"Just like 3/4 of the people on here, way over my head. There are many people that can understand all of this, its not for me. "

I agree. You shouldn't have to read 15 pages of debate on the merits of lift pumps to select a lift pump. And you didn't. You went out to people in the market and looked what they had and copied them. And there is NOTHING wrong with that. I do the same for stuff I don't know anything about.

However, that is how we got here to begin with. People had lift pump failures and they looked around and saw what someone else was doing (Holley Blue, Carter, etc) and copied them. And that approach has kind of worked, but kind of not, too. Because Dodge Cummins trucks still have a very high lift pump failure rate.

And thus this thread tries to delve into the topic as deeply and honestly as we can. In all the little intricate detail we are picking apart what is good and bad, what matters and what doesn't and MAYBE we will find a better solution to the lift pump problems of the Dodge Cummins truck. And MAYBE next year at this time when someone asks this group what the best lift pump solution is, they will reply Walbro or Bosch or Toyota or who knows. But they won't reply just because, they will reply because they have given it some thought and debate.

 

How long will a Walbro live ?

OK... the Bosch lift pumps in the 99+ Superduties are living for 100,000 or 150,000 miles. Actually I haven't heard of very many failing so I don't know. But the SD guys I hang with haven't had any failures that I am aware of and my truck is the least used at 82,000 miles.

I burnt the Bosch up in my truck doing some stupid high pressure lift pump mods trying to make it run better. I think it burnt out after running for a while at 90 PSI. Then I put the Walbro in and it lived fine at 90-100 PSI. I turned down the pressure after a while because it made no difference.

So, point #1: the Walbro should outlast the Bosch at the same pressure.

My Walbro has so far lasted 60,000 miles at 70 PSI. In the Dodge it will run at 20 PSI average. The Walbro should last 3x (?) longer in the Dodge than it will in the Ford application. 3x 60,000 = 180,000 miles.

I am coming to the conclusion that the Walbro might last 200,000 or more miles in the Dodge Cummins application. I don't exactly know what would wear it out.

Generally it is the motor that will wear out in the lift pump, because all DC motors wear out due to their brushes. But the brush size on the Walbro is immense because it is designed to handle 18 amps peak load and will only be running at 4-5 amps, depending on pressure. And the brushes will be cooled and lubricated by diesel fuel, as will the motor bushings.

So what will determine the ultimate life of the Walbro fuel pump ? I dunno. Maybe debris in the fuel ? The Bosch pump lasts a long time and the Walbro is stronger than the Bosch.

I think the Walbro is an outstanding fuel pump for its price.

 

SD, you're doing a pretty good job of sticking to the facts, so I'd suggest not implying that tenuous link between VP44 failures and the lift pump system. This is perhaps an even bigger source of blind speculation on these boards and vendor sites.

It makes intuitive sense that there are probably a class of VP failures related to suboptimal fuel supply, but that's as far as I'd go based on evidence.

It's certainly prudent to ensure optimal fuel supply to the VP as a measure toward keeping the VP healthy (not that any of use really know what "optimal" fuel supply _really_ is: I sometimes doubt Bosch even knows).

 

My friend works in a fuel shop that rebuilds VP44s. He tells me there are a couple of things that wear in them. Something in the advance mechanism and a bushing that supports the main shaft. He figures the bushing would last a lot longer if the pumps were better lubricated.

Bosch knows exactly why this stuff fails and how it wears. They also make lots of money selling fuel shops new front housings.

Isn't it funny that DC can build all the rest of their vehicles without fuel pump issues, including the fuel injected vehicles that run at 50-60 PSI, and yet the Cummins trucks have issues. I wonder how much money Dodge makes selling fuel pumps and VP44s after these trucks go off of warranty ?

I agree this is off topic and speculative. I won't say another word about it.

 

The thing is that pump could just like any of the other pumps out there and anything mechanical or electrical....just die tomorrow.

If you are going to say 200,000 miles, why not 300,000??? Have you taken your walbro apart and inspected it?? It could be all worn out....or it could be like new. Its all speculation.

What I am not getting right now is what the need for 60psi is? Stock the truck runs 7-9psi all day long. At WOT it drops....thats a fact..solid as a rock FACT stock. If a aftermarket pump runs 7-9psi all day, and stays at 7-9 at WOT, obviously the CP3 or VP44 has more fuel than it could use hence there is a pressure.......a traffic jam if you will....of fuel waiting to get into the pump.

Trying to ram 25psi, 40psi or even 60psi into the pump is like watering your lawn with a fire hose....overkill. Provided there is adequate volume, and it is at a solid pressure.

