Engine/Transmission (1998.5 - 2002) Lift Pump Issue and Lots of Questions

[Eventer]

A couple of weeks ago I changed my fuel filter and after trying to start (bump the pump) the engine would not start.



I then realized that I did not hear the lift pump anymore. Thanks to a sugestion from another TDR member in the 911 forum, I pulled the plug on the lift pump and plugged it back in. I was then able to start the engine.



I just checked a few minutes ago to see if I could hear the lift pump when I switched the ignition to run (not start). I did not hear anything. Does this mean the lift pump is dead and the only reason I can start the truck is existing pressure in the lines?



know everyone will say check the fuel pressure, but I don’t have any gauges or any other way to check the pressure. That’s part of this thread.



1) How can I tell if my fuel pump is dead?



2) If the pump is dead, how do I approach the dealer and what do I tell him? I have almost 92,000 miles on the truck in 3. 75 years. The dealer I bought the truck from is 200 miles south of where I live.



3) What is a good fuel gauge? (I have AutoMeter UltraLites for boost and EGT)



4) How difficult is the lift pump installation for someone who is not all that mechanically inclined? (I believe the cost is about $150 from Cummins. )



5) What is normal pressure at idle to WOT and everything in between?



6) ... and anything else you can think to tell me.



I appreciate all your help. This is the first (potentially) major issue I have had with my truck and I want to do the truck right. Thanks in advance for all the good advice I am about to receive!

 

[Gary - K7GLD]

Well, if you haven't already, you might do the plug bit again...



The plug may have accumulated lotsa gunk that requires a thorough cleaning for a more permanent fix - the fact it worked ONCE when you messed with it sorta reinforces that suspicion. Hardware and automotive stores sell excellent cleaners for that purpose, and dialectric grease to restore a good seal against the elements.



You approach the dealer by informing him your lift pumps is dead or dying, if the above fails. No mystery on that issue - all dealers have seen it often enough...



Idle PSI will be around 15 PSI, dropping to perhaps 10 PSI with a heavy load up a steep grade. Usually, around 13-14 at cruise, empty on the freeway.



Good luck - keep us posted on how you make out...

 

[24V-DSL]

I just checked a few minutes ago to see if I could hear the lift pump when I switched the ignition to run (not start). I did not hear anything. Does this mean the lift pump is dead and the only reason I can start the truck is existing pressure in the lines?









Just checking to clarify the difference between "bumping" the starter and switching the ignition to run, not start.



If you are in a quiet setting, when you switch the ignition to "run" you usually can only hear the lift pump for a millisecond. But, if you "bump" the starter, the lift pump should run for about 30 seconds. You mention both in your post, but it was hard for me to know if you were clear on the difference of both. Apologies if I didn't understand.



EDIT: well, it's obvious I can't figure out the quote process.

 

[Eventer]

24V-DSL



Thanks for your comments. You understood just fine. I wasn't clear. I had originally just turned the ignition to run and didn't hear anything. After reading your post, I went out to the truck and bumped the starter. Still no noise.



This is not looking good.

 

[Gary - K7GLD]

Just for the record, I have NEVER heard my LP - but have plenty of pressure - just a quiet pump, or else my hearing is worse than I thought! I can hear my pusher pump briefly - it's keyed off my LP - but otherwise, nothing - and plenty of PSI...

 

[JSykes]

To provide some more input on your questions:



1. The best way to find out if your lift pump is dead or weak is to get a FP gauge.



2. While the engine is still under warranty, take it to the nearest dealer and have them look at it. The LP is a common problem and they will be familiar with it. They will probably replace it without much issue.



3. I have the Autometer Ultra-Lites in my '99 (Boost, EGT, and Mech. Fuel Pressure). Happy with them all. Got the Gauges in earlier this month with the help of my local TDR chapter members (thanks again guys!). Next weekend did the LP install. I chose the mechanical fuel press. gauge and ran the fuel into the cab. I have a shut off valve on the gauge fuel line in case of any leaks and used a heavy duty hose rated for 200 psi.



4. The pump install is not difficult at all. Towpro had some good instructions that I followed with no issue. The pump costs around $150. 00 at the Cummins dealer. The Dodge dealer in considerably higher. The only thing to look out for on the new LP is the wiring harness from the bottom of the LP to the top. The new LP have a removable harness while the old ones (like mine) were hard wired to the pump. I had to buy a harness for $10. See this link for Towpro's LP install instructions:

https://www.turbodieselregister.com...did=42047&highlight=lift+pump+change+less+min



5. Typical pressures are:

Idle: 12-15 psi

Cruising: 12-14 psi

WOT: Anything above 10 psi

The pressures vary depending on how clean the fuel filter is, how good the pump is, and temperature.



6. Go with a fuel press. gauge for peace of mind. If the dealer does not swap the LP for you, it is an easy do it yourself job.



Good Luck with it,



Jay

 

[Doubleclutch]

Adding just a tad bit more to the above. Having just been there, I noticed my FP gauge (westach) was dropping over a two week period. When it got to ~7# at idle, I took it in under warantee. Dealer checked it out and said "your gauge reads low by 3 #". I asked what the min idle spec was and he said 10#... . Didn't charge for the efforts, but PO'd me by the "at minimum" Return To Service. Two weeks later during our only rain this year at Oh Dark Thirty. gauge reads ZERO on way to work. (Fuel tank was about 1/4 this time ) Pump changed out under warantee, no questions. And to make matters better, the truck is getting traded TO THEM for an 04. 5

Greg

 

[Eventer]

Fuel Gauge Brand

I looked on AutoMeter's Web site since I have the UltraLite gauges for boost and EGT but did not find any fuel gauges in the same type I have that register over 15 pounds of pressure. Is that sufficient? Either that or 100 psi and that is overkill.

 

[JSykes]

0-100 psi is too much range. Ideally, a 0-30 psi would be the best for our application, but Autometer does not offer that in the Ultra-Lites. The 0-15 psi works great for me. With the new LP, I have only maxed out at 14 psi and 9 psi is the lowest. For our stock fuel systems, 0-15 psi is more than adequate.



Jay

 

[JPLB22]

If you want to find out if the LP is moving any fuel at all ( like right now before you get a gauge ) you can do the flow test. Since this is what many dealers do now anyway.



You need either a 11/16 or a 3/4 wrench, I can't remember which since I am banjo-less on my truck . You need to also get some Cummins sealing washers to replace the ones on the banjo you are going to take out ( Cummins part # for sealing washers = 3963983 ). You then remove the banjo bolt on the bottom of the fuel filter and move the bolt and fitting out of the way. Let anything that comes out when you remove the bolt to drain. Then set up something to catch the fule with. Now just bump the starter and let the catch fill up with fuel ( hopefully anyway ), anything less than 45 oz. is what the dealer will replace the pump for.



Jeff