lift pump psi gradually dropping..NEED HELP

madd_signtist · 07-13-2008, 05:23 PM

I've got a 2000 dodge diesel with the 5.9 cummins and learned all about fuel pressure when my VP went out two months ago. After weighing my options and non-abundance of cash, I went with adding a second pump back by the tank to help the lift pump. I went with a Wysco (holley blue knockoff) that's rated for 14 psi and 140 gph. After playing with the spring a little for pressure, the setup is doing GREAT for the first 10 or 15 minutes of driving...it idles at 20 psi and I can't pull it below 11 at wide open throttle. But after that 15 minutes, it will just slowly drop down to bare minimum, even at idle. I had a long trip yesterday and by the time I got to the interstate, it was running 12 at idle and I had to stay off the pedal to keep it above 5 psi. I stopped on the side of the road and killed the engine...stretched the spring just a bit more, and it drove fine through the interstate driving and made it back okay. Today I started it and let it idle for a while and it's doing the same thing...starts out at 20 psi idle, but if you let it run enough, it goes all the way down to 5 psi at idle (I shut it off fearing starvation). Any ideas? I'm open for all suggestions...

**patracy** · 07-13-2008, 06:54 PM

It seems to be hit or miss on the "blue" pumps. I'm on my second, but due to my own actions. (I stripped the housing during a reinstall when putting 1/2" lines on my truck) If it dies on me, I'll be forking over the money on a gearotor style pump. (FASS, AirDog, Raptor, Mallory, exc.)

__________________
1999 2500 4x4 Club Cab Sport. ADRENALINE/pulse , BHAF, FBD 150 sticks, full set of gauges, FP light, Holley Blue pump, 1/2" big line kit, Draw straw, 3" glasspack, TC lockup switch, Stealth VP plate, Heated WVO setup, poor man's 'pane setup, BD TC, BD VB, Billet input, Derale pan.
Parts to come: turbo and bigger exhaust, both seriously needed now!

speedntriple · 07-13-2008, 07:01 PM

I know its a bummer man, but after 3 LPs in one year, I bit the bullet and got and AirDog, never worry about fuel pressure again man...

__________________
99 QCLB 4x4 5spd, 5" str8, Southbend Clutch, AFE w/Outerwear, AirDog 150, Banks High Ram, Edge Drag Comp, Autometer gauges,DSS, Ranchand steps & front & rear, MotoMetal wheels,tinted, Pioneer CD/DVD, speakers. Weatherguard Toolbox, spray in liner...

madd_signtist · 07-13-2008, 08:27 PM

Thank you for the replies.

Ugh. Maybe I was wishful thinking, but I was leaning to a problem somewhere else causing the pump to peter out. I mean it did great for almost an hour straight drive on the interstate Saturday....I couldn't pull it down below 10psi at full throttle going 80mph. But here in town, the thing just nearly dies. If it is the pump, I'm thinking getting another stock lift pump and mount it in the holley's location now....as a helper to the stock lift pump (which I tested today and it is dying...giving 9psi at idle and I can flatline it with throttle easily). Main thing is I need to get this back on the road and I don't have nearly the money for the big setups.

speedntriple · 07-13-2008, 08:33 PM

you can keep throwing stock LPs at it.. thats what I did till I had the $ for the Airdog, 1 year warranty on the stockers and take em right back to advance or autozone every few months or so... Mine did the same as yours tho... be good for a while and gradually get worse and worse.... save yourself the trouble and get a good pump as soon as you have the cash...

__________________
99 QCLB 4x4 5spd, 5" str8, Southbend Clutch, AFE w/Outerwear, AirDog 150, Banks High Ram, Edge Drag Comp, Autometer gauges,DSS, Ranchand steps & front & rear, MotoMetal wheels,tinted, Pioneer CD/DVD, speakers. Weatherguard Toolbox, spray in liner...

**patracy** · 07-13-2008, 08:39 PM

I run only one pump.

