Possible Failed Duramax Fuel Injector

I am pretty sure I have a bad duramax fuel injector on my 2001 (LB7?).  The fuel injector seems to be on the righthand bank when facing the engine (driver side). Is there a method to determine which fuel injector it is? These are replacement Duramax injectors under GM warranty, so I assume they are rebuilds, not new. Total miles: 178,000.


Duramax 2500HD Surges at Idle Only When Truck is Cold

I have a 2001 2500HD Duramax. I was wondering what would be wrong if the truck surges at an idle only when the engine is cold. It usually will not surge if the outside temp is above 70 degrees. Anything colder than 70 degrees it surges a couple hundred rpms very aggressively and the check engine light will come on. The code is low fuel pressure (P0089 I think). If I kick the RPM up to 1200 it will stop surging. My local dealer thought maybe the mass air sensor is faulty. I was wondering what is your take on it. Thanks, Kevin.


Front-to-rear bounce at 45 MPH in 2002 Duramax Diesel Shortbed

I have a 2002, short bed, quad cab that I purchased used (70,000 miles). When I reach about 45 MPH, it does a front-to-rear bounce which goes away at 50 MPH. It did this while I test drove the truck. The truck is all stock (no lift kit or anything else). I had the sales person look into it, so he sent it to a local tire store. Their answer was “worn tires and front end alignment.” So, I bought the truck. The shocks have been replaced, tires are new, front end aligned. It’s still there! I did hear a rumor that this is a problem inherent with the short bed, quad cabs. True or false? What can I do, since it is somewhat annoying especially when you have passengers. Thanks.

Diesel Chip or Program Setting DTC P0700

Why do guys running a diesel chip or programmer seem to run into diagnostic trouble code P0700? Some get it while hard driving and others under normal driving?


Duramax Diesel 2006 2500 HD Steering Column Clunk

I have an issue with the clunk in the steering column of my Duramax diesel 2006 2500 HD. I had the dealer fix it once. Apparently this is a known issue with GM as there was some kind of repair bulletin out. Question: is there an easy, better and more permanent fix for this problem? Could you show us how? Thanks, Chris F.


Poor Fuel Economy When Towing Fifth Wheel with 2001 Duramax LB7

I have a 2001 LB7 that I tow a 30 foot fifth wheel camper. I would like a little more power to pull the hills without downshifting and better mileage when empty. I get around 16 to 18 MPG. I have 130,000 miles and new warrantied injectors. The tires are 285’s. The cruise control could work a little better and really sucks when towing. I am planning to build an Air Bag rear suspension replacement for the springs. I have a gooseneck hitch and would like to be able to back under the trailer with the air bags deflated and then reinflate them to make the hitch. I am planning a panhard bar anchored to the Diff cover bolts and frame rail. The bag bracket will mount in place of the rear spring mount. The level sensor will have to come off of something yet to be found. An electric pump and a reserve tank will be mounted on the frame rail. Any suggestions would be appreciated. Thank you, Philip P.


Duramax Diesel Serpentine Belt Seizure

An issue that we just had was the seizure of one of the serpentine belt idler pulleys which of course caused the belt to break, and of course we had our 28 ft travel trailer behind us. Only 30,000 miles on our truck. I heard a slight squeaking from day 1, but always attributed it to a squeaky belt, as there are service bulletins out about squeaky belts. Turns out it would be the best $46.00 + tax (approx cost, I assume this might vary dealer to dealer) a person could spend. This is for BOTH of them. The LLY uses 2 idlers, both the same. I believe that the pulley was defective from new, and took awhile till the bearing finally seized. I will probably start changing these every other year. I kept the one old, one and a universal one that NAPA had as LLY pulleys are not a stocked item and maybe the pulleys are not LLY specific but are the same across the Duramax engines. These, along with a new serpentine belt and the tools to change them are going to always be in the truck now.

Not an issue, but it’s official. 18 MPG ! I have an 04 1/2 LLY that now has the complete 2006 airbox assembly, up to and including the turbo mouthpiece, which of course I found out about in reading the magazine article about. The best that I was able to due previously was 16.5. I have a crew cab 4x4 running 265-75-16 tires. Next year it will be an oil cooler, probably the TD-EOC. As budget and time allows, I keep making it better.

Just as an aside, I run Bilsteins and larger sway bars from Hellwig on my truck. Makes it handle like a car ! Then I have a truck cap and an accessory called a “Bed Rug”. Regards, Dave C


Joel Paynton is an award-winning GM technician who specializes in Duramax fuel systems. He also does custom programming for any GM powertrain. Visit him on the web at www.payntonperformance.com.


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