Start over,

[Tinbender59]

Joecar, I have been analyzing the poop!! out of this mess, and I think that I have a solid theory, if there is such a thing?

I have had the injectors out 5 times now, the last time i was kind of half paying attention to the seating of the bottom "O" rings. Now that I reanalyze (play it back in my head) i do not remember #7 seating! Maybe I'm making things up? But I will get into it and verify that all injectors seat without a doubt.

If I'm correct it would explain everything that I've been fighting, will not idle down, bad IAC codes, bad MAF codes, and of course the missfires at 2000 to 2500.

[joecar]

Sounds plausible.

When I'm not paying attention, stuff like that churns in the back of my mind, so I have to pull it all apart and redo it.

[Tinbender59]

Sorry for the long absence, my buddy had 2 rods start knocking in his 7.4 so we pulled it and refreshed it. Now I'm back on the trail of this missfire issue. I've moved coils, wires, #4 injector, still getting missfires on 4&7. I did reset the FPR to 58#, then vacuum referenced it (runs better). But still getting the same issue, 4&7??? Tomorrow, if the weather cooperates I'll check the wiring again. This is getting border line crazy!! Any ideas at all. I don't care how crazy it sounds at this point.

[Tinbender59]

Hum just watched a video. Spark plugs and may have an issue???

[Tinbender59]

I am getting a flashing CEL light, I am 3000++ missfires on#7, about 1/4th that on #4 in 6 miles. I did hear back fires in the LH head exhaust today. ( My exhaust pipes cross sides, the way I built it) I have swapped injectors, coils, wires, plugs, reverified coil and injector to ECM wiring compression checked it (150#) . Nothing effects it?? All I can come up is intake gaskets or a blockage in the intake??? Ya got any ideas??? I'm not sure if I want to keep this motor anymore��

[Tinbender59]

I am getting a flashing CEL light, I am 3000++ missfires on#7, about 1/4th that on #4 in 6 miles. I did hear back fires in the LH head exhaust today. ( My exhaust pipes cross sides, the way I built it) I have swapped injectors, coils, wires, plugs, reverified coil and injector to ECM wiring compression checked it (150#) . Nothing effects it?? All I can come up is intake gaskets or a blockage in the intake??? Ya got any ideas??? I'm not sure if I want to keep this motor anymore��

[Tinbender59]

My Dyno guy just told me that the injector connectors are a known problem on the LS style motors???? I guess I will be changing to EV1 injectors (I have a set of 36# "real" Bosh units, not the cheap knock off's) onwards I will trod. P.S. I do have an adjustable regulator, so I can drop the pressure to 45#??? If I'm remembering right???

[statesman]

P.S. I do have an adjustable regulator, so I can drop the pressure to 45#??? If I'm remembering right???

No, don't drop the fuel pressure... it won't help with the misfires.

[statesman]

I have swapped injectors, coils, wires, plugs, reverified coil and injector to ECM wiring compression checked it (150#) . Nothing effects it??

What plugs are you using now, and what are they gapped at?

What wires are you using now, and what are their resistances?

[Tinbender59]

NGK, I've had trouble with AC center electrode vaporizing, so I don't usually run them. I'll have to look at them for the number, I Gap at 0.045,. Resistance???? Hum?? Now that's an idea!!! I'll let you know.