Need some "schooling" on pumps & fuel systems.

[DaveMorris]

Ok guys lets talk about the fuel systems on the new 3G's. I have 04' HO auto, an Edge EZ (everything else is stock) and recently set it on level 4. The truck takes off harder from a stop, but seems like it doesn't have "it" past mid and upper range (seems like less mid/high power than on the previous level 3). I am suspecting that I might be loosing fuel pressure, but don't know since I don't have a FP gauge on it right now. I have heard rumors that the stock system is barely acceptable for stock HP, and questionable with a pressure box.



I don't really plan on going any bigger HP for a long time, but just want to make the most from what I have now.



So if I am loosing pressure, what is the best way to fix this problem? Keep in mind that I do not want to make any perminant changes that can't be undone if I have to make a dealer visit. I don't mind making new fuel lines, etc. I will just keep my stock ones stored away for the dealer visits.



Please tell me what fuel component/s should be upgraded and give me some names on where to locate the products. Also please describe to me what the part does. . I hear alot about lift pumps, pusher pumps (what do they do, where are they located on the truck at). I know the fuel systems on gassers, but this diesel is a new ball game with parts that I am not familiar with.



A very simple break down of the fuel system would also be great.



Example like:

(F. I. Gasser)= tank>fuel pump>pressure regulator>injectors.





thank in advance,

Dave

 

[barbwire]

I am interested as well

Waiting

 

[rbattelle]

Your fuel system has 5 primary components:



1. Fuel tank (obvious)

2. Lift pump. This sucks fuel out of the tank and pumps it through the filter canister at relatively low pressure (5-15 psi), then on to the injector pump (see #3). The lift pump is mounted on the fuel filter cansiter, on the side closest to the firewall.

3. Injector pump. On the 3g-and-later trucks this is a CP-3 designator. It's only job in life is to provide pressure to the fuel rail (see #4) at 5000-25000 psi.

4. Fuel rail. This is the "log" looking think mounted parallel to the engine on the driver's side of the truck. It includes a pressure transducer, overpressure relief valve, and 6 fuel lines (one per injector).

5. Injectors. These use an electronically-actuated needle to provide fuel to their respective cylinder.



This entire system is made by Bosch for Cummins. Currently, there are no CP-3 upgrades that I am aware of, and the stock system I've heard is good up to around 400 RWHP (I think Keith from DD has posted to that effect). Beyond 400 RWHP, the injector pump is still okay, but you really need to upgrade the lift pump to something with a greater flow rate (and pressure) to keep from starving your injector pump. I will note that there is an ongoing debate over whether a CP-3 will fail from lack of lubrication if the lift pump can't keep up with fuel demand. Unless your lift pump was bad from the factory, you are not likely to be losing that much pressure due to the Edge.



The ECM controls the fuel pulse timing and duration, so there are 2 ways to boost power: increase rail pressure or increase pulse width (or both). Most fueling boxes, like Edge, increase rail pressure. I think timing boxes are just beginning to come on the market. If you search on "common rail" you'll find tons of good info as well.

 

[DaveMorris]

Great info thank you, I have read some of DD's post, but what concerns me is that some guys on this site have posted about pulling fuel pressure down to 0 with just the Edge (and a full throttle run). I know I am running into some kind of power weak link on my old gassers I would say it was a lean out problem, I am guessing it is the same trait for the diesel.



Speaking from my past we would piggy back a aux. fuel pump with the existing pump to come on when we hit boost or nitrous this pump would help the fuel system from starving out. Of course this was on gas engines.



Is something like this possible on a diesel (mounting a electronic pump at the tank)? Can you use a gas pump? does it have to be a diesel pump? What kind of flow rate and pressure would this need? I figure the pressure would be low, but flow would be high?



Thanks again,

Dave

 

[csutton7]

Dave--I think you're on the right track by either mounting an aux pump back by the tank to assist the OEM terribly located lift pump or better yet get another pump and crapcan the oem lift pump and mount the new pump as close to the tank as possible--let the electric pump do what it's supposed to do---push fuel not suck it 8' and then push it 18"---run the new relocated pump off of a relay that's triggered by the oem lift pump wire---maybe a prefilter(like stated before and a regulator if the pressure is to high)---increase line size(if upping HP) and rid yourself of the banjo bolts, by either getting the upgraded ones or going with AN fittings----basically all this is spelled out so many times in the 24valve forums it's not funny----I believe it's pretty much the same system except when you get to high pressure pump----chris

 

[HoleshotHolset]

Fuel pumps are usually not interchangable between gasoline and diesel... they're either one or the other.



I'm still surprised nobody is using Weldon pumps... they're expensive but VERY beefy... .



Matt

 

[barbwire]

Curious

Originally posted by HoleshotHolset

Fuel pumps are usually not interchangable between gasoline and diesel... they're either one or the other.



I'm still surprised nobody is using Weldon pumps... they're expensive but VERY beefy... .



Matt

Matt, I am curious as to why gas pumps will not work for diesel fuel. As, I took on off my old crane, and I thought about putting it on my 99. The old crane is a gasser. I thought fluid would be fluid, but I guess I need some insite. It is amazing as to how old you can be, and still be short on knowledge

Oh, yeah, where do you get info on those Weldon pumps?

 

[SRadke]

DD sells a "pusher pump kit" that consists of an electric pump mounted near the tank and larger line to run up to the stock filter housing. This sustem bypasses the stock lift pump compleetly. The alternative to this is something like a Fass system. Search on Fass and you'll come up with lots of reading. I don't know of a 3g specific Fass kit to date.



-Scott

 

[HoleshotHolset]

http://www.weldonracing.com/



Weldon has been making pumps for a LONG time - and started out making pumps for aerospace applications before they got into the race stuff. I have friends that swear by these pumps... . and feel that they're worth every penny.



Keep in mind that these pumps are NOT quiet in the least bit... . they're loud and proud and 100% rebuildable.



I don't have the specific part #'s for the diesel/jet fuel rated pumps they sell... . so you'd have to ask them.



Diesel eats right through stuff not rated for it... you gotta be carefuel (pun intended).



Matt

 

[barbwire]

Many thanks Matt

 

[HoleshotHolset]

No problem at all... .



Matt

 

[SLinse]

I'm pretty sure the FASS system will work on any truck. I helped with one on a 2000 powerstroke, and I was impressed!! It is a pusher pump, with a fuel filter, water seperator, AND it takes air out of the fuel. The guy said he noticed a big differance in towing, and I couldn't believe how much quieter it made that loud 7. 3! We dynoed it and it was looking like at least 10hp increase! I'm just not sure it is worth the $600 I think they are asking for it.