Whywhywhywhywhy

[DBUSHLB7]

Did you disconnect the main harness plugs on the drivers side of the motor? 2 bigger connectors that have the cam lock handles on them. If you did pull those apart to make sure you didnt accidentally roll a pin over somewhere. I have done this before and it caused me all kinds of fits. Good luck :thumb:

Great post. A month or so ago I had a bad fuel knock and two injector output circuit low codes. After speaking with a Colorado member here on DD's who is a GM tech, he advised me to disconnect the bale connectors and use needle nosed pliers to pull the male pins to re-seat them. Sure enough, 5 of them had become recessed and therefore not making good connection into the female side. Once pulled back into place (pins were now long enough to go into the female side far enough), truck ran perfect and codes have not come back! Don't know if this is just an LB7 bulletin but it couldn't hurt to try.

 

[Fingers]

What you said above is true of all the large connectors unfortunately.

 

[Hot COCOAL]

Good tip! Thanks guys, i probably would not have tried that on my own. I'll try tonight.

 

[1slowmax]

Not sure the model engine, but if you pressure washed and hit the FICM, you probably flooded the thing. The breather is not water tight. At least not from a pressure washer blast.

Its a LBZ, no FICM

 

[blk smoke lb7]

Your tune isnt going to magicly change because your batts were disconected.Did you check the grounds on both sides of the block?

 

[1slowmax]

Correct the tunes wont just change but if battery is disconnected long enough it will lose connection and ECM will lose all memory. If this happens the truck wont even start.

 

[adrenaholc1]

Sorry if I missed it but are the Batts fully charged? Also it seems like the electrical systems on these engines do some really weird things. For example when I was having a/c trouble last year one thing I tried was disconnecting the low pressure switch and jumping it with a paper clip to get the compressor running to check psi and add freon. Well after jumping that connector the truck went haywire and started acting like it was missing and threw some codes. That scared me enough to not mess around with the electrical shit anymore.

 

[Hot COCOAL]

Haha. Yea that doesn't sound like somethin id try...again, at least. I have pulled, cleaned and generally checked all the electrical connections, pins and wiring that i can see, without getting too carried away. I pulled my manifold off, instead of pulling an injector just yet, and the #8cyl was saturated with fuel???? That would be congruent with the 0308 code i got, why would it misfire? Improper timing? Broken injector body? WHAT IS THE SIMPLEST CAUSE TO A PROBLEM LIKE THIS? At least i know for sure its fuel not coolant, its fer sure the # 8cyl, there is fuel entering the cylinder. Duramaxtuner suggested it was an electrical issue, but offered no tangible help. I did not expect much being 2000mi away with no data log. So for now i have to put the manifold back on to fire it up and see if my last round of fiddling with wires changes the way it is running. Thanks again for the input all.

 

[1slowmax]

You could have just pulled the glow plug and saved tons of time. The glow plug goes directly into the cylinder on top of the piston. Sounds like cracked injector body like i suspected from beginning. Swap that injector and be done foolin around. Was probably just its time but i suspect you have something else going on. Balance rates would help. Keep us posted. Keep messing around and you could bend a rod or crack a piston.

 

[Hot COCOAL]

That is my biggest concern at the moment. I dont plan to mess around with it at all past this, i would just hat for it to be something i overlooked, or could have remedied on my own. Ill fire it tomorrow morn, see whats what

 

[Fingers]

Well, sounds like a stuck injector to me.

 

[JoshH]

Correct the tunes wont just change but if battery is disconnected long enough it will lose connection and ECM will lose all memory. If this happens the truck wont even start.

Hmmm. I've never even heard of this before. My personal experience disagrees with this. I had my LBZ disconnected for literally 14 months with no problems, and my boss had his LB7 disconnected for 12 months with no problems there either. I'm not sure how flash memory can erase itself because it doesn't have power to it.

 

[blackdirtymax]

Hmmm. I've never even heard of this before. My personal experience disagrees with this. I had my LBZ disconnected for literally 14 months with no problems, and my boss had his LB7 disconnected for 12 months with no problems there either. I'm not sure how flash memory can erase itself because it doesn't have power to it.

Agree with josh


Built motor , duel fuelers , big sticks , gtx4202r , and now a big brother

 

[VinceGU05]

did ya find the problem in the end? what was it?

 

[Hot COCOAL]

the COCOAL(d) truth

Results are in the thread, EMBARRASSING BUT SWEET RELIEF, started by me.

Long story short im an idiot, added an extra rag to plug off the exit side of the intercooler and forgot about it, started with 4 ended up with 5, removed only 4

MODERATOR, PLEASE CLOSE THIS THREAD

THANKS - COCOAL