Diaphram lift pump failed

[Jgolden]

No sign of spring here so I thought I would remove and check the diaphram lift pump. The prime lever didn't seem to work, and lots of discussion here about weak lift pumps.

I have a walbro electric at the tank.

The pump arm was almost impossible to move. Not sure when it failed but my guess is way back.

The electric pump must have been pushing through the lift pump, and last trip I could maintain 65 on a level road(towing car) but lost speed pretty quick on short steep hills.

No doubt the dead pump was an obstruction but not sure how much. Could be the electric can"t deliver enough fuel by it's self. It's pretty far back (20ft)

I get to choose Bypass and use only electric. Low pressure piston pump. New diaphram pump.

Any recommendations appreciated.

Thanks

 

[JLEONARD]

You can probably just bypass the lift pump and use the electric. Make/buy a plate to seal off the block, change the plumbing and go.

Is the electric easy to access/change if you need to?

 

[cerberusiam]

If you go with the electric pump you will most likely have to plumb in a regulator also. Depends on which model Walbro and the pressure it is putting out. Your diaphram pump is probably limiting the pressure now.



Go with the piston pump and its just changing a few parts. Your choice.

 

[JSchlachta]

What are the signs of a lift pump going out? will it affect power at higher RPMs?
I replaced the lift pump two years ago and with my POD injectors I get lots of smoke at higher RPMS like 2800 to 3000, running 30 to 34 psi. EEGT temps are not bad though? any thoughts may look at doing the low pressure piston pump next.

 

[Jgolden]

Jay, I think I'll use the eletric alone first and see how it works.

It is listed at 7psi and it shuts off at pressure if run when the engine is not running.

Easy to change if I put a shut off in the line.



The piston pump sounds like a good choice. Am I correct to say I need the lower pressure version ? I read that someplace.



I got the old diaphram pump lever to move a little, but then it sticks and stops. If it had been the only pump in the system it might have worked off and on, but not well or for long.

No test drives till the next snow storm goes by and the salt washes away.

Thanks

 

[JLEONARD]

7 psi is perfect.

Take a test drive to NW Ct. We'll get that puppy running sweet.

 

[PToombs]

Joe, if you decide to go with the piston pump, let me know. I can get you a good deal!

Do you have a pressure gauge? That will tell you quick if the one will do it!

 

[Jgolden]

Jay, that sounds like a good idea. Road trip to CT.



Pete, that sounds like a good idea on the pump also, I'll let you know.

Hmmmm fuel pressure gage. That would have made sense. You mean check it out with the right tools? I don't have a gauge but I have a relative up the road who has every tool known to man and spent 35 years as a Cummins mech.

His advice is always, "come see me when your ready to do it right". What fun is that.

Thanks

 

[dpuckett]

No, not for testing purposes, to add to the collection on the dash, A-pillar, and under the dash that you're suposed to already have (pyro, boost, tach, trans temp, fuel pressure, volts, oil pressure, and how long til your next fart). I use mine to limit right foot input to keep from starving the VE for fuel. Even with my modest fuelling, I can still suck it down to nothing.



Daniel

 

[JLEONARD]

I can still suck it down to nothing

Man, I love a guy that leads with his chin... so to speak that is... :-laf

 

[DonTX]

Wow, humor even! My two cents worth, of course get a gauge! If you look at the diaphram pump, you will see it makes almost no restriction, so I would suggest that perhaps the electric you have is not sufficient. I replaced my diaphram pump (the washer on the end of the shaft had pulled off the shaft). The diaphram pumps are inexpensive and easy to replace, and after all, Cummins decided that was what is needed. In some installations the VE pump uses no lift pump at all, there is one built into the VE, my motorhome ran quite well fuel wise with the lift pump non-op. Specs call for limit of pressure on this model, so you may want to stick with Cummins rules and limit the pressure if you go with the more expensive pump.

Unless you are needing more fuel than stock, my recommended option would be to stick with the diaphram pump.

You may be into the same thing I was, in that the lack of a lift pump contributed to failure of the IP at only 40k miles, seems like it overworks the IP to "suck it down to nothing. "

 

[Jgolden]

Thanks Don. Good info.

Snow,Ice and Sleet, and now talk of another storm on Sunday, so my testing is delayed.

I live in what the weather people call "higher elevations" and the salt just keeps on comming.



I'll withold comment on the question of suction. I go right through Cape Girardeau on the way to visit my daughter in Oklahoma.

 

[DonTX]

I sure feel for you (but can't quite reach you). Temp here is overcast, slight breeze, 80 degrees! Do you know which way is south? :-laf

 

[PToombs]

Even with my modest fuelling, I can still suck it down to nothing.



Daniel

I can still suck it down to nothing

Man, I love a guy that leads with his chin... so to speak that is... :-laf

I'm going to do something unusual! No comment! :-laf