Lift pump # 4

[Ross]

1st original equipment pump died @ 40K. Replaced under warrantee (they let me put it on). 2nd pump died at 88K (April 2001, and they let me install that one too). 3rd pump died last week at 108K. They won't warrantee this one because the truck is out of warrantee. I asked "what about the part? It's only 1-year old, and 20K miles on it?" Tough. My problem. But they offered to sell me a fine replacement unit for 356. 00!!!!!!!!



I called Cummins and they told me the nearest parts distributor was Hobbs Diesel, Hobbs NM. I called them, they had one in stock, and it's 145. 95. It's going in today. The guys there are great, and they even knew that there had been several revisions to the lift pump, and had the latest version on hand.



The only bad thing is that I know I'm replacing a bad pump with another P. O. S. that won't make it 40K. I guess every third fuel filter, I should get in the habit of also replacing the P. O. S. lift pump .

 

[KatDiesel]

Why not add a pusher pump, or move the pump back by the tank? Thats the common solutions. I chose the pusher pump route for now.



You obviously know throwing more pumps in the stock location won't help much.



With your mods I am kinda surprised they gave you three lift pumps.

 

[Alan Reagan]

I would take a serious look at the voltage at the lift pump. If the voltage is running low, that will take out the pump. Even with the mods, the pump is a steady rate pump. Something is causing it to go. Check it unplugged and then plugged up. Probably the only way you can do it is with a dental pick probe to prick the wire.

 

[csutton7]

i personally don't like the pusher pump idea--I know some guys are having success, but in my book the only true success story is ynott's setup as it's going on 2 years all the others using a pusher pump are recent installs---you ask what's my reasoning--if one pump fails you're dead in the water unless you've done some creative plumbing to bypass the dead pump before hand---just a heads up---the lift pump issue is still not figured out and it may be some time before it is---ynott's success is the best going on any pump setup---I would suggest relocating a single pump back by the tank somewhere and keep a spare on hand-----chris

 

[KatDiesel]

Originally posted by csutton7

if one pump fails you're dead in the water unless you've done some creative plumbing to bypass the dead pump before hand---just a heads up

On my truck Aeroquip lines on both pumps, fitting in glove box. Rear pump fails, bypass it, stock pump fails, bypass it. Sure maybe its overkill but sure does look pretty.

 

[abledog]

Someone educate me. Are all of these lift pumps dying from the same problem or are they all failing from different problems?



I have 43,000 miles on the orignal pump and its still going strong. I feel like I need to start gathering spares.



Terry

 

[DEZLPWR]

I believe Steve St. Laurent has 60,000 trouble free miles on his pusher pump setup. I have the same setup that he does, but mine was just recently installed, so we'll see... .

 

[Ross]

New pump in.

Installed the new pump. It is the "latest" part number, according to the guy at Cummins, and other threads on this board. It shows 15-16 psi at idle, and doesn't pull down below 9. These are the best numbers of any of the others. Kat, I will seriously consider a pusher, but had places to go, and had to get the rig back on the road--couldn't wait to order fittings and other parts necessary for the conversion. Also, it appears the jury's still out on the "right" pusher pump. Several members here are using several different pumps, Holley, Mallory, Barry Grant, and others with mixed results. I'm not sure which one to use, when converting.



I have a confession to make... ... ... OK, here goes..... I once owned a 6. 5 Chevy TD. It had an in-line lift pump mounted down on the frame. While the truck had it's weaknesses (very weak!), the lift pump lasted over 150,000 miles. I think I replaced it shortly before trading the truck. I'm wondering if anyone has considered on of these? Very simple install, very compact. It looks like an in-line fuel filter. I could be wrong (8 years ago), but as I remember, these pumps just might be ok, provided the pressures are sufficient. I doubt they would work for High HP applications, but for a trouble-free stock replacement, they might work.

 

[jbone]

Ross, I'm with you--just turn over 42K and fuel press is starting to be very low in morning and jumping around. . taking to stealer later in the week for first replacement--hope we have this problem figured out by time I start traveling next year, but will probably carry spare from Cummins just in case... . R, J. B.

 

[KatDiesel]

Re: New pump in.

Originally posted by Ross

Also, it appears the jury's still out on the "right" pusher pump. Several members here are using several different pumps, Holley, Mallory, Barry Grant, and others with mixed results. I'm not sure which one to use, when converting.

All of these pumps are used as a single pump.



I have a two pump "pusher" setup, the stock on in stock location. And then a Carter 4600 back by the tank. So far there have been very few documented "failures" on this type of system. Is it best? I don't know..... but its an option worth looking at.

 

[Evan A. Beck]

Ross,



I have worked on countless 6. 5's, and you're right--the pump is fairly reliable. In fact, I have only had to replace one. Most of the time, it's that stupid oil pressure switch on the back of the cylinder head that fails. I have probably replaced 10 of them in the past year.



The only thing about this pump, is that is is low volume/low pressure. I doubt it would be able to feed the VP44 in stock trim, let alone mildly 'tweaked. '



I have had excellent success with my Carter 4601HP on the frame rail for the past 30,000 miles. Pressures have remained constant. No, I am not using a pusher pump, just a different pump mounted in front of the tank. The key to all this feul pressure crap is SUPPLY to the lift pump. I have found that going to a minimum of 3/8" ID from the tank to the pump is necessary to prevent fuel starvation. On the bigger trucks & motorhomes I have worked on, the supply line to the lift pump is never smaller than 1/2". Not once have I seen fuel pressure below 12 psi on an ISB equipped rig with the larger lines. Remember, this is on a 30,000-40,000 lb vehicle. On 8. 3s and larger engines, the supply line is 5/8".



Food for thought, eat up!

 

[15w40]

I just went outside and measured the height of the lift pump off the ground and it is at about 28”. The bottom of the fuel tank is about 20” off the ground. This tells me that worst case, with a low fuel level the lift pump has to suck fuel only 8” and if the tank is full, the pump is being gravity fed.



If Evan is right about the pump needing a larger supply line then I wonder if just changing to a ½” line would be the answer??? (And never running low on fuel may help)

 

[Mark_Kendrick]

I started a new thread about removing the banjo bolts...



http://216.235.147.117/forums/showthread.php?s=&threadid=41657



I saw a 1-3psi incease in pressures by reducing restrictions in front of the pump.



the stock carter pump does not normally fail mechanically. . they usually fail electrically. so, I think starvation is less likely a cause than overloading.



the 4601HP and the stock liftpump are almost identical... same manufactureer and case/mounts.



FWIW,

Mark

 

[Cobra]

lift pump

Abledog



Terry you didn't mention if you have a fuel pressure gauge. Do you? If you do what pressure do you have a idle and at wot?

 

[Mark_Kendrick]

Originally posted by abledog

Someone educate me. Are all of these lift pumps dying from the same problem or are they all failing from different problems?



I have 43,000 miles on the orignal pump and its still going strong. I feel like I need to start gathering spares.



Terry

Some get lucky... most don't. You need a FP gauge to know for sure. Your stock pump may pull like new until the moment it dies or it may do so gradually.



Mine ran strong to 35,xxx mi. Good one minute dead the next.



I think the problem is/was with the motor on the pump. I was able to cycle mine and get it to work for a while. mechanical failures probably wouldn't act this way.



Later,

Mark