I am perplexed

[Bobbyjtsorey]

So, my issue is that # 5 fails a buzz test and when I start the truck it shuts that bank down completely. If I unplug #5 pin at uhvc harness the truck will run on 7 cylinders, i.e. won't shut the bank down so I know #5 is the problem child. While trying to figure out if its injector or harness side, I swapped pin 5 and 7. Originally #5 was the only problem on buzz test, now ever since the swap it has been #5 & #7 failing the buzz test. Move forward to a week ago I said let me swap #5 with #1 pin just to double make sure, so I did. NOW #1 #5 #7 ARE ALL FAIILING THE BUZZ TEST. *** IS THIS WITCHCRAFT. NUMBER 5 BUZZ TEST CAN BARELY BE HEARD SO ITS DEFINITLY SOMETHING IN THAT CIRCUIT. I took my IDM out and put in my dad's exact same truck and it ran fine. I replaced the #5 injector and engine harness. I checked the truck side harness for damage of any kind and cannot find anything wrong; I even did the tug test thinking maybe a wire broke internally. I did the ohm test at IDM and every circuit read 2.7. I checked every ground known to man. I have good engine ground as well as body and frame ground. I took out my tuner as well. I want to just order a IDM but dang it ran good in my dad's truck so that doesn't make any sense that it could be bad. What am I missing here? ALSO, UHVC GASKETS ARE NEW MOTORCRAFT GASKETS.

 

[Dirtleg]

I just went through something very similar in December.
Removed entire engine harness, all sheathing and even all the foil tape around the injector wires, and went through it wire by wire.
Also checked everything on the truck side to the IDM. All wiring good.

Got new gaskets, swapped to the later single plug style (my truck is a 95) and redid all the pigtails in the harness as well as all the glow plug wiring and even wrapped all the injector wires in new foil shielding.

I swapped my IDM into a friends truck and it seemingly ran well. Then I compared it to his IDM, and it ran better with his. (His truck not mine)

Everything ohms out fine in mine as well.

Even after all this it was shutting the drivers side bank down. On buzz test I see a #8 fault.

At the end of the day, I purchased a used IDM on fleabay and it fixed the issue of shutting down the left bank. It is still not running perfectly. I am getting faults on the #8 injector that I believe are related to a failing coil, but the truck runs on both banks at least.

I am getting ready to send my old IDM out for repair.

I cannot say for sure your issue is the same, but it seems to be similar.

Also my problems I believe were created when a squirrel munched on the injector wires and I tried to start the truck not knowing there was a short in the wiring. Pretty sure that's what messed up the IDM.

 

[Rdnck84_03]

@Dirtleg a failing injector can also take out the IDM.

James

 

[Dirtleg]

@Dirtleg a failing injector can also take out the IDM.

James

Good to know. I will make sure I address it before putting the truck back into service.

Apparently the truck ran well before the squirrel got it, at least that's what I was told, as the damage happened before I acquired it. So I naturally thought it was the crossed exposed wires that damaged the IDM.

 

[Rdnck84_03]

Im sure that would damage it also.

James