2005 LLY Duramax
12,500 miles
Predator (Currently back to stock tune)
MBRP 4" exhaust with cat delete
Fingerstick / Blocker plate

DTC Codes Set:
P1223
P0301

My truck started acting funny today on the way home from my holiday weekend. At first it started surging at about 50-60 mph, with a little stumble under light throttle. Shortly after, it began bucking really bad at every speed. I hooked up the Predator to check the codes, and there was a P1223 set. I cleared the code, and the truck ran good for a few miles, and then started surging again like it was doing at first.

I got it home, and figured I may have gotten some bad fuel, so I changed the filter, and when I started it up after the filter change, it was coughing really bad in the garage. I went to take it for a ride, and couldn't even get out of the driveway it was coughing so bad. It set another code, in addition to the P1223 this time it sent the P0301, which is a misfire on cylinder #1 code.

The balance rates looked like this:
14.XX mm Cylinder #1
-1.XX mm Cylinder #2
-1.XX mm Cylinder #3
-1.XX mm Cylinder #4
-1.XX mm Cylinder #5
-1.XX mm Cylinder #6
-1.XX mm Cylinder #7
-1.XX mm Cylinder #8

I'm stuck. I don't know what to do. It's not drivable right now. HELP!!

Any ideas of what I could do without taking it to the dealer? Will they hassle me about the missing cat, and will they be able to detect the blocker plate and finger stick? (they are installed very stealthily)

Thanks in advance!
Jeff

Cylinder #1 is out of spec. Sounds like an injector if you did the test procedure correctly.

I'm stating the obvious, but sometimes it helps to go over the facts and see what we can come up with.

It's obviously a fueling issue, as that balance rate is WAY out of whack, and it makes sense that improper fueling of cylinder #1 would cause the crazy surging and coughing.

Do you have an EGT gauge? If so, compare it's reading now at idle to previous readings. When an injector really starts pouring fuel, the exhaust temp should theoretically raise.

Are you getting any smoke--especially at idle? This could also be a sign of an injector that crapped the bed.

Finally, I'd check your oil and see if you're getting raw diesel in the crankcase. I also wouldn't run it anymore unless you absolutely have to because the bad injector is likely filling the crankcase with raw fuel...not a good thing.

I think you're right to just get it to the dealer...they have no reason to deny service based on the exhaust, and I really wouldn't worry about the EGR mods if they're tucked away neatly.

Hope this helps!

injector connector is broken inside of plastic,current fix is to replace the engine wiring harness

Thanks guys! Any more advice is greatly appreciated...

No, I don't have an EGT gauge, I couldn't really check for smoke last night (dark and rainy), and I'll check the dipstick tonight to see if it's making oil.

before you tow it,look carefully for bare wires where the harness is tie strapped to th eFICM bracket.remove the strap and pull the harness up to inspect.if so tape it up real good and your good to go

p.hinds, thanks for that info!! That's exactly what I was planning to do after searching around here some more and finding the thread with the info on #PIP3394A.

If they need to replace the injector wiring harness, what about my fingerstick??? Is that going to be a problem? Should I remove it and try to cover any and all traces that I was ever in there?? What are the odds that I'll get f*$%ed on this deal?

Thanks,
Jeff

Oh yeah, and where is the FICM located?

Thank you!

pssenger side front of engine,look for fuel lines and electrical connectors to it.flat and square shaped.where the wires come from the FICM,they are tie strapped to the bracket maybe 5 or 6 inches from the FICM.the bracket will rub thru the wire protection,you wiont see bare wire hanging out,youll have to look carefully probablt with a flashlight.

Green Chevy didnt hassel me about my exhaust, they seemed pretty cool about the whole deal. On a LB7 is the electric box gizmo on the pass valve cover and it has a fuel line foiung in and outa it. a little warning sticker about not pressure washing it too I believe. I'm sure you will have it taken care of by this weekend but leme know if you need a hand, I will be up this weekend....

mounted above front of right side valve cover,easily accessed

FIXED!!!

This was the problem
http://www.dieselplace.com/forum/showthread.php?t=30336

Thanks DieselPlace!!!!

If you haven't checked this already, by all means, do so!

:clap: :clap:

Thanks everyone, especially p.hinds, you're definitely on top of your chit.

Had the same FICM short 2 weeks ago. Dealed towed it and had it fixed right away. There's a TSB on it. Was pretty damn embarrasing to have to haul multiple loads of hay with the wife's Tahoe!

glad to here it was an easy fix,also thanks for posting that its fixed

Yeah, and the best part is that I didn't have to put my cat on again, or take out the blocker plate or fingerstick for a dealer trip.

The hardest part of the fix was the trip to town to buy liquid electrical tape...:eek: