly after I had acquired it. In this shot, after I had pulled the upper intake manifold (to change injectors), observe the injector harnesses. It looks to me like one harness is servicing injectors # 1, 2 and 4... and the other harness is servicing injectors # 3, 5 and 6. Strange, since yes, you'd think each harness would service injectors # 1, 3, and 5... and # 2, 4, and 6.
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Originally posted by Dwayne:
thinking... do injectors 1,2 & 4 use the same wiring? when I test them for spark there is really no difference in the idle. when I test 3,5 & 6 it runs really bad
Dollars to donuts, Dwayne's injectors are connected the same way as mine were... and one harness "bank" of his isn't working. Could still be something as simple IMO as a blown injector fuse.
[This message has been edited by Patrick (edited 01-11-2020).]
As it makes no performance difference where any of the wires go, they just got bored on the assembly line and plugged the harness wherever. hmmmm.
The car left the assembly line in 1988, and I saved it from oblivion in 2013... so there were 25 years for someone to be screwing about with the injector harnesses.
so after a break from working on the problem I just getting back to it.
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I just had a look at some photos I took of my Formula shortly after I had acquired it. In this shot, after I had pulled the upper intake manifold (to change injectors), observe the injector harnesses. It looks to me like one harness is servicing injectors # 1, 2 and 4... and the other harness is servicing injectors # 3, 5 and 6. Strange, since yes, you'd think each harness would service injectors # 1, 3, and 5... and # 2, 4, and 6.
I did look closer to the injector wiring and they are wired like in the pic above...1, 2, & 4 together and 3, 5 & 6 together. I was going off the wiring diagram the whole time which is not representative of mine. originally I didn't want to mess with over 35 yr old taped up harness and possibly creating another problem.
So looks like a bank problem. I not sure how to troubleshoot it but I got 12v at all 6 injector connectors and 12v at all 4 grounds with key on. wanted to test with noid light to see if I get a pulse while engine was running but cant with intake off or in the way of accessing connectors. So I inserted the noid light into each injector connector and with key on or off and i cant get the light to come on at all? tried cranking engine and nothing. what does this tell me or what am I missing.
The ECM fires the injectors by grounding them. According to the wiring diagram above.....there are 2 ground wires coming out of the ECM, black and tan, both grounded at the same spot...I think it is a bolt in the sheet metal under the armrest.....check to see if it is all still good. If that all checks out, I'd guess the ECM needs replacing.
