Engine/Transmission (1994 - 1998) '97 new lift pump, now it won't run?

[BMorgan]

Hello to all on the TDR. As you've probably noticed this is my very first post so I'm hoping not to mess it up too badly.



The lift pump on my '97 was leaking at the bottomside of the plunger so it's time to change it out ( the truck has 86,000 miles). To access the pump I removed the fuel filter cannister (installed new filter). Installing the new pump went fairly well once I realized life would be easier if I release tension on the lines (at the top of the cannister housing) that extend to the pump and pre-heater.



Before starting the truck I gave the plunger 20 or so pumps. No luck, the truck would not start. I pulled the cannister off and filled it with fuel since there was little in it. I thought pumping the plunger would have filled the cannister since that seems to have worked in the past. I eventually was successful in starting it but oh did it smoke and run rough. It ran for about a minute then stalled. I cranked it over for a while and it would not restart. I depressed the plunger a bunch of times again and still nothing. The cannister came off again and sure enough it was low. I filled it up and eventually the truck started . Again there was lots of smoke and the truck ran very rough, however it did smooth out some but not completely. This time it ran for about two minutes then stalled. I cranked it over a number of times but no luck, it won't start.



This may help so I figured I would add that the truck is completely stock and I have replaced the 5/16" fuel (return?) line. Any help would be greatly apprecited. TIA.

 

[The patriot]

Welcome!!

There's a bleed valve on top of the cannister on my 98. I sometimes have to open it to fully purge the air out of the system.

Sounds like this is it.

Eric

 

[BMorgan]

Hi Eric. Thanks for the quick response. I should have mentioned that I did open what I think is the bleed valve. Is it the 10mm bolt atop the cannister housing toward the front of the housing? I hope that is it. There is also a doble banjo type fitting toward the rear or firewall side of the cannister, could this fitting possibly be the bleeder and I'm missing it? Thanks again.

 

[The patriot]

If you get only fuel from the bleed plug,(NO BUBBLES!) try cracking the injector lines loose and cranking the engine.

When it starts, shut it down and retighten the injector lines.

Eric

 

[24VChev]

lift pump

What brand pump did you install. I have found that the Delphi pump can have a shorter push rod attached to it. Therefore it will not pump fuel properly. I have also had them bad right out of the box. It should only take a few dozen pumps to get fuel. Try removing your filler cap from the fuel tank incase there may be a vacuum.







Malcolm

 

[BMorgan]

Eric, I'll try the bleeder valve again maybe there is still some air in the system. I'll also give the injector line bleeding method a try.



Malcolm, the pump is a Cummins part which I believe is made by Carter. I didn't try pumping the plunger with the fuel cap off, I'll give that a try.



Thanks guys, I'll keep you posted.

 

[BMorgan]

Well, I've tried pumping the plunger on the lift pump (so many times I've lost count) and I'm not able to get straight fuel at the bleed valve. I've tried with the fuel tank cap off per Malcolm's suggestion and I still get air bubbles at the bleed valve with very little fuel. Could the new lift pump be defective or am I getting air from another source? Any further guidance will be greatly appreciated. Thanks.

 

[HoleshotHolset]

Check the fuel lines from the input of the p-pump (right beside the shutdown solenoid) all the way back to the tank.



I ran into the same situation when I did my lift pump.



After replacing the feed/return lines right by the lift pump (the stainless steel feed line was leaking a TINY bit) it has been fine ever since.



Matt

 

[BMorgan]

Another day of working on the truck and it still won't run. I've looked at all the fuel lines and they seem to be ok. After doing a search I read that purging air out can be done by inserting an air supply into the filler neck of the fuel tank while the bleed valve is open essentially accomplishing the same thing as pumping the lift pump hundreds of times (which I've done by now). Guess what it worked, finally straight fuel to the bleed valve. Excitedly I try to start the truck but nothing. I crack the nuts at the injectors figuring the air must be at this point in the system. I crank the truck over for a while and nothing. I decided to recheck the bleed valve at the filter and sure enough air bubbles again, no more straight fuel. So, back to pumping the plunger in hopes to get straight fuel. That didn't work. All I get is air bubbles.



I'm starting to wonder if the new lift pump is defective and if it is will it exhibit the symptoms that I'm experiencing? This is starting to get a little frustrating, especially since a leaking lift pump (the initial problem) seemed as though it would be a simple fix. Sorry for the venting, I'm a little bummed because my truck has been down for 4 days now. Any guidance would be greatly appreciated. Thanks

 

[24VChev]

lift pump

Sounds like the lift pump is toast. You did not loose the pushrod did you?





