My lift pump/ CP3 feed solution
#31
"whats your take on the growing concern and "use" of finer filtering. Have you thought about adding in your setup??"
I've thought of it and I've even bought a filter.
The issue I had was finding a fine filter that was rated for some pressure. I found one: the Racor R120AS with the Racor R12S element. The S element is 2 micron. The 120 has a clear bowl on the bottom too.
I was going to install it between the stock filter and the CP3, where the rubber line splices the CP3 line to the fuel line. I haven't installed it due to time constraints.
I think it is good to 10PSI. One can't just use a 2 micron filter. You need to prefilter with something coarser. The stock filter should work fine for that.
The cost on the Racor 120AS is about $65 with an element. It is rated for lower flow, but works fine at high flows. The low flow rating is at 1 PSI pressure drop. Higher flows just have more pressure drop.
My engine runs so well I am not sure that the second filter is warranted. I read a lot before installing my engine and was worried about developing an engine knock. I'm not sure my engine would be under warranty. Thankfully, my engine runs excellent.
I've thought of it and I've even bought a filter.
The issue I had was finding a fine filter that was rated for some pressure. I found one: the Racor R120AS with the Racor R12S element. The S element is 2 micron. The 120 has a clear bowl on the bottom too.
I was going to install it between the stock filter and the CP3, where the rubber line splices the CP3 line to the fuel line. I haven't installed it due to time constraints.
I think it is good to 10PSI. One can't just use a 2 micron filter. You need to prefilter with something coarser. The stock filter should work fine for that.
The cost on the Racor 120AS is about $65 with an element. It is rated for lower flow, but works fine at high flows. The low flow rating is at 1 PSI pressure drop. Higher flows just have more pressure drop.
My engine runs so well I am not sure that the second filter is warranted. I read a lot before installing my engine and was worried about developing an engine knock. I'm not sure my engine would be under warranty. Thankfully, my engine runs excellent.
#32
For those of you that want to use a Walbro but want to keep the pump in the tank, I seem to recall that Walbro had a kit to mount the GSL392 in the tank or the pump was certified for in tank use or something like that. It has been a long time since I looked at the 392.
I am not sure that the "air separation" and extra filtering some of the other pump systems offer are really necessary.
I am not sure that the "air separation" and extra filtering some of the other pump systems offer are really necessary.
#33
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It's all good info., and since mine is still in warranty, I think I might just install a pressure gauge somewhere between the water,fuelfilter can, and the CP3, that way if the supply line pressure drops, it's either a plugged filter, or a bad intank pump.This way I can monitor my fuel system, and it won't cost much.One question, how much pressure do you think is at the CP3 inlet, so I know what size guage to buy.
#34
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more than zero but less than 15...auto meter make a 0-30 electric that fits the bill...also if you do a search on fuel pressure you will get lots of recomendations for what the pressur should be at different throttle positions...
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superduty I just reread the post..I am going to be doing this in some for or another since alot of the newer pumps seems to be developing leaks on a seal due to inadequate fueling. what did u use to regulate the pressure? if you are allowing 60psi at the pump the bypass is enough to keep from over pressuring your pump..?
#36
"what did u use to regulate the pressure? if you are allowing 60psi at the pump the bypass is enough to keep from over pressuring your pump..?"
Nothing regulates the pressure. The lift pump just circulates clean fuel and lots of it right past the CP3 inlet, through the bypass line and back to the tank. The CP3 takes as much or little as it needs.
Nothing regulates the pressure. The lift pump just circulates clean fuel and lots of it right past the CP3 inlet, through the bypass line and back to the tank. The CP3 takes as much or little as it needs.
#38
I bought the Walbro back in 2001. I don't remember what I paid for it or even where I bought it. I can't find the receipt.
Production ? There isn't anything to produce other than the banjo bolts. You guys should be able to find a machine shop to drill and thread a hundred or so of those. I thought Genos was selling them for people to put pressure gauges on their trucks ? 1/8" NPT.
The Walbros come with a mounting kit. Just bolt it to the frame rail and wire it up. Cut the pressure line from the tank and splice in the Walbro. You guys with pumps in the tank will have to drop your tank and pull the pump. Yuck, I know, but not killer.
The whole parts list would be:
1 Walbro
2 drilled and tapped Banjo bolts
2 3/16" x 1/8" NPT hose barbs
1 piece of hose for the bypass (3/16")
2 1/8 NPT x 1/4" nose barbs
2 short pieces of 1/4" hose for the splice
Hose clamps
Little bit of wire and connectors.
The guys with in tank pumps will need to rig up a tank pickup system. I'd look at the pickups used in the 03.5s to see how they did it. (03.5s have the fuel pump mounted on the engine, right ? Bad place btw: heat and vibration. What were they thinking ?) Making a fuel pickup out of a tank with an in tank pump might be as easy as removing the pump and replacing it with a piece of hose.
