Lift Pump replacement. How hard?

[Prostock]

I am a new board member, and also a new Cummins diesel owner.

I had my 94 Ram check out by a local shop since it doesn't seem to have the power I expected pulling my 68 Super Bee, and car trailer.

They adjusted the valves, and said the lift pump was out of spec.

I'd like to replace it, and in looking at my service manual, it doesn't look to be all that bad of a job, but I thought I would ask on here, in case anyone had any tips to make the job go easier.

TIA



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Tom
1994 Ram 2500 4x2 CTD Stock for now.

 

[HEMI®Dart]

Tom, I did mine a long time ago. It was not bad.

See this thread for more info:
https://www.turbodieselregister.com/ubb//Forum1/HTML/003929.html

 

[Prostock]

Thanks for the fast reply. I plan to stop tomorrow and get a pump if they have one in stock. Hopefully get it on this weekend and see how it runs.

 

[Jeff Knight]

Hi Tom,

I use to live about 30 miles south of Pitts. If you need anything for your truck you have a great place in Mt Pleasant. They sell performance parts for our dodges. They even install what they sell. You can contact them at smokindiesel.com Good luck with your lift pump. Jeff

 

[Prostock]

Thanks Jeff.

I was recommended another place that is closer, but I am not happy with the work they have done to the truck so far.

 

[Cooker]

How did they determine it was the lift pump. I ask this question for two reasons, 1 - I want to know how to isolate the lift pump to test it, and 2 - if the only checked the fuel pressure it could be a bad overflow valve causing it to be "out of spec"

-Ryan

 

[Prostock]

Ryan,

That's a good question.

When I picked up the truck, I asked the same thing.

The mechanic that did the work wasn't around, so they didn't know the answer to that or to many other questions I asked, and still haven't got answered. That is one reason I am not so happy with my local shop.

I'm only replacing it because it looks original, they said it's out of spec, and because it seems that they need replaced somewhat often.

 

[Cooker]

Prostock,
On the 12v engines the lift pumps don't need to be replace often. The 24v's are a different story. The number one problem with the fuel system on the 12v is the overflow valve, not the lift pump.

This is just my $. 02, but the overlfow valve is cheaper (~$80 from Cummins, ~$45 from Piers) and much easier to replace than the lift pump.

I talked with a gentleman at a shop one time and he said that 2 out of 3 trucks that came into his facility for power mods needed a overflow valve first.

-Ryan

 

[Deezul1]

Check fuel pressure first and if its low you can stretch the overflow valve spring so that it measures . 550 and replace it and check pressure again. If its better get a new overflow valve. I have done this on both of my trucks and the power came back real good. Oops saw you have a 94, may have one piece valve so no stretching, but I bet you have a problem with it and its way easy to change. Its built into the hold down bolt in the banjo fitting on the injection pump. Its the return line which is on the engine side of the pump and right at the front on top. Put a rag under the fitting to catch the sealing washers when they fall.
Good luck


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97 SLT Laramie CC 5spd, 3. 54, Ranch Hand front and rear. Gauges, EGT, Boost, fuel pressure, oil temp,indash CB, custom switch mount-6 switches BD brake extra fuel tank 45gal. Oh oh dang cat fell off, took the muff with it. Member NRA/USPSA

[This message has been edited by Deezul 1 (edited 05-30-2001). ]

 

[DieselB59]

Usually, when the lift pump goes bad, it'll puke fuel out from the plunger button as the seals will be the first thing to go. Otherwise, I must agree that it'll be the overflow valve that is bad and a very poor diagnosis on the shop's part. Sounds like they were getting ready to reel you in. Let 'em know that you're not a sucker after you fix it yourself.

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Chris Timochko
*Association of Diesel Specialists Certified*
AUTO WURKS DIESEL R&D TEAM
1997 5sp 4X4, Rhino Linings, Espar Heater, A. W. D. HX40 turbo, ATS 3pc Manifold, BD 4" Brake, Marine Compression, A. W. D. Custom Tuned Injection Pump, A. W. D. Intercooler, A. W. D. /Mallory Fuel System and Braided Stainless Lines, A. W. D. 370B Injection Nozzles, Delivery Valves, Governor & AFC Spring Kit, Psychotty Air, NOS Diesel Kit, A. W. D. 6" Chrome Exhaust System, BD No Smoke Valet Switch, McLeod Dual Disc Clutch, Mag-Hytec Rear Cover, Cummins Chrome Kit, Optima Red Tops, Hadley Bully Horns, Hurst Line Loc, Goodyear Wrangler AT/S 305/70/16s. 15. 50@97mph on Goodyear All-Terrain tires. Dynoed at Ida's: 435 hp at the rear wheels.
****************************************************************************
Project U96 - 1996 3500 2WD racer. A. W. D. Marine Ultra Low Compression, A. W. D. Teflon-coated Pistons, A. W. D. High Lift Camshaft, Ported and Honed Cylinder Head, Intake and Exhaust manifold; A. W. D. HX40 Turbocharger, ATS 3pc Exhaust Manifold, A. W. D. Water Mist Injection, A. W. D. Custom Fabricated Fuel System, Race Spec A. W. D. /BD P7100 Injection Pump, A. W. D. Custom High Flow Fuel Injection Nozzles, BD Auto transmission and Custom TC, Weld Draglites, Goodyear Eagle Drag Slicks, 5" Single Stack Through The Bed, Mag-Hytec on Rear and Transmission. 11. 54@115mph