Don't bother with another "stock" lift pump. You'll be in the same place again.

The cheapest thing to try would be this. Wire up a relay for the fuel pump, triggered from the power for the original fuel pump. (This ensures full voltage to your pump). Ditch the factory pump. Having the pump on the side of the motor works against you. It's exposed to heat. It's trying to "pull" fuel, instead of push. The blue, when healthy, has all the pressure and flow needed for the truck. Next see if you can get by with replacing the pressure spring. Just take it to a hardware store and try to match it. You could also try cutting a coil off it. This will increase pressure.

Also while your at it, pull the valve out behind the spring and sand it down smooth.

__________________
1999 2500 4x4 Club Cab Sport. ADRENALINE/pulse , BHAF, FBD 150 sticks, full set of gauges, FP light, Holley Blue pump, 1/2" big line kit, Draw straw, 3" glasspack, TC lockup switch, Stealth VP plate, Heated WVO setup, poor man's 'pane setup, BD TC, BD VB, Billet input, Derale pan.
Parts to come: turbo and bigger exhaust, both seriously needed now!

**Diesel-Dan** · 07-14-2008, 09:07 AM

OK...let me take a stab at this one:

You have a mechanical gauge...with an isolator??????

IF you do....check your isolator....you have air in the gauge side or need to bleed out the diesel side. I would do both.

OR just take the isolator out of the system and run diesel to the gauge.....

__________________
Dan MacDonald
www.FASSRide.com

2001 2500, 4x4, Con OFEed, TBK, AFE Stage II kit W/ prefilter and 4" cowl mod. , FASS 150/150, Mach 2's, Drag Comp,

Currently running on B-100
'02 Jetta TDI 5 Speed "Mini Me" 45-50 MPG

madd_signtist · 07-14-2008, 08:16 PM

I have an ISSPRO gauge that has a nylon tube running directly to the tapped banjo inlet at the vp44...don't have an isolator, but I did use some extra fuel hose to cover the nylon tube and the fitting on the cab side...just in case it leaks or blows open someday.

I'm thinking the pump may be dead-heading with the stock LP...I'm noticing just before it starts petering out, I will get surging...a lot of wavering at idle and I can hear the pump sound like it's drowning....then the psi just starts sinking...surging all the time.

I've been stretching the spring to get more pressure on the holley blue...am I supposed to be shortening it?

madd_signtist · 07-14-2008, 08:19 PM

Sorry...and I do have the relay going for me. It's 12V with splices going to the stock lp and the battery with ground. I'm sure it's working because both pumps kick on/off together.

***Rollin Coal*** · 07-14-2008, 09:36 PM

Quote:

Originally Posted by madd_signtist

I have an ISSPRO gauge that has a nylon tube running directly to the tapped banjo inlet at the vp44...don't have an isolator, but I did use some extra fuel hose to cover the nylon tube and the fitting on the cab side...just in case it leaks or blows open someday.

I'm thinking the pump may be dead-heading with the stock LP...I'm noticing just before it starts petering out, I will get surging...a lot of wavering at idle and I can hear the pump sound like it's drowning....then the psi just starts sinking...surging all the time.

I've been stretching the spring to get more pressure on the holley blue...am I supposed to be shortening it?

sounds like the stock pump is going out and becoming a restriction... get it outta there. i still have my stock pump on the block but its completly bypassed w/ the airdog. i figure one day ill use it for water injection. see how long it lasts lol.

__________________
Thanks to Diesel Auto Power ...... '01 - 2500 53 Block ...... 600+ HP Build Up Thread

**Diesel-Dan** · 07-15-2008, 11:09 AM

Quote:

Originally Posted by rock kustoms

i still have my stock pump..........i figure one day ill use it for water injection. see how long it lasts lol.

Ill save you the trouble....with the metal vanes....not long at all!