With my setup now, (had the filter mounted swapped to the in-tank this weekend, just for the hell of it under warranty) and the holley blue with the regulator, the tech and I checked the volume. There is a TON of fuel coming out of the line to the CP3.........A TON! The holley by itself sucking through the in-tank pump off, it was 9psi with the holley regulator. The in-tank bypassing the Holley is 8psi. At WOT, it does not drop one psi, smoke likes a house on fire, and doesn't surge, buck, pop, fart....you get the idea. So now its being said that I need shoot diesel fuel across the shop at some high pressure to keep the CP3 or VP44 full of fuel???????

The diesel tech (who is member on here) and I talked about it for a while. What is the point of the high psi??? On a gas engine, the high psi is needed by the fuel injectors to atomize the fuel, hence the high pressure FI pumps, hence why the rice-rockets and mustangs need it. But on out trucks, we have a CP3 or VP44 to make the pressure for the injectors to atomize the fuel. The LP does not have that requirement...the injection pumps do. Also, keep in mind that the CP3 will only pump so much fuel, hence why there are guys out there modifing them to get more from them, so having a "traffic jam" of fuel, that the CP3 cannot use (being as pressure is measurement of restriction), is like I said...watering your lawn with a fire hose.

I look around, and it been said that the Blue is out of its range (the red is on the low side IMO), but yet I don't see them failing in the CTD in wide margins.

The FASS is simple and a 1-stop shop, and with huge filters........that's its claim to fame. You pay the price of convienience.....period.

There are a ton of pumps, carb or FI, out there on the market.....but the only one that works is the Walbro that has just been found???

 

Higher psi pumps being a Walbro or any other have a much larger margin of safety. In other words, a higher psi pump, say 60psi, in a setup like SD has with his bypass at the cp3 will flow incredible amounts of fuel with such a low load on the pump that theoretically it would live a very long time. You see, even though it's a high pressure pump, it isn't under a high pressure load due to the bypass. Plus it's fuel cooled instead of air cooled.
Look guys, we all have this incredibly powerful Cummins engine between our fenders. More power than most of us need even though some of us want more. There is no reason to not consider that the fuel system should be as potent a combination. I'm gonna go out on a limb with SD and say here that those who use Holley's Blue and especially Red pumps are asking for trouble. Thats just my opinion. I've been researching the fuel pump issues since about a year before I purchased my 05'. SD's knowledge and ideas sound the most logical. I'm not an engineer. I am a tradesman who has been wrenching for about 15years. Kevlar flame suit on...

 

This is part #1. The next post is part#2. Are you guys paying me by the word, the hour or the post ? <chuckle>

"The thing is that pump could just like any of the other pumps out there and anything mechanical or electrical....just die tomorrow."

OK. Lets say it does dies tomorrow. It went 60,000 miles at 70 PSI. Lets say it will live 3x longer in a Dodge because it will run at 20 PSI versus 70. So it would get 180,000 miles in a Dodge. That seems to be better than most Dodge fuel pumps are doing.

"If you are going to say 200,000 miles, why not 300,000???"

I used the pressure ratio and an indicator of the pump life. 70/20 = ~3x. 60,000 miles x ~3 = 200,000 miles.

"Have you taken your walbro apart and inspected it?? It could be all worn out....or it could be like new. Its all speculation."

I'd have to destroy it to inspect it. And in July it still made enough pressure to blow the filter lid, so I expect it will last a while longer.

"What I am not getting right now is what the need for 60psi is? Stock the truck runs 7-9psi all day long."

OK... let me repeat this again. The Walbro is CAPABLE of running at 80 PSI. It would be RUNNING at whatever presssure the regulator set.

Running a pump CAPABLE of generating high pressure is like running a high torque diesel: it is built WAY heavier than a low pressure pump. The brushes on the Walbro are built for 18 Amps. They are bigger than they would be if the pump was designed for 3 Amps. The heat dispation is designed for 0.04 HP of pumping. The armature wires will be larger. The bearings will be stronger.

The Walbro at 20 PSI is just idling. It is loafing. That is why it will last so long.

The Holleys, by contrast, are running flat out. They are running at or above their maximum pressure. (Let alone their rated pressure.) They are drawing 100% or more of their design current. They are running hotter. The brushes are wearing faster.

"At WOT it drops....thats a fact..solid as a rock FACT stock."

If the pressure regulator is moved from before the filter to right at the injection pump, then the fuel pressure will NOT drop one bit, except for the slight amount of error in the regulator itself. That is a fact.