You might also do a Duramax and try running without a lift pump at all. I dunno much about how they do it, but filter cleanliness is paramount doing something like that.
I think the Walbro can mount right in the tank if it was wanted as such.
Just in case someone missed it, I did a post about the CP3 being rebuildable. If I ever blow a CP3, I'll be rebuilding it myself. It isn't rocket science.
BTW: A CP3 is WAY simpler than a VP44. All the CP3 does is pump fuel. No metering other than pressure control. No timing. No distributor plate in it. No govenor. No computer. No high speed valves. Just 3 plungers going back and forth on a cam. It is the simplest fuel pump of any of the Cummins engines VE, P7100 or VP44. That is why I keep saying that it is a crying shame to be having these problems.
Feed it lots of clean fuel and it will last forever. Just like the engine itself.
Production ? There isn't anything to produce other than the banjo bolts. You guys should be able to find a machine shop to drill and thread a hundred or so of those. I thought Genos was selling them for people to put pressure gauges on their trucks ? 1/8" NPT.
The Walbros come with a mounting kit. Just bolt it to the frame rail and wire it up. Cut the pressure line from the tank and splice in the Walbro. You guys with pumps in the tank will have to drop your tank and pull the pump. Yuck, I know, but not killer.
The whole parts list would be:
1 Walbro
2 drilled and tapped Banjo bolts
2 3/16" x 1/8" NPT hose barbs
1 piece of hose for the bypass (3/16")
2 1/8 NPT x 1/4" nose barbs
2 short pieces of 1/4" hose for the splice
Hose clamps
Little bit of wire and connectors.
The guys with in tank pumps will need to rig up a tank pickup system. I'd look at the pickups used in the 03.5s to see how they did it. (03.5s have the fuel pump mounted on the engine, right ? Bad place btw: heat and vibration. What were they thinking ?) Making a fuel pickup out of a tank with an in tank pump might be as easy as removing the pump and replacing it with a piece of hose.
You might also do a Duramax and try running without a lift pump at all. I dunno much about how they do it, but filter cleanliness is paramount doing something like that.
I think the Walbro can mount right in the tank if it was wanted as such.
Just in case someone missed it, I did a post about the CP3 being rebuildable. If I ever blow a CP3, I'll be rebuilding it myself. It isn't rocket science.
BTW: A CP3 is WAY simpler than a VP44. All the CP3 does is pump fuel. No metering other than pressure control. No timing. No distributor plate in it. No govenor. No computer. No high speed valves. Just 3 plungers going back and forth on a cam. It is the simplest fuel pump of any of the Cummins engines VE, P7100 or VP44. That is why I keep saying that it is a crying shame to be having these problems.
Feed it lots of clean fuel and it will last forever. Just like the engine itself.
#39
OK, let me get this straight (once again, cut me some slack since I am coming from a Ford PSD ) You have the fuel tank with the sending unit and pick up in the tank, an external pump (the LP) that pulls fuel from the tank and supplies fuel to another pump at the front of the motor. The LP will fail, which no longer delivers fuel to the pump at the motor, and then that pump since there is not an adequate amount of fuel to cool it down, will fail also. I am just trying to figure out the basics of the fuel system on our trucks, and some other things so i can be prepared. If I have that all wrong, plese feel free to correct me. Or, if I am close let me knwo what I missed. Also, what fuel pressure are thepumps running at. I have read the thread and seems the LP is a low pressure pump, correct, and some guys are replacing with the holley blue pump?
Also, what is the FASS pump??????
Also, what is the FASS pump??????
#40
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Walbro 392
Seen the Walbro pumps on E-Bay for $120.00 buy it now price. Now if someone wants to produce the banjo bolts for the rest of us without the proper tools, it seems like a fairly straightforward conversion. I think the wiring harness setup could be easily made to plug into the canister mounted plug. Any ideas? Oh yeah anyone who has an 05 with the canister blanked off could you please post a picture. Thanks and Merry Christmas!
#41
"OK, let me get this straight (once again, cut me some slack since I am coming from a Ford PSD )"
me too... join the club...
"You have the fuel tank with the sending unit and pick up in the tank, an external pump (the LP) that pulls fuel from the tank and supplies fuel to another pump at the front of the motor."
Not quite... the Dodges only have one lift pump. I think the 03.5s had the lift pump mounted on the engine by the filter assembly and then they changed the pump location to be in the tank. So you'll either have a LP near the filter assembly or in the tank on a stock truck.
"The LP will fail"
They seem to with pretty good regularity, yes.
"which no longer delivers fuel to the pump at the motor, and then that pump since there is not an adequate amount of fuel to cool it down, will fail also."
