Fuel system question

Diesel God said:

I was readin over on that other thread about the fuel filters. Seems like some of you fellas know what you're talkin about, some of you just try to repeat what you read on some other site. Weren't doin too good of a job of it at that.


This question is for you smart fellas. I been readin over on TDR (lotta smart fellas over there) and it looks like Cummins has decided to change over to the same Bosch fuel system that the Durmax has, they call it HPCR.


So why are they using a lift pump to feed the fatory pump. Seems to me they wouldn't spend the money on somethin like that unless they found some need for it?


Ain't lookin for an argument, so if you got nothin' intelligent to say, keep yer yap shut. I'd like to here from somebuddy with personal experince or a cluye wha they'e talkin about.


Ideas?

Click to expand...

Good Mourning .....


This has been hashed out considerable lately ..... Our system is also a High Pressure Common Rail Bosch system ..... Likely difference in the two are different Injectors and D/C has installed a better finer 2um but not absolute, Fuel filter ....

If anyone can contribute to WHY Cummins added a lift pump, I'll let this fly .... If it turns into a debate on fuel filters it'll be gone before you can say "Happy Birthday " .....

Mac Edited by: Mackin

Diesel God said:

I'd like to here from somebuddy with personal experince or a cluye wha they'e talkin about.


Ideas?

Click to expand...

Well apparently you were unable to get this question answered anywhere else which means this site is worth something to you. I'll give it a shot.

BTW: We could do without the "smart" comments in light of the context of the post.

Here goes......

One GUESS is Dodge is a different truck than the GM. That means even though they have similar injection systems, that does not mean the Dodge fuel system as a whole works exactly the same as the GM fuel system.

Remember, these are systems. They are designed to work as systems. All it takes is a different length line, different diameters, different fuel flow requirements etc. and your design might show the requirement for a lift pump.

OR....
Dodge decided a lift pump and a high quality fuel filter could reduce warranty claims due to premature injector/injector pump wear.

Does anybody here know that for sure. Maybe the best place to get an answer to that is over on TDR where all the Dodge experts are. Cost you about $35 to post it though and an answer isn't guaranteed.

We would like to see the long term results on all these different ideas that have been implemented. I think Bosch/Dodge may have had the benefit of learning from GM with respect to filtering fuel. After all, I'm sure Bosch provided fuel quality standards for the Dmax system when it was initially designed. I wonder if Bosch revised their filtering requirements because of the lessor grade of fuel available in the US. Or if filtering is the total answer. I'm sure they are also tweeking component designs to better handle dirty fuel, There's more than one way to skin the CAT. The newer injectors with some harder components in the Dmax is one example of that.

Either way, more answers will surface as new designs or changes are introduced with all these trucks.

It's the trucks that many of us own (first generation) that may not have the optimum fuel system setup that makes these forums such an asset. You don't get much info from the manufacturers on these subjects.

It's all good stuff and all part of the advance of technology in the diesel/automotive world.








Edited by: hoot

Diesel God said:

I was readin over on that other thread about the fuel filters. Seems like some of you fellas know what you're talkin about, some of you just try to repeat what you read on some other site. Weren't doin too good of a job of it at that.


This question is for you smart fellas. I been readin over on TDR (lotta smart fellas over there) and it looks like Cummins has decided to change over to the same Bosch fuel system that the Durmax has, they call it HPCR.


So why are they using a lift pump to feed the fatory pump. Seems to me they wouldn't spend the money on somethin like that unless they found some need for it?


Ain't lookin for an argument, so if you got nothin' intelligent to say, keep yer yap shut. I'd like to here from somebuddy with personal experince or a cluye wha they'e talkin about.


Ideas?

Click to expand...

Diesel God,


First off welcome to the forum.........


I would welcome any one that you may know of to share thier knowledge and info with us.


GMC

It appears a leading "expert" John Kennedy, already queried Bosch, the maker of our fuel pump and injector system, about using a lift pump with our system. Who would know better than Kennedy and Bosch?


On 4/22/03, Kennedy stated:


"Bosch's stand is that it is not necessary, nor recommended."


