Engine/Transmission (1994 - 1998) overflow valve

[Mhannink]

where is the best place to get an overflow valve i just got one from cummins cause my fuel pressure was a little low but now w/ the new one its even lower. im wondering where there is a good place to get the right one. im not near the cummins dealership anymore and therefore difficult to get one from there

 

[McLaughlin]

Don't know that its the best place but you could try here . However, since you've already replaced it once, I'm assuming with a new overflow valve, are you sure you don't have a lift pump issue? Also, have you replaced your fuel filter recently and made sure your prefilter is clean? Either of those can cause low fuel pressure also.

 

[bdcraig]

When checking the fuel pressure reach over and pinch the return line from the pump to the tank. This takes a little manuvering to get to . If the gauge goes up when you pinch the line then it is the over flow valve. If not, then change filter and see if that helps and if it doesn't it is likely your lift pump. Piers and TST sell the valve for less that cummins.



brian

 

[Mhannink]

well i noticed a new chariteristic when it sits for a long time think hours it wont start easily right away and when it does the fuel pressure is zero after a little high idleing it will pick up and run normal for a time. also something ive noticed is if you check it like dodge says to w/ no load its higher then spec but running down the road its a lot lower. with the old one it would basicaly stay at 20 psi crusin and drop a little under full load not i can pull it to zero and it is at about 15 crusin. but ill do the checks ya'll suggested anyways. keep the advice comin

 

[Highfinance97]

well i noticed a new chariteristic when it sits for a long time think hours it wont start easily right away and when it does the fuel pressure is zero after a little high idleing it will pick up and run normal for a time.

i just went through this on mine, the return line was cracked(thats normal on a 12valve :-laf ) so i replaced it and now i have better starts.



Its a pain to get the old line out, since i was replaceing mine i just cut it and replaced it with rubber fuel line so i didnt have to take the injection pump off







Michael

 

[Mhannink]

i just went through this on mine, the return line was cracked(thats normal on a 12valve :-laf ) so i replaced it and now i have better starts.



Its a pain to get the old line out, since i was replaceing mine i just cut it and replaced it with rubber fuel line so i didnt have to take the injection pump off







Michael

are you talking about the hard line being cracked? cause ive already replaced the rubber lines a couple of times.





on another note though i just got the truck towed home cause my fuel pressure dropped to 0 and i could not get it back up. im thinking its the lift pump now the problem happened after it had sat for a time at a basketball game when i started it run fine for a little while fuel pressure fluctuating finally it dropped to 0 and started runnin bad then it died completly i had my foot in the floor and got nothing. anyways fuel pressure dropped off and truck died. i tried priming the pump and restarting but it wouldnt happen. i checked and there is some fuel in the filter though not sure what that means. anyways is it the lift pump or something else. one thing worth mentioning is i put the tank in the other day and i noticed the line that is in the tank w/ the little plastic delimobober thingy(yeah thats the technicaly term) had a little bit of a pinch in it. it didnt look bad to me but who knows could be restricting it enough. thats just a thought.

 

[biggy238]

Given the original post was about a 95 (I thought) You might take a look at the supply and return lines where they come down from the top of the fuel tank next to the frame. Mine (a 96 model built in 95) has worn through the return line and was partly through the supply line. The truck was sucking air into the return, down into the fuel pickup, and right back into the fuel system, giving a low fuel pressure. I put some epoxy on the lines and split rubber hose and put around as shiething. I couldn't ever really see fuel dripping down over the tank from outside with the bed on. When we pulled the bed, and wiped the line down, it started shooting a jet of fuel out with ever lift pump pulse.



If you go through all of the other fixes, It might be worth looking into.

 

[Highfinance97]

are you talking about the hard line being cracked? cause ive already replaced the rubber lines a couple of times.

Yes the hard line from the overflow valve to the rubber return lines.

Its know for cracking





Michael

 

[BigPapa]

my fuel pressure dropped to 0 and i could not get it back up.

You might want to check your pressure before the fuel filter and/or replace your fuel filter. I have had a filter clogged up with sludge, my opinion from the change over to ULSD. My lift pump started tapping loudly and my pressure dropped. Pulled the filter and it was full of black gunk.



Scott

 

[The patriot]

Yes the hard line from the overflow valve to the rubber return lines.

Its know for cracking





Michael

Mine was cracked. I have a 1998 12 valve.

 

[Jim Fulmer]

That line is a piece of junk as is the factory supply line.



Jim

 

[McLaughlin]

well i noticed a new chariteristic when it sits for a long time think hours it wont start easily right away and when it does the fuel pressure is zero after a little high idleing it will pick up and run normal for a time. also something ive noticed is if you check it like dodge says to w/ no load its higher then spec but running down the road its a lot lower. with the old one it would basicaly stay at 20 psi crusin and drop a little under full load not i can pull it to zero and it is at about 15 crusin. but ill do the checks ya'll suggested anyways. keep the advice comin

The lift pumps have a reputation for reliability; however, they can fail in a couple of different ways. One thing the pumps have are some check-valves (three I think) which maintain fuel in the lines when the truck is turned off. If the check valves fail you may have trouble starting the truck since no fuel is available. One inexpensive thing you can do as a check is to manually prime the pump (there is a push button on the pump) and see if it starts right off that is an indication you are loosing prime either due to an air leak or a bad check valve. Another thing to check on the lift pump is take a close look at the prime button area on the lift pump, sometimes the pump will develop a leak there and you will see fuel on the button. Upside is that if that is the only leak you can sometimes replace an o-ring as an inexpensive fix.

 

[Mhannink]

well my buddy has a spare lift pump that im gonna put on and see if thats the problem. i know the reputation for these pumps so im wanting to check into all avenues. as for the hard line im pretty sure its not cracked we checked over all of them and there are no vivible leaks anywhere in the whole system i did look at the rubber lines above the tank when i was putting the tank back in and they looked all right though i could have damaged them when putting the tank in.



i havent yet done any of these checks simply for lack of time but the first thing im starting w/ is a more intensive look at the fuel lines return and supply as well as replacing the fuel filter since i know its about time to be changed and w/ the new fuel could clog it real good. i still wanna here all the checks that may not have been mentioned yet and thanks all for your advice keep it coming please.

 

[The patriot]

I wouldnt go through all that unless it was a NEW pump.

 

[Cooker]

i tried priming the pump and restarting but it wouldnt happen.

After reading this I would start with the lift pump.



Open the bleed screw on top of the fuel filter and push the primer button on the lift pump. If you are getting nothing out of the bleed screw, your lift pump failed, assuming your FF is not plugged up.

 

[Mhannink]

I wouldnt go through all that unless it was a NEW pump.

my understanding is this is a new pump he was gonna put the 12v lift pump on his 24v but then other things happened and he decided not to so now he has a p3000 injector pump and a lift pump.



cooker i think tomorrow i will be changing my fuel filter then priming it like you suggest and see what happens and go from there

 

[Mhannink]

well i pulled the old lp off and found a bad one way valve. the one that leads into the pump from the tank actually. so im putting the new lp on now. its a good thing these things dont burn up often cause they are a real ***** to replace. i spent all day getting this one in and i still need to hook up the fuel lines. anyways thanks all for the help ill let ya'll know what happens when i get the truck on the road again.

 

[Signal73]

pulling the starter (3 bolts) makes it much easier. Also good time to do the starter contacts if you havent done them already.

 

[WDixon27]

mine took a couple hours maybe less it's been a while, pain in the butt but didn't seem like a all day job

 

[TSPowell]

Does anyone know where to get the steel fuel line from the overflow valve that decently priced. Im assuming from Cummins..... Part #???