1/2 vulcan draw straw 3

[Silverdodge]

15 minutes ago, dripley said:

You can fill it up and see if it changes. That would eliminate fuel slosh being the culprit.

 

17 years of pulling fuel from basket with no issues or leaks and it still will drain the tank. Never saw a need for a sump. But I am still a firm believer in "to each his own".

Same with the to each there own previous owner of my truck installed a draw straw and did it wrong so had quarter tank issues so I said I'm done sumped it fixed everything

[01cummins4ever]

37 minutes ago, JAG1 said:

Since you have good fuel pressure when you first start it up, then later it goes low at idle after a run it sounds like symptoms of a clogged tank vent. That will create a vacuum in the tank at idle that it cannot overcome like when running higher RPMs.

 

Go for a run with the fuel cap off and see if any difference.

I will have to give that a try, I’m defently loosing the pressure on deceleration and holds good pressure at higher rpm, as long as I can keep it above 2k rpm it won’t drop below 17 psi, any engine speed below 2k the fuel pressure drops With the rpm, sometimes it will go down to about 2psi, and won’t recover until I get on it hard

[dripley]

1 minute ago, 01cummins4ever said:

I will have to give that a try, I’m defently loosing the pressure on deceleration and holds good pressure at higher rpm, as long as I can keep it above 2k rpm it won’t drop below 17 psi, any engine speed below 2k the fuel pressure drops With the rpm, sometimes it will go down to about 2psi, and won’t recover until I get on it hard

That definitely does NOT sound like fuel slosh and random air bubbles.

[Silverdodge]

29 minutes ago, dripley said:

 

Sounds to me like there's something wrong with the fuel boss itself

[JAG1]

If running with the cap off doesn't make a difference try helping the regulator break in a little (assuming it's a new regulator) by turning it up to about 27 and back down to around 6 at idle. Do that several times. This helped both my new Raptor pump regulators when new and were acting up. This was suggested by none other than Mopar1973Man after doing everything possible to stop the erratic pressure readings that drove me bananas on both my 2nd gens..

Edited March 17, 2019 by JAG1

[Mopar1973Man]

No issue here. No sump. Old school straw. 300k miles still trucking. I've even been down to the empty mark.

.

Not many can do what I have. Most screw up the tip with cuts or notches.

[01cummins4ever]

11 hours ago, JAG1 said:

If running with the cap off doesn't make a difference try helping the regulator break in a little (assuming it's a new regulator) by turning it up to about 27 and back down to around 6 at idle. Do that several times. This helped both my new Raptor pump regulators when new and were acting up. This was suggested by none other than Mopar1973Man after doing everything possible to stop the erratic pressure readings that drove me bananas on both my 2nd gens..

I tried running with the fuel cap off, drove about 10 miles, everything was fine then slowed down and thier goes the fuel pressure down to about 4,

 

I do not have an electric pump with the adjustable regulator, I have the mechanical fuel boss. which I believe is doing it’s job, the fuel is regulated with a brass bypass valve with a spring loaded piston inside which is located on the return fuel going to the tank, (this is in addition to the factory return comming from engine going back to the fuel basket) it’s supposed to stay closed until 17psi then open up and let excess fuel return to the tank as the fuel pressure increases due to acceleration and engine rpm, that’s the way the fuel boss is designed. So that being said I am leaning toward the bypass  valve sticking or not sealing when the fuel gets warm. I took the valve apart and inspected it and there was absolutely no debris or any  other matter inside so maybe it’s sticking open when fuel gets warm. When the psi dropped to below 10 I pulled over and crawled under truck and tapped on the valve with a screwdriver and bam, My fuel pressure spikes right back to 17psi. I guess I will have to contact Glasier Diesel Power in the morning and see if this valve can be fixed or just replace. 

7 hours ago, Mopar1973Man said:

No issue here. No sump. Old school straw. 300k miles still trucking. I've even been down to the empty mark.

.

Not many can do what I have. Most screw up the tip with cuts or notches.

I have the straw installed stand alone out side the basket It’s cut about 1/8” from bottom of empty tank with two notches just to aid in fuel volume suction 

[Mopar1973Man]

Too wide of gap...(possibly) Lay a quarter (coin) on the bottom that what you measure too on an empty tank. No real notches needed I very lightly notch mine, not for volume but to prevent it from sucking flat to the bottom. The design is to let the deflection of the tank bottom rise up to the tip of the straw close to allow it to suck up as much fuel as possible. The bottom deflects another 3/16 or so with the full tank. So cutting the straw short causes the 1/4 tank issue.

[mountaindan]

What kind of pressure gauge do you have?  I had trouble with my electric gauge,. Went to manual one and now hold a steady puesure both at idle and WOT

[01cummins4ever]

19 minutes ago, mountaindan said:

What kind of pressure gauge do you have?  I had trouble with my electric gauge,. Went to manual one and now hold a steady puesure both at idle and WOT

Electric isspro ev series, I know the mechanical are more accurate but I don’t believe it’s the gauge at this time. But not sure of anything yet 

[Dieselfuture]

I'll have to say it's your pump or not enough tension on the belt. Maybe when you decelerate belt slips a little. Pressure shouldn't change still same RPM.

[dripley]

Get a test gauage aee what it confirms the pressure drop.

[JAG1]

2 hours ago, dripley said:

Get a test gauage aee what it confirms the pressure drop.

