My LB7 Injector story

[DetroitBob]

June 18, while hooking up my 5th wheel in Portland RV park, I noticed light smoke from exhaust on my 2002 GMC 3500. Thought that was unusual, but continued to CG at Sunriver.
Returned on 20 June and on 21 June prepared to leave for 2500 mile trip home to Alaska. 22 June, after TDP search, decided to have engine checked. 23 June called DSU-Peterbilt/GMC in Portland. Checked, all injectors out of limits. Replaced all 8 units. 58898 miles on truck. Great group of service personnel. All is well now.

DB

[Mark Rinker]

I hate to ask, but were they covered under GM warranty? Its unusual to see even the LB7 injectors go so soon.

Any crankcase oil dillution? Fuel knock? Other driveability issues?

[NutNbutGMC]

I hate to ask, but were they covered under GM warranty? Its unusual to see even the LB7 injectors go so soon.

Any crankcase oil dillution? Fuel knock? Other driveability issues?
My very first (of 4 sets) went at 48k.

[Mark Rinker]

My very first (of 4 sets) went at 48k.

Wow. Just wow. Had to be fuel quality related. Did you fill up randomly, or have a favorite fueling location?

[NutNbutGMC]

Wow. Just wow. Had to be fuel quality related. Did you fill up randomly, or have a favorite fueling location?
Same places within a 525 mile routine trip.

I tell ya' the first time was a surprise, as I never expected it. I have been here for a lot of years, and back in 2001 / 2002, the issue was not widely known, so there was little exchange of information.

Talk back in those days was the (improper) cutting of the cross-member of the frame in order to get the 2-piece driveshaft replaced. That too was a fiasco...

[Mark Rinker]

Sure would be interesting to see the insides of the tanks you were regularly filling out of.

My guess is one had a SERIOUS rust problem.

[dually2002]

Wondering if the higher content of sulphur in the fuel back when the lb7 was introduced with state of the art injectors could have caused problems?

[DmaxMaverick]

Wondering if the higher content of sulphur in the fuel back when the lb7 was introduced with state of the art injectors could have caused problems?

I suspect the opposite. Sulfur was never the issue (to everyone but the EPA). It's the process of removing the sulfur that degrades the fuel quality. The earliest injector problems were related to the quality/ability of the materials used in the injectors (ball seat erosion, body cracks). Decreasing the lubricity of the fuel (by removing sulfur) may have an effect on all the injector series.

[DetroitBob]

I purchased the truck in Guthrie, OK in May 2002. Only one I could find with options and 2wd. Drove from OK to KS,CO,WY,ID,OR,WA,Canada to AK. Back out in Aug 02 to OR,NV,AZ,TX,MS. Stored for 6mos. June 03 on to VA, DC, TN, GA, AL, MS, back to NW and AK. May 07 back out to NW & Return. Aug 09 back out to NW, stored for 6 mos. Picked up and repeated Aug 02/03 trip. Fueled at Flying J, Loves, Chevron, Shell, Exxon, BP, Murphy (Wal-mart), Fred Meyer, Texaco and others. Usually where it appeared there was a lot of diesel traffic. Only problem items concerned an out of round new spare and an over filled differential fluid change resulting in a leak at level plug and the usual non-shifting transmission after sitting for a week or so. Usually jack up rear wheels off ground and run thru gears ok. I do not drive the truck from about early Oct to mid May. It sits in the garage. I do start it regularly.
Never had any driveability problems. No power problems. Only thing was the bluish smoke from exhaust.
When I started the trip in Aug 09, the truck only had 39900 miles. Now it has 61800
The DSU-Peterbilt/GMC service personnel informed me that fuel was entering the crankcase because of the injectors. Oil level checks did not indicate an over filled condition. However I will admit I may not have observed closely enough. Although on my way to Portland, coming out of Denver into Cheyenne and heading west, the headwind was very strong and I could only manage 55 mph and maintain OD, for quite some time. It was either let it upshift or stay in 4th at about 3000-3200 for the same speed. This would cause the trans temps to creep up about 10-15*
This repair was not covered under 200,000/7yr warrantee as it was up May 2009.
Total cost including 2 thermostats, 2 batteries and all filters and 4 gals Chevron Delo was $4118.

I can't say enough about the service personnel at DSU-Peterbilt/GMC.

[Mark Rinker]

Thanks for the thorough description. Sorry to hear of your injectors going so soon.

A couple more questions...not meant to condemn, but to possibly shed light on why these failures can occur so early;


How many fuel filter changes in that timeframe?
Any fuel additives run?Hope your next set is your last set.

[DetroitBob]

Mark, looking at my records, here are the fuel filter service intervals:

6236
16839
21171
29362
45756
58190
58898 (with injector chg)
no additives

The new injectors p/n 97729095.

I'm guessing around 50-60% of this mileage is towing a 9000 lb trailer.

I'm not sure there is a cause/affect to filter change intervals and injector failure. A service person at DSU told me of a 02 DMAX with around 500,000 and still running the original injectors and no problems. Maybe the long running times help stem problems. My guess.


DB