injector pump? or lift

[2K1HO]

My 98. 5 dually is sick. I've read some posts about guys having pump failures. My symptoms are similar, loss of power, bucking, and idling like it's running on 5 cylinders. Is there a procedure I could do to find the root of the problem?

 

[DHatfield]

I would first hook up a pressure gauge after the lift pump to see if pressure is between 8-10 PSI and if it is than its not the lift pump and could very well be the injection pump I think or if also could be air traped in the fuel system so try bleeding the low and high pressure side of the fuel system.

------------------
2001 2500HD Quad Cab SLT SB 4x4, HO Cummins, 6-speed, 3. 55 gears, LSD, brightwhite/driftwood, 4w ABS, camper and trailer tow packages, HD transfer case, snow plow prep, group, cab lights, Isspro Boost and Pyrometer gauges mounted on A-pillar, 4" JRE exhaust, BD exhaust brake. 27100 miles and counting as of 1/16/01.

1980 CJ-5, Modified for off-road use, bobbed fenders, 350 TBI, NP435 trans, 4. 56 gears, Dana 300, Dana 44 front, Dana 60 reverse-cut rear axle, ARB air lockers front and rear, 15/35/15 Super Swamper TSL on 10X15 steel rims, Cobra CB, Warn 9000I winch, nerf bars, 1/4" steel rock crawler bumper front and rear, jerri can/spare tire rack, custom roll cage.

 

[2K1HO]

thanks, i don't want to sound stupid but, is the lift pump in the fuel tank like a gas engine vehicle? I'm assuming the injector pump is under the hood. One of the guys here said they got a new lift pump from Jeg's, so i figured it must be similar to a gas fuel pump. I'm new to the board and appreciate all your help.

 

[Chad Sheets]

A fuel gage hooked up and read often is your best bet. I have seen lift pumps go dead for minutes at a time, then come back to life just as strong as they were day 1, and last for several hours... then they die again for a while etc.

------------------
Always ready to help!
2000 2500 Red Sport quad cab, 4x4, K&N, DDI's, straight piped, boost, pyro and fuel pressure gages, Hot Power Edge, EZ box, mean looking set of 33. 5" tires, Snap On diamond tool box, Marine Corps window sticker, Semper Fi!

1972 340 Cuda'. Original tripple Black, 340 car w/air. Good clean car, super stock springs, Weld Prostars, shaker hood, strong 340 with a 727/4000 stahl, 4. 56... . Bombs away!
NRA Life Member
My Diesel Page

 

[Evan A. Beck]

Your problem may be caused by vacuum in the fuel tank. My 98. 5 had the infamous "cap on the rollover valve" problem, and it ended up needed a new tank. The rollover valve is locaed on the top of the fuel tank. It is white, and if yours has the cap on it, it will be a small red cap. Remove it, and you'll hear air being sucked into the tank.

Your problem may also be low fuel pressure, so get a gauge and test it both at idle, and while driving. This will give you accurate results. Check your fuel filter too, and make sure it is good.

 

[2K1HO]

the truck has been sitting for a week, I started it up and it idled perfectly for a minute or two then started missing. The longer it sat there and idled the worse it got. As far as the vacuum thing, wouldn't unscrewing the gas cap relieve any vacuum? I have noticed in the past when i was refueling that it would hiss when i loosened the cap. I'm not real familiar with diesels but i've owned this truck 3 years and 110,000 miles with No trouble what so ever.

 

[Archive]

Yes the injection pump is on the engine block. Open the hood and look on the right side of the engine (facing it) and towards the top of the engine you'll see the fuel injection pump. If you lookng towards the bottom and rear of the right side of the engine you'll see the lift pump on the enigne block as well. So people have relocated their replacement lift pumps near the fuel tank as they have pumps that push better then pull.....

 

[Evan A. Beck]

2K, the rollover valve on the tank is supposed to eliminate vacuum in the tank. If you are hearing a hiss when you take the filler cap off, then you have a problem. The tank is supposed to be self-venting through the rollover valve.

Here's a diagram to help you. The part you will want to take a look at is circled in red. IF there is a cap on the end of that part, it will be red. Remove it and see what happens.

#ad

 

[2K1HO]

thanks guys.

------------------
2001 Red quadcab 4X4 2500 H. O. 6sp.