Since I have two second gens I installed schrader valves in the fuel lines and purchased a fuel pressure test gauge. It is supposed to be very accurate being that it is an industrial gauge with it's own air bleed button. 

 

I was surprised to find both mechanical gauges in the cab where showing less than actual pressure. One showing 4.5 lbs less than actual (was after removal of the isolator) and the other truck showed 1 lb less than actual.(no isolator). I was disappointed. They are both mechanical gauges, The more accurate is the standard Isspro which is a couple years old.

[CUMMINSDIESELPWR]

On 3/17/2019 at 2:30 PM, 01cummins4ever said:

I tried running with the fuel cap off, drove about 10 miles, everything was fine then slowed down and thier goes the fuel pressure down to about 4,

 

I do not have an electric pump with the adjustable regulator, I have the mechanical fuel boss. which I believe is doing it’s job, the fuel is regulated with a brass bypass valve with a spring loaded piston inside which is located on the return fuel going to the tank, (this is in addition to the factory return comming from engine going back to the fuel basket) it’s supposed to stay closed until 17psi then open up and let excess fuel return to the tank as the fuel pressure increases due to acceleration and engine rpm, that’s the way the fuel boss is designed. So that being said I am leaning toward the bypass  valve sticking or not sealing when the fuel gets warm. I took the valve apart and inspected it and there was absolutely no debris or any  other matter inside so maybe it’s sticking open when fuel gets warm. When the psi dropped to below 10 I pulled over and crawled under truck and tapped on the valve with a screwdriver and bam, My fuel pressure spikes right back to 17psi. I guess I will have to contact Glasier Diesel Power in the morning and see if this valve can be fixed or just replace. 

I have the straw installed stand alone out side the basket It’s cut about 1/8” from bottom of empty tank with two notches just to aid in fuel volume suction 

that return check valve has debris in it keeping pressure from building. this happened to me when i installed mine and tested. took it apart and found some of my teflon tape in there.

Edited March 19, 2019 by CUMMINSDIESELPWR

[01cummins4ever]

20 minutes ago, CUMMINSDIESELPWR said:

that return check valve has debris in it keeping pressure from building. this happened to me when i installed mine and tested. took it apart and found some of my teflon tape in there.

I’ve have taken it apart and checked it a few times in the last few days, never been any debris or anything in it 

I did contact Richard at GDP this morning and he seems to believe the valve maybe hanging up, he suggested to take it apart and change one of the washers to the front side of spring to help the piston seal shut when At idle, That helped a little, at least when I decelerate and the psi drops below 10 it will rebound in a hurry back to normal,  but in the mean time he is sending me a new valve, hope it cures the problem, it’s an expensive little check valve 

10 hours ago, JAG1 said:

Since I have two second gens I installed schrader valves in the fuel lines and purchased a fuel pressure test gauge. It is supposed to be very accurate being that it is an industrial gauge with it's own air bleed button. 

 

I really need to build a good test gauge, is checking at the vp port a good place to hook a test gauge 

[JAG1]

2 hours ago, 01cummins4ever said:

I’ve have taken it apart and checked it a few times in the last few days, never been any debris or anything in it 

I did contact Richard at GDP this morning and he seems to believe the valve maybe hanging up, he suggested to take it apart and change one of the washers to the front side of spring to help the piston seal shut when At idle, That helped a little, at least when I decelerate and the psi drops below 10 it will rebound in a hurry back to normal,  but in the mean time he is sending me a new valve, hope it cures the problem, it’s an expensive little check valve 

I really need to build a good test gauge, is checking at the vp port a good place to hook a test gauge 

I have a Tee in in each fuel line about 18 inches or so before the VP that a schrader valve is threaded into that. I got them from Eric at Vulcan Performace parts. From my limited experience I trust Isspro gauges the most. 

[SilverMoose]

8 hours ago, 01cummins4ever said:

is checking at the vp port a good place to hook a test gauge 

I had my gauge connected to the rest port off the vp44 for quite a while with no issues. If course i had a snubber.

 

L8tr

D

[CUMMINSDIESELPWR]

On 3/18/2019 at 9:47 PM, 01cummins4ever said:

I’ve have taken it apart and checked it a few times in the last few days, never been any debris or anything in it 

I did contact Richard at GDP this morning and he seems to believe the valve maybe hanging up, he suggested to take it apart and change one of the washers to the front side of spring to help the piston seal shut when At idle, That helped a little, at least when I decelerate and the psi drops below 10 it will rebound in a hurry back to normal,  but in the mean time he is sending me a new valve, hope it cures the problem, it’s an expensive little check valve 

I really need to build a good test gauge, is checking at the vp port a good place to hook a test gauge 

yeah it seems the spring isnt putting enough pressure against the ball bearing to seal and build pressure. take it apart and see how easy it is to push it open, 20psi is a lot and if that spring is weak or defective it will not hold pressure. also blow into it and if air gets past then its defective. it happens sometimes

[01cummins4ever]

I got the new check valve installed and cured that problem, holds 17 psi. at idle and 17 -18 psi at wot.

 

next is to run this down past 1/8 tank and see if this draw straw performs  better than the last 

[CUMMINSDIESELPWR]

On 3/22/2019 at 2:08 PM, 01cummins4ever said:

I got the new check valve installed and cured that problem, holds 17 psi. at idle and 17 -18 psi at wot.

 

next is to run this down past 1/8 tank and see if this draw straw performs  better than the last 

nice to hear, sometimes defects happen but the owner of fuel boss is great to work with and very helpful.