..."The old 6.5 lift pump may well work just fine, but proceed at your own risk."


The context of the question and answer was in a discussion of a means to eliminate stalling and no starts using a post-oem filter.

IS IT JUST ME OR IS THERE SOME UNDERLYING REASON EVERYONE SO ON EDGE HERE(NO PUN INTENDED) I think the question is a valueable one. Did GM provide us with a marginal fuel filtering and the abscence of a lift pump to save a few dolllars or did dodge just learn from GM's mistake and build on and create a better system ?.........the addition of a lift pump in my mind is a good thing if it enables you to push fuel thru a finer filter without air or a restriction.........whats another $250 in the big picture


vincent

It's not that we are on edge. Mr. X just keeps driving it like a friggin horny dog looking for a mate

It's when the stuff keeps getting repeated over and over that gets old. Not on edge at all AT ALL NOT AT ALL


On edit,

Afte Mr. X just posted.... he does make a valid point that adding something like a lift pump adds other considerations. I think that's why GM attempted to stay away from it in the first place. Less parts, cheaper, lighter, more powerful than a locomotive, able toolwilkrewevoliqoEdited by: hoot

Repeat? What's been repeated?


Don't you think that those who want to get a lift pump should get one that still allows fuel to flow if it malfunctions?


Like I've been asking everyone since the beginning, if you have a problem with any of my statements of fact, then please, for the benefit of all, correct me!


Otherwise, in lieu of anything factual to state about the topic, why encourage members to waste bandwidth and foul up a thread with this personal crap?


I have never made a personally abusive statement against anyone. I have conveyed a lot of useful information to this site in a small period of time - all the time asking for corrections and correcting my infor as new info surfaces.


Why are you targeting me with this personal BS?

Mr X wrote


like I've been asking everyone since the beginning, if you have a problem with any of my statements of fact, then please, for the benefit of all, correct me!





Please Mr X I really respect your-your expert opinion. I'm so glad we have you to keep us straight with all these facts. Would you please please give me the details on how my Bosch pump will self destruct if my lift pump fails. Will it-it be like a bomb or something. I really wouldn't want to get my wittle self hurt. I did pull the fuse on my lift pump and measure the vac at idle and WOT and it did seem kinda OK. Have I been sitting on a time BOMB for 18000 miles.


Thanks in advance for your expert obsession - I mean opinion

a bear,


1st, I never claimed to be an expert at all. Just passing along Kennedy's very own words that he quoted from Bosch.


Here's some more from Kennedy on this subject, 4/21/03:
Word is, that the VP44 pump on the Cummins runs throughout Europe w/o a lift pump, and have a VERY low failure rate. US applications have added lift pumps, and have MUCH higher pump failure rates. This is partially due to failiure of the lift pumps causing severe restriction on the injection pump.


Just what I was told...


Tructh is, there really isn't much out there that can pump diesel continuously AND reliably along with allowing a "pull through" design so as to allow normal operation in the event of failure...


I understand that the Cummins lift pump does not allolw by-pass/flow thru in case of a faulure. Therefore, the injection pump (VP44) goes dry and it kills it. We have the VP44.


BTW, isn't Kennedy the one that sold you that lift pump after your Mega filter kept causing you to stall? Funny he would go against the Bosch recommendation.


I assume you must have a lift pump with a by-pass that still allows fuel flow if it malfunctions. Is a an AC Delco? Aren't they rated for about 60,000 miles? Don't you need still another filter to protect the AC Delco lift pump?


How do you have it wired? Need a relay? Did you wire it to an oil pressure switch so in case of an accident, it will turn off, and not continue pumping diesel all over the scene?


Seems like a lot of extra trouble just to make a filter work; especiallyh since the experts have concluded ther's no problem with "outgassing" and cavitation. A Bear, weren't you the one that first invented the word "out gassing?"


My only recommendation was to make sure that if a lift pump were used, it had a by-pass in case of lift pump failure.


Are you saying that that is bad advice?


