Cyl#1-2 injector prob.

[BIGBRUDDA]

R/T and I have been "consulting" on the resurrection of an 86 New Yorker T1 car.
The problem is #1-2 cyl injectors don't fire. So far we tried 3 different Logic mods. 3 Power mods, and different injectors.
We've verified all the wiring between LM and PM, and injectors. Grounds are good, and we bypassed crunchy plugs and connectors.
I get NO injector signal from the 1-2 circuit(wht wire) output @ the PM.

ANY IDEAS?(seriously not rhetoricaly!)

[risen]

R/T and I have been "consulting" on the resurrection of an 86 New Yorker T1 car.
The problem is #1-2 cyl injectors don't fire. So far we tried 3 different Logic mods. 3 Power mods, and different injectors.
We've verified all the wiring between LM and PM, and injectors. Grounds are good, and we bypassed crunchy plugs and connectors.
I get NO injector signal from the 1-2 circuit(wht wire) output @ the PM.

ANY IDEAS?(seriously not rhetoricaly!)

Have you verified that those 2 injectors have power when the car is running (or cranking)?

I'd try to backprobe and ground the control line for that injector circuit from the LM at the PM with the car running/cranking (or with the injectors powered). You should hear the injectors click. Don't leave it grounded too long, a split second is enough.

If they click, then the problem lies with the LM or the wiring between the LM and PM. If they don't, the problem lies with the PM and the wiring between the PM and the injectors.

[BIGBRUDDA]

Yes we have. With both a VOM and blinky lites. Get a Voltage modulation (12-8) for first 10 sec, when cold. then nothin.

[turbovanman²]

Could be a ground issue when it warms up.

[risen]

Yes we have. With both a VOM and blinky lites. Get a Voltage modulation (12-8) for first 10 sec, when cold. then nothin.

So is this the power side of the injector that modulates or is this the output from the PM to the ground side of the injector?

[BIGBRUDDA]

output (wht) @PM connector

[BIGBRUDDA]

Could be a ground issue when it warms up.

not warm engine. But after 10 sec of cranking engine.It then goes dead for varying time periods.

[black86glhs]

You should try running a jumper wire between the injector harness and the pm. You could have a wire that is broken and making contact randonly. Rule out as much of the original wire as possible. I did this to an IAC once and it found the problem, broken wire.

[BIGBRUDDA]

Already done that, no difference

[black86glhs]

damn.

[risen]

IDK what it could be other than wiring if you've tried different PM, LM and injector combinations and all do the same thing. You tried with known-good LM/PM/injectors, correct? Wiring is the only thing you haven't changed. I'd check the resistance of all the wires going from the PM to the injectors and from the LM to the PM.

The only other thing I can think of, if all the wiring and electronic parts are OK, is maybe the fuel rail has some blockage of some sort. That's a stretch, but I guess it's the only other thing to change.

[GLHSKEN]

Use a different harness. I back the broken wire conclusion...

[BIGBRUDDA]

We've"rungout",or Ohmd all the wiring tween LM and PM, And Pm and injectors. All under 1ohm.
I'm now wunnerin bout the injector "sync" signal. Which is generated I believe in the HEP. Any thoughts?

[risen]

We've"rungout",or Ohmd all the wiring tween LM and PM, And Pm and injectors. All under 1ohm.
I'm now wunnerin bout the injector "sync" signal. Which is generated I believe in the HEP. Any thoughts?

You can check the input for the injectors at the PM. The LM should be pulling the injector input pins on the PM to ground. I'm not sure what the max current you can put through them is, but I've done 15ma (through a LED) repeatedly with no ill effects on the bench. You should see a evenly-timed pulsing of the led.

[black86glhs]

Have you pulled the cap, rotor and HEP and looked at the distributor? Maybe change the HEP just to make sure it isn't it. Plus it is easy.