Engine/Transmission (1994 - 1998) fuel problem.....please help!!

[AMcKee]

hey guys,



im new to the turbo diesel scene so bear with me. i just bought a 1997 3500 4x4 5 speed with 146, 000 on the clock. as i was driving home the truck began to lose power. i could apply more throttle and there would be no response. the truck would slow down to like 35-40 mph for about 30 seconds then speed back up for another 30 sec. and so forth. when i pulled off the road the truck would stall. about the 3rd time it stalled it would nt start up. i had it towed to a guy who was a dodge tech for the last 17 yrs. at first he thougt the injector pump was bad, he later noticed the fuel shutoff solenoid was in the down position. he manually lifted it and the truck started up. he rigged it up so i could limp the truck 9 hrs home. so basically the truck would speed up and slow down the entire trip and occasonally stall if i let it idle.



im concearned that something is wrong with the injector pump like maybe it cant keep pressure up on long distance drives. has anyone experienced this problem or have any suggestions?



i ordered the shutoff solenoid and have not yet changed it. the solenoid is definately malfunctioning but im just concearned that replacing it will not remedy the problem.



thanks for the help,

andy mckee

 

[bighammer]

Check for leaks behind the engine (rubber hoses)



Check and/or replace overflow valve



Lift pump output may be low, or fuel filter clogged? Or maybe fuel strainer in tank or the screen at the heater?



All I can think of at the moment

 

[Andy Redmond]

The shut down solenoid relay (firewall above fuel filter, the big one) may be the culprit rather than the solenoid. Search the archives for "JOEG" he's posted the sequence for ck'ing it.



The performance issues you describe (provided the solenoid is wired up) seem to be a fuel supply or aeriation (sp) issue it would seem.



Next time it stalls, run out under the hood and find the fuel transfer lift pump (under fuel filter/above starter on drivers side of engine block), look for a black rubber cap that has 'bellows" attached, its a manual primer. Push it about 10-20 times, if it fires right up, you may have some check valve issues in the transfer pump or the overflow valve may stick open sometimes. Ov. Flow valve is a "banjo bolt" that attaches the steel return line to the intake manifold side of the injection pump where it mounts to the gear housing.



Better yet find someone with a fuel psi gauge to ck. for fuel psi. s/b at least 20 after the filter at rated rpm. I like to see 20 at idle and close to 30 psi off idle.



Big Hammer gave other suggestions that I would ck. as well.



Finally it may be a pump/gov. issue, but troubleshoot and rule out the more inexpensive repairs first.



Good luck and let us know what your fix is.



Andy

 

[nfox]

Surging

I would suggest checking the fuel pressure also, i would replace the prefilter screen on the fuel heater and the fuel filter. Start with the simplest and cheapest things first. Let us know what you figure out.

 

[JAmos]

I second the suggestion of checking the fuel shut off solenoid relay. My Dads truck had problems pulling up the solenoid so we put one on and it didn't help. I searched on here which I should have done first and learned that the relay can be cleaned. I took it off and sprayed electronic cleaner in it and shook it out a couple times and it has worked flawlessly since winter.

 

[Joe G.]

Very carefully check the throttle linkage. Have someone help or use a stick against the seat to push the pedal to the floor. Then check to see that the lever is against the stop. Check for anything loose. There are two little screws that fasten the throttle linkage lever to the pump lever. They may be loose or one of them has fallen out. I had one of mine fall out and it acted something like that. The throttle linkage lever moved buy the pump lever didn't always go along with it.



An air leak before the lift pump could cause those symptoms. The fuel hose could be leaking (most likely suspect). The fitting where the steel line fastens to the fuel heater/pre-filter assembly could be loose or damaged. The electrical connector in the fuel heater may be cracked. The hose between the fuel heater and lift pump may be leaking. Before replaceing the lift pump check the lift pump and fuel heater assembly in a bucket of water with some air to see if anything is leaking air. The lift pump is a sturdy gadget and seldom fails.

 

[AMcKee]

wow guys, i appreciate the prompt and knowledgeable advise. i understand 75% of what you guys are suggesting and i will try them. i have installed the new solenoid and i also found a male and female connector that was unplugged. i plugged, whatever it was, back together. the truck starts and runs great. i havent had a chance to take it on a long drive to see if it is gonna mess up again. i will keep you posted and thanks again for the info



thanks,

andy mckee



p. s. what is BHAF?

 

[nfox]

Surging

Big Honkin Air Filter. Oo.

 

[Joe G.]

Andy,



Where was the connector? If it is in the side of the fuel heater you may have an air leak in that connector. The plug may be reducing the effect of the leak. You might unplug the connector and see if it still runs good to verify that the problem is really fixed.

 

[Joseph Donnelly]

If the fuel shutdown solenoid does not pull the pump lever all the way up, horsepower will be low.

 

[AMcKee]

Thanks again for the additional info guys. Joe i will disconnect the fitting and see what happens. Joseph i agree with you, that was intial train of thought, when i replaced the solenoid the old one almost disintegrated in my hands so i hope thats it.



thanks

andy mckee