Engine/Transmission (1998.5 - 2002) Lift pump thoughts.........

[Lsfarm]

Let's talk facts not Engineering theories

Fact: cheap well pumps suck from shallow wells, deep wells get submersable pumps which PUSH the water to our homes.



Fact: Gasoline fuel injected cars that had remote fuel pumps that sucked from the tank had high failure rates [VW rabbit,Jetta, BMW 320 etc].



Fact: the new versions of the above cars have in-the-tank submersed PUSHER pumps that last virtually the life of the car, unless they are fed contaminated fuel. And this is with Gasoline which has very little lubricating ability compared to diesel fuel.



Fact: My virtually dead second factory lift pump [o-7psi at idle] came to life and survived another 7000 miles when fed fuel from a frame mounted pusher pump. It was fed 7psi, and in a few seconds would wake up and run the pressure to the top of the gauge 17+psi. Once the pusher pump was removed for some warrantee work, the factory lift pump was DOA within five minutes at the dealer. It was warranteed, I'm now on my third lift pump in 21K miles.



Fact: in every aircraft that I'm type-rated in that uses hydralic pressure, [to operate various systems] has hydralic oil supplied to the electric or engine driven hydralic pump UNDER PRESSURE. It is proven that if the supply oil looses it's head pressure, the pump will fail almost immediately.



Fact: I don't believe that there has been a failure of a factory lift pump when it has been fed fuel by a pusher pump. There have been untold numbers of factory lift pumps fail when run in the stock configuration [sucking fuel uphill from a tank 6-8 feet away.



The bottom line: with the expense and fragility of the VP44 hanging over my head, I will continue to keep a pusher pump feeding the lift pump.



Last fact: Engineers 'engineered' this setup, with some help from penny pinching marketing and accounting at Dodge.



Theory often is not supported by reality once the parts are on the road and failing at a high rate, then new 'theories are created' to cover the 'new reality'.



Road tested and proven beats theory every time.



My opinions and experience: Greg L

 

[15w40]

Lsfarm, Please don’t take my response as a flame. Having these discussions benefit everyone by getting the juices flowing. I have to respond to your post.



Shallow wells can use a surface pump because they are shallow. Deep wells require a submerged pump because it is not possible to draw water greater than about 34 feet, where a perfect vacuum is formed.



Older carburetor cars used an engine mounted diaphragm pump to suck gas from the tank and lasted a long time. Modern fuel injected engines require much higher fuel pressures and tank mounted pumps have proven themselves. I have owned an ‘82 Audi with an electric pump mounted between the tank and engine. This “lift” pump lasted 225K miles and failed because of an internal check valve spring. This fuel system was almost identical to the one in the Jetta and the problem with the Jetta was caused be the fuel pump relay getting wet from leaks behind the dash.



If the lift pump on your truck could not keep up with the demand of the VP44 your pressure would be zero. Adding a pusher pump bumped up the volume to the point where the VP44 was not using all the fuel and you saw a positive pressure.



Aircraft hydraulic pumps that have failed because of lack of pressure are something that I am not familiar with. Could it be that without a positive pressure they lacked lubrication?



I agree that far too many factory lift pumps have failed. There was a poll not too long ago asking how many pumps have failed after adding a pusher pump. Unfortunately there was not a lot of data, but there were a couple of pumps that died after adding a pusher. It was thought that these pumps failed because they were dying before adding the pusher. Maybe the fact here is the pusher cannot save a compromised pump. How do we know it can protect a new lift pump?



I fully agree that anything that can protect the expensive VP44 is a good thing and if the redundancy of adding a pusher pump helps, I am all for it. I am just trying to find a long-term solution for this problem.



The engineers who “engineered” this set-up are definitely looking for the cheapest way to get the job done. That is the only way they can remain profitable. I will bet they knew that there would be problems with this system but decided that repair costs would not be bad, I wonder if they still think that is true? One poster, Even Beck, said that in motor homes the same lift pump is used in the same location with no problems. The difference is in the size of the fuel line from the tank. (This supports the theory that reducing the vacuum to the lift pump might help. )



I do not consider there has been a sufficient test of the pusher pump to state that it is the final answer. I am looking for a long-term solution, greater than 100K miles.



Thanks for challenges to my thoughts and theories. It keeps me on my toes. I’ll have to take my medication now.

 

[TPlasek]

[15w40]Inside the lift pump is a constant volume vane pump. A spring-loaded spillover valve sets the output pressure internal to the pump. [/15w40]



I have a lift pump that produces 7 psi when you turn the key on and drops to 0 after the motor starts. Toady I took the top cover off my lift pump. I saw the 4 blades of the vane pump. I can not find any defects in the vane or the housing that the vanes spin in. I pressure checked the relief valve and it opens at 12psi, so that was not the problem. The brushes had lots of life left in the but the center portion of the electric motor, the part where the brushes ride, was very worn. (I'll post pics this evening) I wished I had a way to fire up the electric motor and do an rpm, current, and voltage test, but I do not have the tools to do so. It looks like in my situation the motor portion of the lift pump has failed and not the pump portion. My question is, could this problem be caused by low voltage or vibration??? Does the pusher pump / larger fuel line ease the load on the motor thus making it last longer???



