I have a 97 3500 cummins completely stock with about 165000 miles. For a few months, when under a load the truck will suddenly lose power and blow both white and black smoke mostly white. It will not die but the only way to get it to take off again is to step on the clutch, let the engine drop to a idle and let out on the clutch it will then take off until it does it again. Some interesting things about the problem is that it you cannot make it do it when the weather is cold (say under 40 degrees F) also, after it does it once it seems to do it easier from then until it cools completely. Obviously I have changed the fuel filter repeatedly I have tried injector cleaners and fuel conditioner but nothing has helped. Fuel line issues have been suggested, as well as lift pump and injection pump problems. The problem is that I have talked to several dealers and all seem to go for the most expensive problem to start with, the IP. That may very well be the problem but there is just something disturbing about being told it is a $2800 problem without even seeing the truck.

Also, if it is the IP is there any way to lay your hands on the protocol for removal and installation of the pump, as I will most likely have the pump rebuilt at a reputable local shop.

Thanks for all of the info.
G.D.

 

I had the same problem and replacing the overflow valve corrected it. My theory is that as the fuel becomes hotter a weak spring in the OF valve loses it's springiness causing fuel pressure to drop.

You won't find a better price on a OF valve than here
Precision Diesel Injection and Turbo Inc.
Marty Tompkins
888-734-7349
$35 + $7 shipping and handling.

Replacing the OF valve is a five minute one wrench job if you don't drop the sealing washers, stuff a rag under the valve to catch a falling washer. Remove the old valve and put new one in it's place. Occasionally the notch in the manifold you see to the left of the OF valve in the picture needs to be filed or ground a little to allow the old valve to be removed. Don't bend the line to remove the valve, it will make it very difficult to line up right again. New style OF valves don't always have the retainer on top that says not to remove, don't worry it's just a design change.

The object in the lower left corner is the oil fill cap.