Cummins Trouble

[Sun2bfre]

Hi All, I hope someone can help me. My 98, 24 valve cummins decided to crap out on me. It was running well and just lost rpm. It started to run really bad and won't get above 800 rpm. Anyone have any ideas on what I should check before taking it to a mechanic? Thanks for the help......Sun

 

[bfdiesel]

cummins forum will be your best bet

 

[shortbus4x4]

Check your electric lift pump, its on the left rear of the block. They like to go bad all the time and then your VP44 injection pump goes out, the lift pumps don't like the vibration or heat of the engine. The VP44 creates a suction so your engine will run but your IP will be getting starved for fuel which damages it. I have changed quite a few lift pumps and injection pumps on 24 valve Cummins. Sometimes towing or pulling a grade you will notice a lack of power with a bad lift pump. I have also had a few people come in for an oil change and fuel filter change and then the truck won't start 'til they replace the lift pump because the fuel system lost its prime when I replaced the fuel filter. If your lift pump is kaput I am willing to bet your IP is too or will be soon. Upgrade to an intank lift pump or an after market FASS pump with a fuel pressure guage or a low pressure warning light.

 

[blue dog]

Check your electric lift pump, its on the left rear of the block. They like to go bad all the time and then your VP44 injection pump goes out, the lift pumps don't like the vibration or heat of the engine. The VP44 creates a suction so your engine will run but your IP will be getting starved for fuel which damages it. I have changed quite a few lift pumps and injection pumps on 24 valve Cummins. Sometimes towing or pulling a grade you will notice a lack of power with a bad lift pump. I have also had a few people come in for an oil change and fuel filter change and then the truck won't start 'til they replace the lift pump because the fuel system lost its prime when I replaced the fuel filter. If your lift pump is kaput I am willing to bet your IP is too or will be soon. Upgrade to an intank lift pump or an after market FASS pump with a fuel pressure guage or a low pressure warning light.

/\ this. Fass or airdog etc fuel pump is a must on 24 valve. 99 out of 100 if the vp44 goes, it just goes, and the truck will not start at all. Check the fuel pressure at the vp44.
I still feel that a 24 valve with fass pump or similar unit is less likely to have failure then any 3rd gen loosing injectors. Common rail causes to much pressure for injectors to live in the long run. Cheaper to put a fass and replace a vp44 then replacing injectors on a 3rd gen.
Good luck.

 

[Rot Box]

I agree it it is likely fuel related. Aside from what has been mentioned how does it respond to you pumping the throttle petal? Sometimes those go bad and you have what is referred to as a "dead petal"... Hopefully it throws a code soon. Good luck.

Andrew

 

[blue dog]

Forgot about that.

bump the key 3 times and see if a code displays in the odometer.

 

[shortbus4x4]

APPS (accelerator pedal position sensor) being bad can make it have no throttle response but it should still run fine. Check your codes, P0216 and/or P1688 mean new VP44 time.

 

[Kaisen]

Another vote for the lift pump....notorious

 

[Sun2bfre]

Thanks for all the info. When it starts, it runs like crap and won't get over 800 rpm. Pumping the throttle doesn't do anything. I'll start following your suggestions. THANKS AGAIN. Much appreciated........Sun

 

[Rot Box]

A friend had a VP44 die and it gave those same symptoms. Never did throw a code..

 

[shortbus4x4]

A friend had a VP44 die and it gave those same symptoms. Never did throw a code..

In that case crack one of the injector lines at the head and have someone crank it while you watch, it should be spurting diesel pretty good with a good IP, no spurts or just a dribble then your IP is bad. Of course this is with a good lift pump. Another thing I have noticed on some failed lift pumps is when I pull the fuel filter there is quite a bit of metal flakes in the bottom of the bowl and on the filter.

 

[blue dog]

The only thing i can not figure out is that most of the time [99% of the time } if the vp fails, the truck will not start at all. The op said it starts and will not go over 800 rpm.

 

[Sun2bfre]

I went out and "bumped" the key three times. All I got was "ABS", no numerical code. After it died the first time, I only tried to start it about 3x's. It started, but barely. Definately sounds like a fuel problem. Thanks again all. Sun

 

[Sun2bfre]

One more thing. When I had the fiters replaced a couple of months ago, the shop had a hell of a time getting it started again. I thought I was going to have to replace the starter also! Was this a "sign" of things to come?..........Sun

 

[Sun2bfre]

One more note. When I had the filters replaced a couple of months ago, the shop had a hell of a time getting it started again. I thought I was going to have to replace the starter too! Was this a "sign" of things to come? Sun