I checked around for similar issues before I posted this but my set up and problem seem unusual.


I have a GMC 6.2l with a Banks Sidewinder turbo on it. I love this truck since it gets me to the middle of nowhere easily and gets good enough mileage to get me back out. However lately...

When I start it up, it starts and runs fine. Then, after about 15-20 on the street and about 5-10 on the freeway, it starts to lose power and will eventually stall. The amount of time before this starts has decreased over time, starting at a couple of hours to where it is now. Once it has stalled, I can usually start it up once or twice but eventually, it will not start at all. I then have to wait for 20 minutes or so and, after turning over for a while, it will start with a puff of white smoke (it doesn’t do this normally).

Finding a diesel mechanic in my area is next to impossible but the one I did find hasn’t had any luck in tracking down the problem. At this point, he has checked the fuel filters, replaced the aftermarket electric fuel pump between the filters, replaced the injector pump as well as checking for air leaks.

The fuel filters were replace fairly recently as were most of the hoses.

Help! I don’t even know what direction to go in at this point.

 

Next time after you have that issue you should pour a cool bottle of water on the IP if truck runs better It is the Injector pump, and it's not said enough but run 2 stroke oil in the fuel a 1/2 to 1 ounce per gallon of fuel.

Ultra low sulfur diesel is hard on the injector pumps in a 6.2/6.5l

 

Thanks for responding.

Could that be the problem even if the Injector pump was just replaced (and it did it before and after)?

 

Didn't know about the recent IP change are you sure it was replaced? because what you are describing sounds like a failing IP, do you have the right fuel cap?

 

Well, I paid a awful lot for a new IP so I really hope it was replaced. It looks like they remove the intake and hoses and crap so, if they were trying to scam me on the part, they put a lot of work into it. I'll take a careful look at it when I get home.

The fuel cap was the first thing I thought of and I experimented with leaving it loose and off with no change.

 

Assuming the lift pump (mechanical or electrical) is operating properly, sounds more like fuel restriction, possibly a clogged fuel strainer inside the fuel tank..
Let me see if I cant provide you with GM's 6.2L Diesel Engine Student Handbook.


6.2 Liter Diesel engine 386 page PDF
No substitute for the proper FSM but far more informative if not more helpful than Haynes, Chilton and other unauthorized publications combined.
Suggest you download it to your PC, before it disappears too..

 

Thanks a lot. That handbook is a huge help.

I am thinking I will start by dropping the fuel tanks, checking them and replacing the sending units. I am currently only using one tank as the right tank needs to be replaced. It seems quite likely that the left tank might be bad as well.

 

Sounds like a clogged strainer. If the sending unit has been replaced it could have the wrong strainer in it. If it idles great with no runaways when blipping the throttle, then its prolly not the IP.

 

All set to replace the tank and sending unit and then I broke my wrist and ankle.

I am going to try to get that done this weekend with some help.

I am wondering though, does the sending unit or strainer make sense if it only happens after the truck has run for a while (10-20 minutes)?

 

Bummer about the wrist and ankle, but yeah some times them socks/strainers can be funny like that especially if there is much trash in the tank it will settle over time and when you drive it it sucks back into the strainer and the only way to solve this is to drop the tank,just loose the strainer and put a clear inline filter pre LP.