Question: I think my truck died last night :(

[Nevadahiroller]

So my wife drove my truck about 5 miles last night and on the way home, she called and said she thought it was in limp mode (wouldnt go over 15mph and would shift really hard into second gear). Anyway, she said there was no smoke coming out of the exhaust and no funny noises.

Anyway, I scanned the truck today and it threw dtc's P0300, P0301, P0304, P0306, and P0307. What I have searched on these codes wasnt good. They were all related to cracked pistons. Is it a for sure thing that I have cracked pistons or can it be something else?? Is my motor toast?? Time for a build??

Any help would be very appreciated. Thanks guys.

 

[dmaxfireman]

is your oil fill cap still on? any blow by?

 

[JD4440]

I thought white smoke from the tailpipe and blowby out the dipstick and/or filler cap were a given with a cracked piston ?

 

[McRat]

A cracked piston won't stop the truck from going full speed. It will make noise, smoke at idle, and blow the dipstick out under load. It's not subtle.

I don't have those codes memorized, so I'll have to look them up.

 

[McRat]

Those are miss-fire codes. Odd you aren't seeing smoke.

Lots of things can cause miss-fire codes. #1 on the list is injectors.

 

[RKTMech]

More info, is it knocking real bad, did you look at the exhaust during the day, check for the wire chafe area at the sharp edge of the alt bracket. Even if the wire is not rubbed thru the insulation all the way it can still cause running conditions.

 

[duratothemax]

injector harness I bet.

There is no such thing as a "cracked piston" code. Everytime ive blown up something big/serious in a duramax ive never had a check engine light or limp mode.

 

[RKTMech]

Yeah and with a inj grouping 1-7 and 4-6 look at all your wire connections and for rub thrus. Doubt you cracked or damaged 4 pistons going to the store. Have heard of a set of rods that didnt like to go shopping though..................:rofl:

 

[Nevadahiroller]

DURATOTHEMAX- Sorry about the confusion. The codes read as
P0300 Random/Multiple Cylinder Misfire Detected
P0301 Fault Cylinder A-Misfire Detected (CYL)
P0304 Fault Cylinder E-Misfire Detected (CYL4)
P0306 Fault Cylinder G-Misfire Detected (CYL6)
P0307 Fault Cylinder C-Misfire Detected (CYL7)
when I did a search on this forum about the codes, almost everything that I found was someone with a cracked piston. I didnt mean to say that it was a "cracked piston" code.

I haven't had a chance to check for smoke during the daytime yet but I will do that today. I will also check the injector harness for chaffing and the oil cap and dip stick. Thanks for the help. I will keep you all updated.




.

 

[Nevadahiroller]

Okay, I checked some stuff today.

Oil cap = Good, no blowby oil
Dipstick = Good, no blowby oil
Exhaust = No smoke at idle or while driving
Wiring harness = Looked and didnt see anything obvious

So I cleared the codes and took it for a drive. Didnt seem to have any problems at all.:dontknow:

I still need to check in connections at the injectors. Its probably the LLY Gremlins.

I did a search and couldnt find exactly where the harness rub problem happens. I know its near the alternator on a bracket but I couldnt see a whole lot since I am outside and its snowing (dont have access to a garage right now). So if anyone has pics of this problem area I would greatly appreciate them.

Thanks for the input.

 

[McRat]

IIRC, on some LLY's the head gasket protrudes from the block, and it's sharp. If the wiring harness is not located correctly, it cuts through the wires eventually. Make sure no wires are near the head gasket area.

 

[JoshH]

Look for the typical harness rub through at the FICM. That's what my money is on.