Engine/Transmission (1994 - 1998) truck dead on road again

[Nate Skate]

What could be wrong? Runs like its out of fuel and then dies. Has plenty of fuel though. tried to manual pump primer and never could get pressure, usually when I push the primer I begin to hear fuel squirting and I cant now. But later it started and ran great for several days. When I stopped and didnt drive it for a couple of days it started great, instantly. Then driving it tonight it seemed to run out of fuel again. Couldnt prime fuel up. BTW put a new lift pump on it trying to solve problem. Didnt work much better. Could it be the overflow valve sticking open. How can you tell if it is broke? Thanx for help

Nate

 

[Nate Skate]

Does anyone know the part no. for the overflow valve? and how do you change it? I changed the return line about a year ago. So I think it might be the overflow valve.

Nate

 

[Deezul1]

The overflow valve is located in the Banjo bolt on the return line at the front of the pump closest to the engine. There is what looks like a small bolt attached to the top of the banjo bolt and the overflow valve is under that small bolt. The best bet is to remove the Banjo bolt and then remove the valve from it. Put a rag under the banjo bolt to catch the sealing washers when they fall out (2 pieces). Measure the spring and if it is shorter than . 500 then stretch it to . 550. The length prolly is not the problem as usually that causes low power problems. You might find a broken spring though. There is only a spring and a check ball in there and maybe some shims. If the bolt hits the manifold and wont come out then file the existing notch just a little more for clearance.

Good Luck

 

[Nate Skate]

if the spring is not broken does this mean that the overflow valve is ok? Not sticking open?

nate

 

[Andy Redmond]

Just because the spring is not broken doesn' t mean the ov. flow valve can't stick open, closed etc.



Cummins 3932096; Mopar 4883838AA; Bosch 2417413093, not 086.



When you try to prime the lp, and you get "nothing" bump the engine over to try it on a different spot on the cam.



You should get some resistance if its pumping fuel.



Have you ck'd to see if the fuel shutoff solenoid or solenoid relay are killing the fuel to the pump?



Is the sending unit in the tank of known good health, are you sucking air? You referenced the lift pump not "doing anything", so does it have a fuel supply?



Good luck

Andy

 

[Nate Skate]

took out the overflow valve and when pumping the primer, fuel came out. Put the valve back together and truck ran home but ran rough. Starts rough. Could be the sending unit in tank. Know that before I bought the truck some idiot tried jacking up the truck by putting the jack under the tank. How much is one of those sending units? anyone know?

Nate

 

[Nate Skate]

How do I check the solenoid , I found the relay easy enough but dont know where the solenoid is. Also just checked cummins in louisville they want $91. 00 for a new overflow valve , seems high is this normal

nate

 

[redram]

If it's the "sending unit" then fill the truck up with diesel and it doesn't matter what the "fuel sending unit" is doing.



If someone pushed (jacked) up the tank bottom, you may have bent the fuel pickup line, un-related to the fuel sending unit which is a rheostat float mounted on the side of the fuel module (which is the 6 inch round plastic module that gets inserted into the top of the fuel tank.



You '96 does not have a fuel pump in the fuel tank, just a fuel line pickup unless it has been modified.



If you have to replace the sending unit, it's fairly cheap at about 25. If you have to replace the fuel module, it's 200+ from the dealer.

 

[rnolen]

overflow valve

call piers or andy redmond for a overflow valve. i picked one up from piers and is only cost 55 bucks.

hope this helps

russ

 

[Andy Redmond]

Nate:



When its running rough go under the hood and lift up on the arm attached to the solenoid. It should be within 3/16" of being all the way up/retracted. If you can lift it up more than 3/16" or so, the pull coil isn't holding it up or "retracted. "



You can also bump the starter and leave the key on afterward. This should also retract the solenoid and its a bit safer, no danger of getting into a tango with the fan.



The relay on the firewall could be worn out (two relays mounted above the fuel filter canister/filter head). Get the part from Dodge less than $60 or source a 70amp ($15-20)relay. The contacts get worn. . If the relay is shot, usually its a no crank in the am.



If the solenoid is bad the coil gets weak and won't allow it to fully retract. It can also be wiring probs from the battery to the solenoid (voltage drop). It can also be worn starter contacts etc.



Do you have any fuel psi readings?



The tank module may be suspect (you are getting aerated (sp) fuel, causing the rough running). You might also have air leaks or fuel line restriction in the supply and return lines.



If you don't have a Factory Service manual, go to the dealer and beg to photocopy some pages on how to test for fuel psi, fuel line restriction etc. .



Keep trouble shooting, you'll find the prob.



Good luck

Andy

 

[Nate Skate]

Thanx for the help. Where exactly is the solenoid found though? I want to check it next and then possibly purchase a new overflow valve. The truck would not run at all until I took the ovflow valve apart and then it got me home but ran rough.

Nate

 

[Deezul1]

The solenoid is round can lookin thing right beside the AFC housing on the pump. Its about 2" dia and 2" high and there is a shaft coming out the bottom to a arm.