OK, I see what you meant about the other pump now... The high pressure pump on the engine is called a CP3. It is a mechanically driven pump with 3 plungers and barrels. It drives off the front gear drive on the engine. It provides the high pressure fuel (3500-28,000 PSI) for the injectors. It pumps into the fuel rail on the side of the engine.
The CP3 needs enough fuel to feed the engine plus an excess that circulates through it and back into the return line. The purpose of the excess fuel is to lubricate and cool the pump. No excess fuel flow = pump damage.
"I am just trying to figure out the basics of the fuel system on our trucks, and some other things so i can be prepared. If I have that all wrong, plese feel free to correct me."
You got it. No such thing as a dumb question, so keep asking.
"Also, what fuel pressure are thepumps running at."
I think the stock lift pumps are providing fuel at a few to five ish PSI at the CP3 under idle conditions. I think that pressure drops to nothing at WOT or with a dirty filter. I don't have a Dodge or a fuel pressure gauge for that matter so I am not the best to answer.
The CP3 runs at injection pressures, 3500 to 28,000 ish PSI.
"I have read the thread and seems the LP is a low pressure pump, correct"
Yes.
"and some guys are replacing with the holley blue pump?"
Be careful with that. I helped a guy troubleshoot a fuel supply problem back in Oct (?) and the problem was a holley blue pump.
"Also, what is the FASS pump??????"
http://www.atsdiesel.com/ATSWebsite/...Dodge/Fuel.asp
There is great debate about "air in the fuel", extra filtering, fuel gelling with extra (unheated) filters, especially fine ones.
Ford owners seem to think they have air in the fuel and that it causes cackle on the 7.3s. However, my Cummins purrs like a kitten with the stock 7.3 fuel delivery system. (Walbro in place of Bosch though.)
I like all the fuel going past the CP3 and none going to the tank before then. This makes sure that all of the LPs power goes to pushing fuel through the stock filter. The FASS and other systems use a relief valve that circulates the fuel back to the tank prior to the stock filter. And the relief valve is preset at a nominal pressure like 10-20 PSI. So you get 10-20 PSI pushing fuel through the stock filter to the CP3. The pump always operates at 10-20 PSI backpressure. As the stock filter becomes dirty less and less fuel flow makes it to the CP3. If the stock filter plugs the CP3 starves.
Pump systems using a pressure relief prior to the stock filter are essentially feeding the stock filter with a constant pressure source. How much fuel actually makes it to the CP3 depends on the shape of the the stock filter.
With the bypass system all the pump flow goes to the CP3. There is no relief circuit back to the tank. When the filter is clean the back pressure on the pump is a few PSI. As the filter plugs the pump flow drops due to pump loading, but the Walbro is more than up to the task of feeding the CP3.
The Walbro is a strong pump. It will push 60 PSI for years (as it does in the Powerstroke and gas fuel injection applications) for years. The Holley blue pump is designed to feel a carburetor, which needs a few PSI max. Two totally different fuel pump designs.
me too... join the club...
"You have the fuel tank with the sending unit and pick up in the tank, an external pump (the LP) that pulls fuel from the tank and supplies fuel to another pump at the front of the motor."
Not quite... the Dodges only have one lift pump. I think the 03.5s had the lift pump mounted on the engine by the filter assembly and then they changed the pump location to be in the tank. So you'll either have a LP near the filter assembly or in the tank on a stock truck.
"The LP will fail"
They seem to with pretty good regularity, yes.
"which no longer delivers fuel to the pump at the motor, and then that pump since there is not an adequate amount of fuel to cool it down, will fail also."
OK, I see what you meant about the other pump now... The high pressure pump on the engine is called a CP3. It is a mechanically driven pump with 3 plungers and barrels. It drives off the front gear drive on the engine. It provides the high pressure fuel (3500-28,000 PSI) for the injectors. It pumps into the fuel rail on the side of the engine.
The CP3 needs enough fuel to feed the engine plus an excess that circulates through it and back into the return line. The purpose of the excess fuel is to lubricate and cool the pump. No excess fuel flow = pump damage.
"I am just trying to figure out the basics of the fuel system on our trucks, and some other things so i can be prepared. If I have that all wrong, plese feel free to correct me."
You got it. No such thing as a dumb question, so keep asking.
"Also, what fuel pressure are thepumps running at."
I think the stock lift pumps are providing fuel at a few to five ish PSI at the CP3 under idle conditions. I think that pressure drops to nothing at WOT or with a dirty filter. I don't have a Dodge or a fuel pressure gauge for that matter so I am not the best to answer.
The CP3 runs at injection pressures, 3500 to 28,000 ish PSI.
"I have read the thread and seems the LP is a low pressure pump, correct"
Yes.
"and some guys are replacing with the holley blue pump?"