I agree the stock fuel pressure drops. The reason that the stock fuel pressure drops is that there is no regulator in the system anywhere. At idle the stock pump churns away, pumping very little few, but at a higher pressure. The stock fuel pump is working hardest when the engine is idling ! At WOT it pumps more fuel, but the pressure drops. Just when you don't want it to, because that is when the chance of injection pump starvation is the greatest.

"If a aftermarket pump runs 7-9psi all day, and stays at 7-9 at WOT"

I have yet to see a post with a single system that does that. Everyone seems to have 5 PSI of drop from idle to WOT.

Secondly, is 9 PSI enough for the VP44 ? That pump costs $1500ish to replace when it goes bad. Why not give it a few more PSI as insurance ? Why not 15 PSI ? ALL THE TIME ? I mean, if we are going to solve the problem of preventing the lift pump from failing in the first place, why not go one step further and give the VP44 the absolute best fuel feed we can, 15 PSI all the time ?

One more thing. The lift pump doesn't run at the same pressure as the injection pump. There is 5 to 10 PSI drop difference, depending on the fuel flow, fuel temperature, filter dirtiness, etc.

"obviously the CP3 or VP44 has more fuel than it could use hence there is a pressure.......a traffic jam if you will....of fuel waiting to get into the pump."

There is excess fuel available at the injection pump, yes. On the CP3, this is as far as one needs to go. But with the VP44, I get the feeling that the higher the feed pressure, the greater the quantity of cooling and lubrication that occurs. The VP44 doesn't have a lift pump built into it.

"Trying to ram 25psi, 40psi or even 60psi into the pump is like watering your lawn with a fire hose....overkill. Provided there is adequate volume, and it is at a solid pressure."

Nobody is talking about feeding these pumps with those kind of pressures. The regulator will set the system pressure.

I am talking about using a pump that is CAPABLE of supplying those pressures because that gets us a tough, robust pump. Nothing more.

Now... your talk about feeding things with a fire hose brings us to the flow rates of these FASS and Holley pumps. Who, in their right mind, needs a pump that flows 90 or 150 GPH ? Can you show me one Cummins engine that comes close to consuming 90 GPH ? No. Not even the truck pulling engines are there.

However, how many instances can you show me where lift pumps have died or altogether don't get the job done because they don't have enough PRESSURE ? Lots. They are all over the place.

So... the question is, why do Dodge truck owners keep buying high flow, low pressure pumps ? Why don't they buy lower flow, higher pressure pumps ? The later would be a lot more suited to the application.

One more thing. I keep stating the lift pump needs to make 25 PSI. I also state the injection pump should see 15 PSI. The difference between the two is the filter restriction, line restriction and fuel viscosity when cold. So when I say the lift pump should be making 25PSI, that is because I want 15 PSI at the injection pump, all the time, even at WOT.

"With my setup now, (had the filter mounted swapped to the in-tank this weekend, just for the hell of it under warranty) and the holley blue with the regulator, the tech and I checked the volume. There is a TON of fuel coming out of the line to the CP3.........A TON!"

Yep. With a clean filter and warm fuel, at idle. And did you keep any backpressure on that line when you tested the flow ? No ? So you were testing the flow at 0 PSI, but in reality there is about 5 PSI of backpressure on the return line. So your flow test wasn't even valid.

"The holley by itself sucking through the in-tank pump off, it was 9psi with the holley regulator. The in-tank bypassing the Holley is 8psi. At WOT, it does not drop one psi"

Then you have rewritten the physics of fluid movement. When you go to WOT the flow though the lines and the filter increases. And thus it takes more pressure. And if it took more pressure then there had to be a pressure drop because it sounds like your regulator is at the lift pump. Other trucks are seeing more than 1 PSI of flow difference. They they are flowing more fuel too. And when the regulator is moved from the lift pump to the injection pump, the flow through the fuel filter goes from 15 GPH to 75 GPH, in my case anyway, so there is more pressure drop.

"So now its being said that I need shoot diesel fuel across the shop at some high pressure to keep the CP3 or VP44 full of fuel???????"

Well, the CP3 can be run without a lift pump as it does in the Duramax. So there might not be any gain there. However, some of the Duramax guys are saying there is a lot to be gained by putting a lift pump in the circuit. Specifically, going from full throttle to off to full again can cause rail pressure codes, so it is pretty clear the CP3 is starving at some point in that cycle.