What exactly do you not agree with. Or are you just another TDP person coming over here with a chip on your shoulder?

You want to know. It's your continually harping against certain filters, using a lift pump and anything else you seem to feel you know more about than people that have actually done something like TESTING.


It's your continually trying to sound impressive by using data that you dig up and post like it is gospil even when it has nothing to do with the post or is wrong.


It's your continual crying about being attacked when your just as guilty of attacking.


Why did you have to come here under a new name?? Maybe because no one wanted to play nice with you anymore?? Didn't last long here either did it?


It's not censorship MR X. it's trying to keep topics moving ahead with real information and not info that is made up or quoted out of context to make it fit your point.


You asked, I told you.

To answer your questions.


Did Kennedy sell you that lift pump after you had a stall? Nope and also no stall.


Is a an AC Delco? Yep


Aren't they rated for about 60,000 miles? Dunno/Don't care


Don't you need still another filter to protect the AC Delco lift pump? Nope


How do you have it wired? Ignition


Need a relay? Nahhhh


Did you wire it to an oil pressure switch so in case of an accident, it will turn off, and not continue pumping diesel all over the scene? Yep, but soon to change.


Seems like a lot of extra trouble just to make a filter work; especiallyh since the experts have concluded ther's no problem with "outgassing" and cavitation. Did someone say there is no outgassing. Hmmmm, How did they verify this? This is simple physics. Maybe you should ask the ones who got their hands dirty researching this. Maybe I should not be dealing with 60,000 barrels of oil a day that contains about 6mmcfd flash gas (6 million cubic feet) which is calculated and measured to API standards at many different stages based pressure drops and temps among others.


A Bear, weren't you the one that first invented the word "out gassing?" Nope, but I used the statement to stay on the same page with others. Never heard of the word before I got here. Feel free to check. I know its one of your specialties.


What exactly do you not agree with. Or are you just another TDP person coming over here with a chip on your shoulder? I think everyone here knows what I disagree with. I think many others share that feeling. No chip, nor am I trying to push a lift pump. I think everyone is very capable of making their own informed desision for their setup.


Frankly I will no longer respond to your experties. Conflict is no way to start a forum unless it is constructive. Just thought I would set the record straight on your questions.

a bear,


On 8/15/03, I asked you if you could keep running with a Mega filter if your lift pump quit. Below is your response.


Your words/not mine!


As far as the lift pump goes It WILL NOT leave you stranded. Just ride as normal untill you change the pump. Who cares if you have to bleed once in a tank of fuel only in the summer while finding the time to change it out.


I gathered from the below Kennedy post of 5/19/03, that you bought it from him. I guess he gave it to you?


I have Abear running a small lift pump. From what I am told, the transfer side of the Bosch pump is a vane type pump, and there is no apparent "weakness" or area that would be built for vacuum and succumb to psi. We'll see how Tommy does. Initial findingsare that the lift pump when stalled (not running) will increase restriction by about 2"hg. This isn't really all that bad considering that there is a 1" difference from E to F on the tank level.


Insofar as "outgassing" not being a problem... The experts have weighed in saying that air/vapor bubbles are not the same as cavitation and do not cause the same damage as cavitation.


DuramaxAlliTech even joked about it.


If you want to talk about outgassing, lets meet at the local Mexican resturaunt and have some wet burritos. I think we will have properly defined it and know quite a bit about it at the end of the night. Cavitation? fancy term used by me dentist cause I eat too much sugar and drink too much Coke...I dont know who said it, but if it was an issue, dont you think Bosch would have done something by now?


I do not claim expertise. Just total independence from any vendor's influence whatsoever.


I don't get Kennedy freebies for my truck.

abear ..........right on track bzzzzzzzzzzzzzzzzzz


I still think the lift pump/filter has great merit and given time GM will to. The cost of of the assembly at the manafacturers level has to be less than the cost of replacing one injector over the life of the vehicle. I would like to know actually how clean a new dodges filter cleans fuel.........any help from dodge guys reading would be appreciated.........if you are not a member yet I would avoid the letters H,B,X AND Y VINNIE