NEPADennis

Gentlemen,
I have a 1996 2500 w Cummins 460,000 mi. This past year the truck required a new Holset Turbo (OEM) Front crank seal, belt tensioner, fan clutch, water pump, radiator. The original turbo wasn't putting out anything. The New turbo works fine. I have a 4 hour
drive from NEPA to NoVA for work. after about 2.5- 3hrs with the cruise on 70 I start loosing power on hills. Now I'm feeling the power loss after about 65 min of driving. I feel the throttle with my foot go to the floor and the speed just decreases and the tail pipe spews white smoke. When I go through the gears ( 5 sp manual) after its been driven a few hours, I take the gears up to 2000 RPM and I get a puff of white smoke and the truck falls flat on its face. The boost dies. The truck just... BLAH The Boost gauge goes up to 20# and will stay there while I'm accelerating, when the engine is cold.
When the engine has run a few hours it goes as high as it can until I hit 2000 RPM then the boost dies. Looking over the threads I have ordered a set of intercooler boots. They should arrive by the end of the week when I get home. I have no after market filters or performance
upgrades on the truck. I can change out the fuel/water separator but this problem seems to take some time to develop. Im also thinking about a new MAP sensor. Anyone have experience like this? Could this be related to a defueling problem? The boost gause says 19-20 # max can't get more than that, and then why not defuel early why wait for 2-3 hours?

oliver foster

You posted in the 1st gen ['89-'93} section, but that is fine I have had a few 2nd gen Dodges too.

It sounds like a fueling issue for sure.
I have had similar problems [other than the waiting 2 hours to happen] when the OFV [Over Flow Valve] starts to get weak. Low power, white smoke, low boost and stumbling at higher RPMs.
Next time it happens try lightly pinching off the rubber fuel return line temporary and see if it restores power. There is a length of rubber line behind the injection pump near the fuel filter housing.
DO NOT keep the return line pinched, if it helps, as a fix.
Ordered a new OFV they are cheap.

If not I am afraid my next guess would be your injection pump is starting to die.

It is not the intercooler boots, other wise your loose boost #s would be followed by lots of black over fueled, under air flowed smoke.
I had my intercooler boot blow off my '95 towing last month. It sounded like a shotgun blast in side the truck, which then lost a lot of power. I was wondering what happened till I saw the huge cloud of black smoke the truck was dumping out.

NEPADennis

Sorry about the cross post, Thought I was in the right ballpark.
The truck had a total fuel system rebuild in 2012, Fuel pump lift pump injector pump along with fuel lines. They had to use rubber hose for the return line since they ( dodge dealership yes i paid dearly)
did not have the part, ( and would not buy it from outside dodge, I dont go there anymore)
The only after market items I installed are a boost/egt gauge and a prime lock system which relocated the fuel / water separator
to the front of the engine for ease of change.. Thanks for the information on the OFV I will certainly look into that.

oliver foster

It might be a lift pump issue, but strange that it would take hours to show up.

Try installing a fuel pressure gauge, even if it is just s temporary one after the fuel filter.

Is it a factory style cam driven lift pump not the unreliable electric style ones?

You are going to find that it will be a fuel delivery issue that is giving you this problem.

NEPADennis

yes its a factory lift pump. and a rebuilt injector pump.

oliver foster

Good as I find those fancy electric fuel lift pumps are expensive but fail often.
I replaced the one [Air Dog] on my old '01 24V 5-6 times over a little over 100,000 miles.

NEPADennis

Took the Truck to Lanning's Diesel Service in Huntingdon Mills PA. Lift pump was an after market unit that the Dodge dealer put on in 2012. And it wasn't lifting anymore. They replaced the Governor and Governor springs on the P pump, also replaced some fuel line.
The repair bill was only $400.00 Then I had him turn it up! Added a new pyrometer and TC, a new boost gauge. Since the turbo now puts out 40Lbs boost. The tuning cost $1000.00 with 400+ of that for gauges.
Now the 96 12V is running like it never did before. Put 400 miles on it on a trip with the cruise on 72 mph and still got 20 mpg. Next trip I will try at 65 !