Be careful with that. I helped a guy troubleshoot a fuel supply problem back in Oct (?) and the problem was a holley blue pump.
"Also, what is the FASS pump??????"
http://www.atsdiesel.com/ATSWebsite/...Dodge/Fuel.asp
There is great debate about "air in the fuel", extra filtering, fuel gelling with extra (unheated) filters, especially fine ones.
Ford owners seem to think they have air in the fuel and that it causes cackle on the 7.3s. However, my Cummins purrs like a kitten with the stock 7.3 fuel delivery system. (Walbro in place of Bosch though.)
I like all the fuel going past the CP3 and none going to the tank before then. This makes sure that all of the LPs power goes to pushing fuel through the stock filter. The FASS and other systems use a relief valve that circulates the fuel back to the tank prior to the stock filter. And the relief valve is preset at a nominal pressure like 10-20 PSI. So you get 10-20 PSI pushing fuel through the stock filter to the CP3. The pump always operates at 10-20 PSI backpressure. As the stock filter becomes dirty less and less fuel flow makes it to the CP3. If the stock filter plugs the CP3 starves.
Pump systems using a pressure relief prior to the stock filter are essentially feeding the stock filter with a constant pressure source. How much fuel actually makes it to the CP3 depends on the shape of the the stock filter.
With the bypass system all the pump flow goes to the CP3. There is no relief circuit back to the tank. When the filter is clean the back pressure on the pump is a few PSI. As the filter plugs the pump flow drops due to pump loading, but the Walbro is more than up to the task of feeding the CP3.
The Walbro is a strong pump. It will push 60 PSI for years (as it does in the Powerstroke and gas fuel injection applications) for years. The Holley blue pump is designed to feel a carburetor, which needs a few PSI max. Two totally different fuel pump designs.
#42
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#43
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Forgive me if I missed it but have you monitored what PSI you are actually running with the bypass sized the way it is now? Does it actually restrict enough to make a bit of pressure?
#44
"Forgive me if I missed it but have you monitored what PSI you are actually running with the bypass sized the way it is now? Does it actually restrict enough to make a bit of pressure?"
No, I haven't. I specifically chose the bypass line to be a bit small (3/16") to create a bit of backpressure, plus there is the backpressure of the return line which is also submerged in fuel in the tank. And the 392 is pumping at 50 gallons per hour.
Remember the CP3 doesn't need ANY pressure in its feed. It has a built in supply pump that is capable of SUCKING fuel from the tank all by itself, like it does in the Duramax application. Duramaxes, at least the first ones, didn't have a lift pump at all. The CP3 sucked fuel right from the tank through a filter. No lift pump at all. I'm sure this was the best setup, but there certainly isn't a need to provide the CP3 with much pressure.
Glad to see you found a 392 link with flow charts. Good work.
325HP x BSFC of 0.390 = 126 pounds per hour. Diesel weighs 7 pounds per gallon so that is 18 gallons per hour. The Walbro will do 50 GPH at 60PSI, so there is way more pump there than is needed.
BTW: I am not sure how much current the ECM will supply for the pump. My 05 ECM drives a fuel pump relay as I think it does on all the Dodges. I think the other trucks will as well. You might have to check the relay capacity and fuse size.
There are smaller pumps that might work just as well. The 392 is one hell of a pump.
Note that there is a in tank pickup kit available for those that want to mount in the tank.
No, I haven't. I specifically chose the bypass line to be a bit small (3/16") to create a bit of backpressure, plus there is the backpressure of the return line which is also submerged in fuel in the tank. And the 392 is pumping at 50 gallons per hour.
Remember the CP3 doesn't need ANY pressure in its feed. It has a built in supply pump that is capable of SUCKING fuel from the tank all by itself, like it does in the Duramax application. Duramaxes, at least the first ones, didn't have a lift pump at all. The CP3 sucked fuel right from the tank through a filter. No lift pump at all. I'm sure this was the best setup, but there certainly isn't a need to provide the CP3 with much pressure.
Glad to see you found a 392 link with flow charts. Good work.
325HP x BSFC of 0.390 = 126 pounds per hour. Diesel weighs 7 pounds per gallon so that is 18 gallons per hour. The Walbro will do 50 GPH at 60PSI, so there is way more pump there than is needed.
BTW: I am not sure how much current the ECM will supply for the pump. My 05 ECM drives a fuel pump relay as I think it does on all the Dodges. I think the other trucks will as well. You might have to check the relay capacity and fuse size.
There are smaller pumps that might work just as well. The 392 is one hell of a pump.
Note that there is a in tank pickup kit available for those that want to mount in the tank.
#45
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Cool, I think I am going to do it. I wish I had spare Banjo's in case I mess one up. Do you know what size they are? I think it might be nice to have a pressure gauge in there somewhere too.