I have have pictures of the lift pump taken apart. I will post this evening.

 

[15w40]

Tplasek, I don’t know the year of your truck and clicking on the “profile” button doesn’t help me, hint - hint, but in model year 1999, DC had a general recall for lift pumps showing low pressure. They had determined Carter changed the design of the pump and eliminated the bronze motor bearings. The new pumps used the pot metal castings as the bearings and they were not holding up. I believe this was an engineering change to save some money that backfired. If the motor bearings get sloppy I can see how the motor may slow down as it hits the field magnets or loses electrical contact with the brushes and causes the pressure to drop.



If your truck is a recent one, than the problem you see is a new, and another for me to chew on.

 

[Lsfarm]

Pump Cavitation and failure

Carbureted cars had rubber diaphram suction pumps, and they only created about 4-8 psi at best, since the needle and seat in the float bowl of the carburetor couldn't control more pressure.



Diaphram pumps were made to suck fuel, but had their problems with vapor lock. Often electric pusher pumps were or are added back at the tank to push fuel to the diaphram pump so that the fuel won't vaporize in the fuel lines.



My second lift pump would fluctuate between 0 and 7 psi with the engine at idle, and zero at WOT. With the pusher alone, the pressure was a rock steady 7 psi, even at WOT. When the pusher fed the lift pump, the combined pressure was far greater than the sum. The lift pump liked being fed fuel under pressure. Having a head pressure makes any vane pump more effecient [sp?].



The aircraft hydralic pumps would cavitate [suck so hard they created bubbles in the intake line] and the result was a trashed pump in moments. Jet or turbine engine bleed air is often used to pressurize the oil tank so that there was positive head pressure to the pump.



Pumps like head pressure, unless they are designed to suck. Our lift pumps were not designed to suck fuel as far or as high as they must in our trucks. The pump needs help, and a pusher pump does this.



I believe that the pusher pump on our truck's frame rail [which is a virtual gravity feed] will feed the factory lift pump [provide head pressure] and prevent cavitation and the failure of the lift pump. If my pump which was virtually dead was able to keep running with the help of the pusher pump, I'm sure that a good lift pump will last a very long time when fed by a pusher pump.



The only other answer is to put a submersed pump in the fuel tank itself. I'm not sure why this isn't common practice with diesel fuel. Or we could remount the fuel tank inside the bed, and gravity feed the lift [transfer] pump.



The pusher pump system works, plain and simple. It is noisy though.



Greg L. the Noise Nazi

 

[M Evan]

Lsfarm just Q. Will pusher pump void the warranty on related parts ? Is pusher pump noisy ?

M

 

[Lsfarm]

Warrantee and Noise

Whether or not the pusher pump voids the lift pump warrantee is pretty much up the the dealer. I know of several lift pumps which were warranteed even though the truck had had a pusher added after the factory pump died.



What occured was the lift pump died, the pusher was added right away so the truck could be driven safely while the dealer ordered in the replacement pump. The pusher pump was noted when the lift pump was replaced, and the dealer said it was a good idea, at least the VP44 wasn't being run without feed pressure and cooling.



Not all dealers would do this, some may decide to cancel some or all warrantee.



My pusher pump is noisy by my standards; I can hear it when I step out of the truck, it sounds like a small swarm of bees under the driver side quad door. My Cummins has a lot of sound proofing on the block and oil pan to quiet it down.



I cannot hear the pusher inside the cab, but my cab has extensive sound proofing and panel deadening work done on it. I only find it mildly annoying to hear the buzzing from outside. .



Any standard Cummins truck would drown out the pusher pump noise with ease.



I've been rather strong minded about pusher pumps since it IS really needed on our trucks whether stock or modified, there are too many people being stranded and/or having to pay big dollars after the warrantee has run out. Just a simple $150. 00 add on pump would fix the potential for failure.



A lot of people read this forum who will never add any performance modifications to their truck, but are interested in longevity and reliability.



That is why I objected to the comment that a pusher pump is not needed for a stock truck, and that a pusher pump won't aid in lengthening the life of the factory lift pump. Those statement fly in the face of my experiences and training, and physics.



Some lift pumps may last a long time, some die very soon, there have been polls for both situations. The polls have shown very short life: 3500 miles and very long life 100K+ miles. I'm on my third pump at 22K miles.



Opinion based on experience: Our trucks NEED a fuel pressure gauge, and a pusher pump to prolong the life of the lift pump. Also: don't run your fuel tank down to below 1/4!! The fuel pickup can become unported very easily with the long flat bottom of our fuel tanks, and feed air/foam to the VP44 [personal experience].



