jpmountainboy

------Why I did all the grounds----
So I just went through and grounded the piss out of everything under the hood. My 3.4 swap still throws a circuit malfunction code on all the powered sensors (MAF, tps, 02), but only every once in a while, and they switch from one to the other.

The headlights would also dim when brake pedal depressed, so I figured hey, maybe its a grounding problem lets go through it.
-----Here is what I grounded------
All previous grounds were clean and with new wires after the swap. I had grounds from the battery to fuse block, to the engine block, and to th body. the grounds I added were from the engine to the frame, and from the frame to the body where the battery was already grounded, then from there I did a ground (blue wire in picture) connecting all of those to the ground point on the top of the plenum where the harness grounds attatch.
-----Here is what happened------
I hopped in the truck, idles fine, take off up the road, and as soon there is any load at above 2800rpm, it starts missing & bogging. I pull over and disconnect the ground that connected all the other grounds to the plenum/harness ground, and then she ran fine!!!???

------What does this Imply???-----

The only theory I can come up with is that the injector/coil pack grounds inconsistently & pull from longer and shorter ground paths, causing delayed firing.

Or is this pointing to a possible short somewhere?? Any insight helps. Thanks

jpmountainboy

anybody?

swampfox

did you ground the plenum ground wires to the battery? if so try putting the wires back to the original grounding point with the factory wires. there might be to much resistance in the circuit . it's just a guess.

thook

I'm a novice about wiring technicalities, but I like to read on this website under their technicle articles for info:
http://www.autoshop101.com/autoshop15.html


Read page 5....
http://www.autoshop101.com/forms/h25.pdf

tim a.

I think you need to take your test light your ground while its forkin up.Sounds like a backfeed issue.See if your ground circuit is picking up voltage while the engine loads and report back.