Now, even if the lift pump on a CP3 system only supplies fuel at atmospheric pressure at the CP3 inlet, there is still 10ish PSI of pressure at the pump by the time the flow through the filter, through the lines, across the bypass and through the line is taken into account.

Nobody talks about this pressure, but it it there. At higher flows there is more pressure drop. With a dirty filter there is more pressure drop. With a second filter there is more pressure drop.

That is why when people run a Holley Blue with the regulator cranked right up (spring "adjusted") the pump puts out 18 PSI (at or beyond it max pressure), but they only see 7 PSI at the injection pump. There are other pressure losses in the system.

Now with the VP44 it is probably a bit different. There is no internal feedpump and an orifice controls the flow through for lubrication and cooling purposes. So the more pressure you feed that pump, the better it is cooled and lubricated. And the more sure you are of the pumping chambers being filled.

(Remember my talk on air, where I said that the fuel going into the pumping chambers has to be under pressure so that the air stays in solution ? Well, the higher the supply pressure, the greater the chance of that being the case.)

 

This is post #2.

"The diesel tech (who is member on here) and I talked about it for a while. What is the point of the high psi???"

You should understand it now. We are spec'ing pumps that have more pressure capability than is needed. We do this so that we get a robust pump. Not a feeble pump. We are not using all that pressure capability. The regulator controls the system pressure to whatever we set it to. There are pressure losses in the system that people don't discuss and we want 15 PSI at the VP44 all the time, even at WOT. Given that, we need pumps that deliver 20-30 PSI. With the "robustness margin" it is good to spec a pump that is built to deliver fuel at 60 -100 PSI. Then there is NO chance that the pump will wear out prematurely from being overloaded. Unlike the case when you spec a pump that is rated for say 7 PSI.

"Also, keep in mind that the CP3 will only pump so much fuel, hence why there are guys out there modifing them to get more from them, so having a "traffic jam" of fuel, that the CP3 cannot use (being as pressure is measurement of restriction), is like I said...watering your lawn with a fire hose."

Watering your "lawn" with a fire hose is better than watering it with a straw, because if the lawn goes dry too many times, it costs about $1500 to plant it again.

There is nothing wrong with having more fuel at the inlet of the CP3 than it can use. That ensures that it isn't starving. Ever. But it can be overdone, I agree. On that note, I have no idea why people want to run 90 and 150 GPM pumps, especially with the regulator at the pump, because all it does is flow a bunch of fuel back to the fuel tank. It serves the injection pump no practical purpose.

With the regulator at the injection pump, or using the bypass, all the fuel is right there at the pump inlet. It is almost impossible for the pump to starve. At least in that instance the fuel is flowing past the pump rather than just going back to the tank.

"I look around, and it been said that the Blue is out of its range (the red is on the low side IMO), but yet I don't see them failing in the CTD in wide margins."

Well, there are a couple things at work here.

First of all, most of the Blues are being used with the stock pump. This lessens the load on both the pumps and they start to live a little bit better.

Secondly, people are happy with feeding VP44s at 11 PSI idle, 6-7 PSI WOT. If you bump the supply spec up to 15 PSI WOT and move the regulator to the injection pump, suddenly the supply pump needs 20+ PSI and even double pumping ain't going to cut it.

And then there is the law of averages. And the law states that running a pump rated for 7 PSI at 20 PSI isn't going to last anywhere nearly as long as a pump rated for 80-100 PSI at 20 PSI.

Lets say you need to pull a 5,000 boat. Are you going to buy a 3.5L V6 or a Cummins turbo diesel ?

"The FASS is simple and a 1-stop shop, and with huge filters........that's its claim to fame. You pay the price of convienience.....period."

OK.

"There are a ton of pumps, carb or FI, out there on the market.....but the only one that works is the Walbro that has just been found??? "

Nope. Here is the criteria:
- flow rate greater than 40 GPM (Stock HP) and greater for mod'd engines
- rated for 60+ PSI. 40 is getting low. 50 probably OK.
- flow curve available
- cooled by fuel
- gerotor design
- designed for diesel fuel

I am advocating any pump that meets these criteria. Thus far we've uncovered the Walbro and the Bosch pump that strictly meet the criteria. Someone suggested a Toyota pump and I said it was worth a try.

I happen to think that in this class of pumps the Walbro is outstand because of its great robustness and its reasonable price. ($140).

I hope that clears things up.

Added in edit.