__________________
Dan MacDonald
www.FASSRide.com

2001 2500, 4x4, Con OFEed, TBK, AFE Stage II kit W/ prefilter and 4" cowl mod. , FASS 150/150, Mach 2's, Drag Comp,

Currently running on B-100
'02 Jetta TDI 5 Speed "Mini Me" 45-50 MPG

JaredMTFD · 07-15-2008, 11:27 AM

As already mentioned, you need to bypass your stock pump. It is just a hindrance. I had the same issue when I bought this truck. The previous owner and a holley pump by the tank pushing through the stock pump. Fuel PSI was crazy.
I got a vulcan big-line fuel kit: Vulcan Pusher Pump System™ for 98.5 to 02
It gets rid of the stock fuel lines and bypasses the stock pump. Also has an easy connection for fuel pressure reading.
Use the relay like you are from the stock harness, just dis-connect the stock pump. The vulcan kit comes with a harness that plugs into the stock pump harness, so it's easy to tap for the relay.

Also, as mentioned, if you have an isolator for your fuel pressure gauge, either check to make sure it's working properly, or get rid of it. I couldn't figure out why I had no fuel pressure. I bought new pumps, bled the system, stretched springs, over and over again, and had little to no psi. What was actually wrong was the isolator was junk. I bypassed it and found that i had 30+ psi. My pumps were actually overheating and shutting down, from pumping so hard 'cause I was stretching the spring so much. Got rid of the isolator, now I have an accurate reading. Just put in a little needle valve in case you ever do have a leak, you can shut it off in a couple seconds.

I'm using a pro-comp black (holley black knockoff) that i got off ebay for about $50. Been going for about 8 months at 15psi with no problems.

__________________
Truck: 2001 Ram 2500. Quadcab, Longbed, 4x4, HO, NV5600 6-Speed
Mods: Leveling Kit, Southbend Clutch, 5" Straight Exhaust, BHAF w/Outerwears and custom heatshield, 40hp Injectors, 70hp Timing Program in Computer, Quadzilla 120HP Xzillaraider, Vulcan Big-Line Fuel kit w/Holley Blue pump, Dipricol FP, Pyro, Boost Gauges
Extras: XM Radio, VHF Mobile Radio, Strobe/LED Emergency Lighting,
Security System: Ruger P95 9MM in door pocket. WWW.FARMBOYSDIESEL.COM

07-13-2008, 05:23 PM	#1 (permalink)
madd_signtist Newbie Join Date: Jul 2008 Posts: 5 madd_signtist's Truck Pics	lift pump psi gradually dropping..NEED HELP I've got a 2000 dodge diesel with the 5.9 cummins and learned all about fuel pressure when my VP went out two months ago. After weighing my options and non-abundance of cash, I went with adding a second pump back by the tank to help the lift pump. I went with a Wysco (holley blue knockoff) that's rated for 14 psi and 140 gph. After playing with the spring a little for pressure, the setup is doing GREAT for the first 10 or 15 minutes of driving...it idles at 20 psi and I can't pull it below 11 at wide open throttle. But after that 15 minutes, it will just slowly drop down to bare minimum, even at idle. I had a long trip yesterday and by the time I got to the interstate, it was running 12 at idle and I had to stay off the pedal to keep it above 5 psi. I stopped on the side of the road and killed the engine...stretched the spring just a bit more, and it drove fine through the interstate driving and made it back okay. Today I started it and let it idle for a while and it's doing the same thing...starts out at 20 psi idle, but if you let it run enough, it goes all the way down to 5 psi at idle (I shut it off fearing starvation). Any ideas? I'm open for all suggestions...