 

[Blakers]

What kind of fittings do I need to check the fuel pressure and where do I attach it? I have a gauge for checking fuel injected gas engines and it has an attachment for shrader valves. I am very suspicious of my engine having low feed pressure problems as it stumbles and smokes white at 2200 rpm. Even notice a slight miss around 1000 rpm with no load. Seems fine under load though.
Thanks, Blake

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"Blue Bomber" ... Blue & Silver 1995 2500 Laramie SLT, Regular cab, 4x4, a/t, K & N air cleaner, 16 cm turbo housing, 290 hp/700, 3. 54 LSD, 265-75/16 (for now). Steam Engineer and NRA Endowment member.

 

[Prostock]

I don't know what to do now after reading this.

I'm sending a copy of the link to this thread to the shop that did the original work.

I had planned to stop at another Cummins dealer at lunchtime today to pick up a pump, but now I don't know.

Should I give them a shot at diagnosing the problem? They're $85/hour, so I know it won't be cheap just for them to even look at it.

I don't want to just start throwing parts at this truck until it's fixed.

Tom

 

[RHARVEY]

I had the lift pump replaced on my 12v 3 weeks ago. I was loosing prime when it was parked up hill over night,level or down hill it was ok.
I called Cummins in Indiana, and the first thing out of his mouth when I described the problem was that a seal in the lift pump was going bad.
I was on vacation so I decided that instead of taking the time, I spent the extra and had them put it on. After it was replaced, I have not had the problem again.
If your is like mine, it looked like a pain in the rear. But also I learned that if I were to do it, remove the solid line at the top of the pump instead of trying to remove it from the top of the pump. Also instead of having to find top dead center to intall the pump, hold the pump in place and have someone rotate the motor until the pump drops into place(low side of the cam lobe).
Have fun replacing it...

Rick

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RICK
97 2500,CC,5 SPEED, 3. 54 Limited Slip,Psychotty System,K&N, Pre-Turbo ISSPRO 3" Pyrometer & Boost Guage,Silencer Ring Removed
15,000 RBW 5th Wheel Hitch,25' Excel 5th Wheel,Rancho RSX17000 Shocks,Amsoil Dealer,Straight Piped

 

[Prostock]

This is the response I received from the shop:

the pump specs are 25lbs at rated RPM. Your made 18lbs and dropped to 12 under load. This test was performed by the service manual. It is done by installing a pressure
gauge in the pressure line after the pump. As far as the forum discussion, overflow valves cause smoke, miss, roughness and low power problems. Seldom effect the fuel pressure and the manual does not address the valve in low pressure troubleshooting. There was no mention of a smoke problem, roughness or miss when we spoke to you so we did not try replacing the valve. This valve _has_ been a problem over the years causing the above mentioned problems.

This shop comes highly recommended to me. What do you guys think?

 

[Joe G.]

One thing to consider is that some of the '94s and early '95s normally had lower fuel pressure. Have you experienced a decline in power lately? If not, then I would not just replace the lift pump on a WAG. A stock '94 is kind of low powered to start with. If it runs good except for less power than you expect it may be normal.

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Joe George
Eureka, CA

'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,DTT TC/VB,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver, KDP 160,000-NM-WT Insurance

 

[Prostock]

I just bought the truck, so I don't know if it's normal or not.

I know it doesn't seem to tow my trailer up hills any better than my 89 GMC 350 conversion van does.

It doesn't feel right though when towing. When pulling a hill, it actually feels like it has more power pulling a hill when I back out of the throttle a little bit than having my foot to the floor.

 

[Joe G.]

If it's an auto trans then it only has 160 HP stock to begin with. I dunno if I would just replace the lift pump until I knew a bit more about its performance. If it's still completely stock you might try sliding the torque plate forward and see what happens. If that helps then the lift pump is supplying the fuel ok since that will allow more fuel at full throttle. There are a few simple things to do before spending any money. Check to see that it is really getting full throttle. Check the intercooler hose clamps and tighten them if needed. If the lift pump is not leaking it is probably ok. It's a pretty simple gadget.

 

[Prostock]

Frank,

Like I said in the first post, this is my first diesel.

This forum has taught me a lot. That is why I joined. I still have a lot to learn though.

 

[Joe G.]

Go for it Tom,

That's the way the rest of us learned. Sometimes you will blunder, but that's how you learn. Try not to break anything expensive while you are at it. #ad
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I get a lot of satisfaction in doing my own work if I possibly can. At least I know who to blame! #ad

 

[Prostock]

I just wish I could get a good baseline to work from.

This shop has a good reputation, so I'm taking it back next week to have the work done.

I just bought this truck, and went to the NASCAR race in Charlotte last weekend, so funds are a little bit tight right now, but I need to get it running right soon.