I keep harping on the motor when I say that the 80-100 PSI lift pumps will last longer than the carburetor lift pumps. But it isn't just the motor. For example, there are pictures on this board of the *plastic* bushing in a Carter failing and apparently it isn't an uncommon failure. OK. Do you think that a pump designed to pump fuel at 100 PSI is going to use a plastic bushing ? Probably not. At those pressures you need a metal bushing.

Another example: apparently the Carter pump has a built in pressure bypass. And over time it gets weaker and weaker until the pump no longer makes the rated pressure. Well, the Walbro and Bosch pumps have a built in bypass as well. Its purpose is to save the motor if you deadhead the pump. (hmmm.... like somone connecting it directly to a CP3.. who would do that ? ) The difference is that the pressure relief in the Walbro is at about 110 PSI, the Bosch at about 90 PSI and the Carter maybe 20 PSI ? So when the Carter is operated at its pressure limit, the bypass is constantly in operation and thus it gets weak and then the lift pump output falls and then... hmmm... your truck doesn't start right because the $1500 injection pump is "worn".

With the Walbro pressure relief at 110 PSI, it is NEVER in operation and it stays at 110 PSI.

So... when you buy a Walbro for $140 instead of a Carter for $180, you get rid of the plastic bushing and you get a 100 PSI relief instead of a 20 PSI relief. In addition to the motor improvements and the fact that the Walbro is a gerotor and...

Get the picture ?

The lift pump problems that Dodge Cummins trucks have experienced in the past are ENTIRELY preventable with the selection of the proper pump.

 

Trik, ya got it man. That is it in a nutshell. I hope this is making sense to other people too.

One more thing. Another reason to consider higher pressure pumps is when one adds another filter to the system.

The next improvement I will be implementing is the addition of a Cat 2 micron filter between the stock fuel filter and my CP3. Adding this filter or one like it will add more backpressure, further increasing the lift pumps load. With a Walbro (or equivalent) it isn't a problem. With a carburetor type pump it might be the straw that breaks the camels back.

 

I was thinking it might be worthwhile to add a coarse filter inline before the new lift pump, to keep the crud out of it.

Or what about this idea, move the factory filter to before the new lift pump (or bypass it altogether in favor of a similar filter), close to the tank. That way, you don't need to worry about pressures in the factory filter blowing it apart and your pump is only seeing filtered fuel to extend it's own life also.

Anyone got any pics or part numbers for the parts that Dodge uses when retorfitting the canister mounted lift pumps to in-tank? There must be an adapter plate or some special fuel line.

 

This is an implementation question. Care to move it to the implementation thread ? Can we keep this thread for discussing the merits and drawbacks of various fuel pumps ?

 

I wouldnt put the pump after the filter. Your filter should be the last thing the fuel sees before it goes to the IP.

 

Also, I understand that putting restrictions on the
suction side of a pump is usually discouraged.
Bad things can happen to the rotor/impeller/whatever.


Thanks for this and the other thead, and the ideas in
general. It's beginning to make sense to me, which
might be an indicator that you're pretty screwed up.


Lowell

 

"Bad things can happen to the rotor/impeller/whatever."

That is cavitation. I've never seen a small pump like a fuel pump cavitated, but it could happen. Generally the pump performance is really bad before it comes to that and people don't run it that way.

Cavitation is when the static pressure on the liquid is low and it vaporizes forming bubbles in the fluid. Then, when it is re pressurized the bubbles break with great energy, enough to be abrasive on parts.

For people that want to read about suction side concerns, I commented in the Implementing a Walbro thread at about post 40.

https://www.dieseltruckresource.com/...552#post864552


This post
http://dieselram.com/cgi-bin/ultimat...=005200#000013

Says: "The FASS PSI rating is 14-16 PSI, FASS II is 18-22 PSI."

Dunno if that is a continuous rating or a maximum rating, but they are way less than the continuous rating of the Bosch, Toyota and Walbro pumps we have been discussing.

22 PSI is **just** enough pressure to implement a system with the regulator at the injection pump. 15 PSI at the injection pump and 7 PSI for pressure drop across the filter and lines, worst case.

A guy in that post stated that heavily modded engines needed the 150 GPH FASS. I disagreed.

 

I found another pump that might work... the pump from a Dodge gasser truck of the same year.

The Dodge gasser pump outputs 60 PSI to the fuel rail on the gas models, so it is decently stout.

http://www.trademotion.com/partloca...&year=2005&cata logid=1

$173. I have no idea if it will stand up to diesel fuel.

Gasoline part number (of several) 5104696ab

This is probably a gerotor pump with no built in pressure relief.

You would have to run a bypass and/or a pressure relief at the injection pump to use this.