Malcolm

 

[BMorgan]

Malcolm, I don't believe I lost the pushrod. I say this because it required some inward pressure on the pump to get the two bolts started. I guess the only way to tell is to pull the pump back off? Assuming that the pushrod is intact does a new lift pump that is defective not allow one to bleed the air out at the bleed valve? And, would a defective pump tend to pump air into the system? I apologize if the answers to these questions are obvious. This is my first diesel so I'm learning as I go. Thanks.



BTW, is it common for a new lift pump to be defective or did I overlook something during installation?

 

[illflem]

You're sucking air somewhere, it could very well be the new pump but I sort of doubt it. I'm leaning more towards the line from the fuel heater to the pump or the fuel heater itself. The problem is somewhere on the suction side of the pump. Pressurizing the tank like you did to bleed while another person sprays soapy water over the lines may help find the problem.

Sorry, have to ask, how much fuel is in the tank?

 

[BMorgan]

Illflem, unfortunately the fuel gauge doesn't work and I'm not sure how much fuel I lost when I drove home (about 20 miles) with the old lift pump leaking. I do know it was leaking at a pretty good rate because the underside of the truck was very wet and the were a couple of cars behind me that put on their windshield wipers.



If you recall I was eventually able to get the truck running after the new pump install (albiet with lots of smoke and very rough) but it died after running for about a minute. My initial thought was that maybe it was low on fuel so I added 5 gallons. Based on the mileage on my tripometer I should have had at least 15 gallons in the tank before adding the 5 gallons. However, I'm not sure how much I lost driving with the leaking pump. Assuming I lost alot or close to all of it do you think the 5 gallons I put in is insufficient?



Should I pull the lift pump back off or is there a way to test it without the truck being able to run? Thanks for the help. I'm looking foward to resolving this issue since the truck is my daily driver and I also use it for work.

 

[The patriot]

I'd pressurize the tank again (low pressure) and start looking for a leak.

Eric

 

[illflem]

It has to be a leak. Do what Eric says, 10 psi max. The injection pump will suck fuel from the tank even if the lift pump is doing absolutely nothing as long as it is primed and the truck should keep running. Just a little shot of air will cause you to lose prime and stall though.



5 gallons should be enough, but another question- do you normally run your tank down till it requires a 30 gallon fill up? The thing that is puzzling me about your problem is that it coincided with the lift pump replacement. Holes in the tank module pickup tube aren't that uncommon but won't show any symptoms till the fuel level is below the hole. You might not have reached the level of a hole before and it never showed itself.

 

[RBrunson]

Fuel return line

You said you replaced the 5/16" fuel return line. I had problem similuar to yours becouse I reused the stock hose clamp on the fuel return line. It was good and tight but it still let air into the system. Just another item for you to check.

 

[Tardog]

BMorgan



If you are still looking for Ideas, try taking off the suction line to the lift pump and put on a temp piece of hose and put it in a can of diesel. Then try priming and starting. this will determine if the lift pump works or not with out taking it off the engine? Good luck

 

[BMorgan]

After pressurizing the system with low air pressure (through the fuel filler neck on the fuel tank) a leak was revealed. Initially air came out and then there was a good stream of fuel flowing from the plug recepticle on the pre-heater element. I wasn't sure if it was leaking from the gasket above so I unplug the wires to the element and pressurized the system again. Sure enough the leak is coming from within the oval shape recepticle that excepts the element wiring harness. After removing the element I confirmed it was leaking there by standing the element upright and filling the plug recepticle with fuel (which leaked right out).



There is a gasket on the top and bottom of the element but I'm not sure what seals the area around the two prongs? It looks as though they are set within a plastic of some type however I don't see any type of o-ring or seal.



I'm in the process of trying to find a replacement element through Cummins however I'm not having much luck yet. I was able to locate the entire pre-heater through the dealer (2 days and very pricey). I was hoping to replace just the element for both price reasons and ease of installation (trying to avoid pulling the lift pump off again).



Thanks for all the responses and I'll keep you posted as to whether this solves my no run problem. I'm a little concerned that this leak didn't show itself yesterday when I pressurized the system. Maybe it's because I had the bleed vavle open at the fuel filter? Anyway, thanks again for the guidance.

 

[illflem]

All the heater parts are available separately, sorry I don't have any numbers.

In the meantime you can bypass the heater till winter or if you live in a warmer part of the country forever.

 

[BMorgan]

Illflem- How do I go about bypassing the heater? I'm all for that since I can't seem to locate the element or any related parts seperately. The local Cummins dealer seems to be having trouble locating anything related to a pre-heater. He's not even sure that the truck came with such a part on it (seems odd)? He did say that they have a strainer in conjunction with the lift pump but not a heater/pre-heater. So I don't know. Like I said in a previous post the dealer had no problem coming up with the part, however you have to buy the entire pre-heater at a price of over $250. 00 with a 2 day leadtime. At this point if I can get the truck back on the road by bypassing the heater, that would be great (gives me time to locate the individual parts). Thanks for the help.