Great truck.......But!!

[MIKE MOG]

I took the trip to Hilton Head from Clevland and pulled distance for the first time. I thank everyone for the advise on OD lock out, It was great in the mountains, The truck is a 2003 d/a, crew cab with a 8 foot bed. Not pulling we got 19.5 mpg and in the mountains we did 12.5mpg. When we hit N Carolina and S Carolina We got 16.5 with the trailer on the back. I was impressed and the power was awsome. When We were half way through WV, I stopped on the Toll road to wait for my buddy. [He was towing with a 01 sub, with a 6.0].....LOVE THAT DURAMAX!!. Anyway, at that stop I noticed she was idling rough,I noticed real sharp and loud fuel knock. I took it to the dealer today. Any thoughts on what would cause this? I looked up a bullition at work today on rough running and it states to check grounds 102 and 106!! anybody seen this? Also I have posted in the past about a viberation at 55 to 64 mph. I found pip3239-[nov 16,2004] what do ya think? hope tohear from ya madmatt and MP.
Mike

[More Power]

Assuming the fuel filter has been changed and that there isn't an air entry problem, I'd look at injector balance - to see if there's an oddball injector acting up.

Any DTC codes?

MP

[MIKE MOG]

Hi MP,
fuel filter has about 4k on it and is the new style. Had no codes but you hit it right on the head, just got it back from the dealer and it neede a #2 fuel injector. has some oder in the oil but is not overfilled. IM going to change it this weekend. Thanks for the help.
Mike

[D-max Man]

Sounds like you are planning on changing it yourself. If you do, remember that on LB7 engines, the fuel lines that go through the valve covers are designed to vent externally in case of a leak at the fitting. Unfortunately this allows dirt to get between the fuel line and the nut. When you remove the lines, the dirt will fall into the top of the injector. You must vacuum the dirt out of the injectors before you reinstall the fuel lines.

DO NOT USE COMPRESSED AIR TO BLOW THE DIRT OUT!

This will cause some of the dirt to get lodged into the injector and you will have more problems.

[MIKE MOG]

Thanks D-MAX MAN But I still have some warrenty left. We sent it to the Chevy dealer. I will remember that when it comes time for me to do the repair.
Thank's Again!
Mike

[madmatt]

Hey Mike glad to hear you had a good trip! I just checked out that bulletin and think I'd hook up the trailer and give it a tug down the road. The vibration may have been caused by the injector wiggin' out the whole time although I haven't run into this, I wouldn't rule it out. Do you think you could get it to happen on a dyno??????

[MIKE MOG]

Hi Matt,
Glade to hear from you again. IM going to pull again this weekend, probably about an hr from hear into PA. Ill let ya know if its better. Only thing is I thought they would do all of the injectors per Doc#1566270. I did not want to push my luck at this dealership in fear of what the last one did when they found out I was a tech. Treated like *&^%!! Hows bussiness? Slow here.
Mike

[MIKE MOG]

Hey Matt.
I could probably get it to happen on the dyno with weight in the back, but where would I find a dyno?
Thanks, Mike
"

[madmatt]

About anywhere in Indiana. How far from Indy are you? Man we're absoulty covered up. Taking appts. a week and a half in advance. The word now is to replace'em all if putting fuel in the oil. Only supposed to do'em one at a time if missing.

[MIKE MOG]

Hi Matt,
IM about 5hrs from indy, Who do ya know with one? I will keep an eye on the fuel in the oil. The tech said he could not get this thing to miss but he said that I had #2 injector overfueling. he replaced it and things are great at this time, but I worry the rest will go when IM on a trip or something of importance. We just use this truck to pull the camper and when I need a truck, Its not a daily driver. Anything I should watch for?
Thank's Matt!
Mike

[madmatt]

I'll be in Terre Haute the 26-28 for Schied's Diesel extravaganza where they will have two dynos, a Mustang and a Dynojet. If it was overfueling, it would cause a miss like condition known as a fuel knock. Did he say how he knew it was overfueling?

[MIKE MOG]

No Matt, He did not. I would bet he used the tech 2 to check the injectors. After the repair the Mis is gone but the vib is stll there. I cant make it the 26th to the 28th but I may be in your neck of the woods in late Aug. I will let ya know.
Mike