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07-13-2008, 06:54 PM	#2 (permalink)
patracy GA Chapter Vice President Join Date: Oct 2007 Location: Buchanan, GA Posts: 1,627 patracy's Truck Pics	It seems to be hit or miss on the "blue" pumps. I'm on my second, but due to my own actions. (I stripped the housing during a reinstall when putting 1/2" lines on my truck) If it dies on me, I'll be forking over the money on a gearotor style pump. (FASS, AirDog, Raptor, Mallory, exc.) __________________ 1999 2500 4x4 Club Cab Sport. ADRENALINE/pulse , BHAF, FBD 150 sticks, full set of gauges, FP light, Holley Blue pump, 1/2" big line kit, Draw straw, 3" glasspack, TC lockup switch, Stealth VP plate, Heated WVO setup, poor man's 'pane setup, BD TC, BD VB, Billet input, Derale pan. Parts to come: turbo and bigger exhaust, both seriously needed now!

07-13-2008, 07:01 PM	#3 (permalink)
speedntriple Cummins Fan Join Date: Sep 2007 Location: dublin, va Posts: 88 speedntriple's Truck Pics	I know its a bummer man, but after 3 LPs in one year, I bit the bullet and got and AirDog, never worry about fuel pressure again man... __________________ 99 QCLB 4x4 5spd, 5" str8, Southbend Clutch, AFE w/Outerwear, AirDog 150, Banks High Ram, Edge Drag Comp, Autometer gauges,DSS, Ranchand steps & front & rear, MotoMetal wheels,tinted, Pioneer CD/DVD, speakers. Weatherguard Toolbox, spray in liner...

07-13-2008, 08:27 PM	#4 (permalink)
madd_signtist Newbie Join Date: Jul 2008 Posts: 5 madd_signtist's Truck Pics	Thank you for the replies. Ugh. Maybe I was wishful thinking, but I was leaning to a problem somewhere else causing the pump to peter out. I mean it did great for almost an hour straight drive on the interstate Saturday....I couldn't pull it down below 10psi at full throttle going 80mph. But here in town, the thing just nearly dies. If it is the pump, I'm thinking getting another stock lift pump and mount it in the holley's location now....as a helper to the stock lift pump (which I tested today and it is dying...giving 9psi at idle and I can flatline it with throttle easily). Main thing is I need to get this back on the road and I don't have nearly the money for the big setups.

07-13-2008, 08:33 PM	#5 (permalink)
speedntriple Cummins Fan Join Date: Sep 2007 Location: dublin, va Posts: 88 speedntriple's Truck Pics	you can keep throwing stock LPs at it.. thats what I did till I had the $ for the Airdog, 1 year warranty on the stockers and take em right back to advance or autozone every few months or so... Mine did the same as yours tho... be good for a while and gradually get worse and worse.... save yourself the trouble and get a good pump as soon as you have the cash... __________________ 99 QCLB 4x4 5spd, 5" str8, Southbend Clutch, AFE w/Outerwear, AirDog 150, Banks High Ram, Edge Drag Comp, Autometer gauges,DSS, Ranchand steps & front & rear, MotoMetal wheels,tinted, Pioneer CD/DVD, speakers. Weatherguard Toolbox, spray in liner...

07-13-2008, 08:39 PM	#6 (permalink)
patracy GA Chapter Vice President Join Date: Oct 2007 Location: Buchanan, GA Posts: 1,627 patracy's Truck Pics	I run only one pump. Don't bother with another "stock" lift pump. You'll be in the same place again. The cheapest thing to try would be this. Wire up a relay for the fuel pump, triggered from the power for the original fuel pump. (This ensures full voltage to your pump). Ditch the factory pump. Having the pump on the side of the motor works against you. It's exposed to heat. It's trying to "pull" fuel, instead of push. The blue, when healthy, has all the pressure and flow needed for the truck. Next see if you can get by with replacing the pressure spring. Just take it to a hardware store and try to match it. You could also try cutting a coil off it. This will increase pressure. Also while your at it, pull the valve out behind the spring and sand it down smooth. __________________ 1999 2500 4x4 Club Cab Sport. ADRENALINE/pulse , BHAF, FBD 150 sticks, full set of gauges, FP light, Holley Blue pump, 1/2" big line kit, Draw straw, 3" glasspack, TC lockup switch, Stealth VP plate, Heated WVO setup, poor man's 'pane setup, BD TC, BD VB, Billet input, Derale pan. Parts to come: turbo and bigger exhaust, both seriously needed now!