Greg L

 

[tmacc]

Just in case anyone is interested. Since the dealer and I couldn't agree on what low pressure is, (I was getting 1-2psi at wot), I put a $80 Carter 4601 15psi pump (from summit)back by the tank and eliminated the stock pump all together. I get 15+psi at idle 13-14 psi at cruise and it never goes below 10. 5-11psi at WOT. I have talked to other members that have put new DC stock pumps back at the tank and get similar reading. It's only been in about 2. 5 months, so we'll have to see how long it last, but Mopar-Muscle used the same pump in the stock location and got 32k out of it. I ran new AN-6 fitting and 3/8" fuel line from the pump to the filter housing. A little off the subject, but I thought some newbys might like to know.

Tom

 

[4020Deere]

I may have found an alternative to the Carter lift pump problem. I work for John Deere and we use the VP44 pump on our 6. 9L marine engine applications. In looking through some of the specs, we use 2 different lift pumps. The first one is a 12volt one that sits on top of the fuel filter. This setup looks to be pretty compact, however, you would have to use the JD filters with it. The second coice is a 24volt electric pump, that is about the same size as the current Carter pump, and could be bolted on the same location. It is not a part of the fuiel filter housing. I would think this could be converted to 12volt. Anyway, I am having some people check on these with prices from the supplier (Stanadyne). I will have to see how the cost is before I would decide to switch. I do know that these have been very good pumps for use with the VP44, and they are using it in 300 horsepower applications just fine.

 

[Big White Beast]

Some good info here again........

Well I just changed my fuel filter last week and ever since I've been able to draw down the pressure. 25K on the truck is why I started worrying. Now I can draw it to 8# according to my gauge. I've never been to happy with the response time of the Stewart Warner senders. So it's probably worse than it reads.



Anyway, Smokin Diesel.com has a fuel system upgrade that looks very nice. It's the price that bothers me. Although for 2 pumps and the lines I'd probably spend near that much and waste lots of time rounding up parts.



What do you guys think of the set up they're selling.



http://www.smokindiesel.com/Dodge/24_valve/fuel_system_24v.htm



Garrett

 

[M Evan]

Don't look so bad pricewise, if you want to buy comparable system from http://www.jannettyracing.com/dodge.htm ,you will pay more.

M

 

[Mike Ellis]

Time for some stupid questions from a 12V guy: What kind of transfer pump setup do the Powerstroke trucks use? Do they suffer from a large number of failures like the 24V Dodge trucks do?



Since the Powerstroke is a larger displacement engine, one would suspect that they would need to flow larger quantities of fuel. If they do have a more reliable pump setup, how hard would it be to put on a Dodge truck? (yeah I know it's sacrilege but what the heck. . )

 

[HVAC]

Ford Fuel Pumps

Ford uses a much better pump IMO.

Unfortunatly its pressure range is much to high for our 24v engine.

I don't hear of any problems with their pump, as it should be.

 

[BK]

Mike, good question. One that's been bouncing around my dead gray matter as well.

 

[M Evan]

What is the price for Ford pump ?

M

 

[radar doctor]

Pulsing from the 44 Pump

Ok I like the theory on the pulses from the 44 hurting the Lift Pump ... But Has any one wondered or thought about why we dont have the some problems with the pumps on the 12 value engines? Don't they Pulse too? I know they are different but could there be something in there somewhere that could lead to a suloution to our LIFT Pump Problems on the Newer Trucks???Any Ideas???

 

[HVAC]

Pumps

The 12v pump is mechanical like your 327 chevy was. Just an arm that is pushed by a lobe on the cam. Very simple and hence reliable.



The fix for our 24 valve engines is to use another pump. IMO it's not the environment the pump dwells in that's causing premature failure, it's just a POS pump.

 

[BK]

HVAC,

think your 1/2 right. . POS pump FOR the application. If it was in the tank or close to the tank and gravity feed it would be fine.



It seems the DC engineers pushed the operating parameters for that pump in an effort to meet cost targets and not have to incure the costs of designing a pump for the application.

 

[tmacc]

BWB and M Evans,

$400 and some bucks for a kit??!! Why two pumps if your going to all that trouble? I have a grand total about $160 in my set-up, maybe a skosh more. That's an $80 pump + frt. , one $10 adapter from Summit to go into the stock filter housing, about $40 in Parker fittings and Pushlok fuel line, some wire from Wally world and a $6 relay and connectors from Radio Shack. You could save a few bucks by using less expensive fittings. This is not rocket science. LOL If you want details, PM me.

 

[lsenus]

Speaking as a stock truck guy, I sure wish I had a pusher when my truck died 2 weeks ago. Thankfuly I was still under warranty. The lift pump diead and then the injector pump!

As far as a dual or remote pump setup goes, I'm looking into Aeromotive pumps and regulators. I've got a string of emails with thier tech folks about using thier pumps with diesel. I'm looking at a pump setup that generates 18-20 psi They also have a regulator that is adjustable from 3-20 psi with the std spring, and 20-65 psi with the higher spring.