Cummins Troubleshooting Help???

Need some help diagnosing a problem on my '98 3500 with Cummins 24 Valve/Auto/3.54 rears.

I just made a three day trip from Virginia to Massachusetts and back.

The trip up was outstanding - 20 mpg at 65 mph.

The trip back was somewhat less fun.

During all of the following, all dash indications (oil, temp, etc) were normal. The water in fuel light never came on. Oil and water levels are good, no discoloration in either of them after 550 miles.

I fueled up at a Pilot truck stop at exit 1 on I-84 in Massachusetts for the trip back.

About 30 miles later, the truck was "missing" if I tried to accelerate above about 70 mph and while cruising on some of the hills in north central Connecticut. The transmission couldn't figure out where it need to be when this happened. (if it were a V-8 gasser, I'd guess it was not firing on about three cylinders but this is a Cummins.)

After 150 miles, I stopped to eat and when I pulled back on the freeway, I had heavy white smoke under acceleration until I got up to speed, missing above 2000 rpm and the same "confused" transmission.

Cruise at 65 mph (1800 rpm) was normal.

After about 350 miles, the problems with the smoke disappeared, but I still have the missing at above 2500 rpm. And if I drop down out of overdrive and punch it, it is worse.

Right now, the truck appears to be running normal with good power and acceleration until it hits 2500 rpm in any gear.

No codes on the dash - Does the Cummins use the "Check Engine" light??

I'm hoping I just got a load of bad fuel and I'll change the fuel filter tomorrow and see if the problems go away.

That would explain the missing at high rpm - fuel starvation.

But what would have caused the white smoke???

I'd appreciate any comments before I take it to the dealer.

Greg '98 3500 QC 4x2 Cummins ISB, Auto, 3.54:1, Driftwood with Leather and all the heavy duty options. '89 Nu-Wa Champagne Edition, 34 foot Fifth Wheel.

Reply to
Greg Surratt
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lift pump??

Reply to
the guy

The first thing I would have done was stop and drain some fuel out of the filter and watch for moisture, then I would change out the filter element with the spare I always carry. If that didn't fix it, then I would suspect the lift pump. Install a supply FP gauge on the outlet from fuel filter. Lift pump is easy to change, you can do it from the top if you have long arms. I did mine from the bottom, takes a little longer cause you have to remove the starter first.

Reply to
Joseph Myers

Bought a load of fresh fuel this morning from a station where I've been fueling for the last three years. There was about 1/4 tank of the bad stuff left.

Changed the fuel filter. Truck is now running like a champ! Shift points are back up to 3100 rpm under heavy acceleration without missing a beat.

Couple of heartstopping moments during the filter change though.

When I took the canister off, the old filter top section stayed on the truck. I looked at what I had in my hand (just the round filter section without the top flange section) and thought to myself "Crap! They sold me the wrong filter." Got that straightened out when I started looking for the large gasket from the old filter.

Then I didn't run the lift pump by cycling the key enough times to re-prime the system. Had to crank about 25 seconds before it started.

So thanks for the comments, guys. Pays to replace the cheap parts first.

FWIW, I also carry a spare filter, but I figured I'd run the truck a while to get rid of the bad fuel before I changed the filter. Otherwise, I'd be changing it again after a tank. Just glad I wasn't dragging the fiver this trip.

Greg '98 3500 QC 4x2 Cummins ISB, Auto, 3.54:1, Driftwood with Leather and all the heavy duty options. '89 Nu-Wa Champagne Edition, 34 foot Fifth Wheel.

Reply to
Greg Surratt

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