07-14-2008, 09:07 AM	#7 (permalink)
Diesel-Dan FASS Tech Dept. Join Date: Dec 2005 Location: Marthasville, MO Posts: 996 Diesel-Dan's Truck Pics	OK...let me take a stab at this one: You have a mechanical gauge...with an isolator?????? IF you do....check your isolator....you have air in the gauge side or need to bleed out the diesel side. I would do both. OR just take the isolator out of the system and run diesel to the gauge..... __________________ Dan MacDonald www.FASSRide.com 2001 2500, 4x4, Con OFEed, TBK, AFE Stage II kit W/ prefilter and 4" cowl mod. , FASS 150/150, Mach 2's, Drag Comp, Currently running on B-100 '02 Jetta TDI 5 Speed "Mini Me" 45-50 MPG

07-14-2008, 08:16 PM	#8 (permalink)
madd_signtist Newbie Join Date: Jul 2008 Posts: 5 madd_signtist's Truck Pics	I have an ISSPRO gauge that has a nylon tube running directly to the tapped banjo inlet at the vp44...don't have an isolator, but I did use some extra fuel hose to cover the nylon tube and the fitting on the cab side...just in case it leaks or blows open someday. I'm thinking the pump may be dead-heading with the stock LP...I'm noticing just before it starts petering out, I will get surging...a lot of wavering at idle and I can hear the pump sound like it's drowning....then the psi just starts sinking...surging all the time. I've been stretching the spring to get more pressure on the holley blue...am I supposed to be shortening it?

07-14-2008, 08:19 PM	#9 (permalink)
madd_signtist Newbie Join Date: Jul 2008 Posts: 5 madd_signtist's Truck Pics	Sorry...and I do have the relay going for me. It's 12V with splices going to the stock lp and the battery with ground. I'm sure it's working because both pumps kick on/off together.

07-15-2008, 11:27 AM	#12 (permalink)
JaredMTFD www.myspace.com/jaredmtfd Join Date: Jan 2007 Location: Henryville, Indiana Posts: 577 JaredMTFD's Truck Pics	As already mentioned, you need to bypass your stock pump. It is just a hindrance. I had the same issue when I bought this truck. The previous owner and a holley pump by the tank pushing through the stock pump. Fuel PSI was crazy. I got a vulcan big-line fuel kit: Vulcan Pusher Pump System™ for 98.5 to 02 It gets rid of the stock fuel lines and bypasses the stock pump. Also has an easy connection for fuel pressure reading. Use the relay like you are from the stock harness, just dis-connect the stock pump. The vulcan kit comes with a harness that plugs into the stock pump harness, so it's easy to tap for the relay. Also, as mentioned, if you have an isolator for your fuel pressure gauge, either check to make sure it's working properly, or get rid of it. I couldn't figure out why I had no fuel pressure. I bought new pumps, bled the system, stretched springs, over and over again, and had little to no psi. What was actually wrong was the isolator was junk. I bypassed it and found that i had 30+ psi. My pumps were actually overheating and shutting down, from pumping so hard 'cause I was stretching the spring so much. Got rid of the isolator, now I have an accurate reading. Just put in a little needle valve in case you ever do have a leak, you can shut it off in a couple seconds. I'm using a pro-comp black (holley black knockoff) that i got off ebay for about $50. Been going for about 8 months at 15psi with no problems. __________________ Truck: 2001 Ram 2500. Quadcab, Longbed, 4x4, HO, NV5600 6-Speed Mods: Leveling Kit, Southbend Clutch, 5" Straight Exhaust, BHAF w/Outerwears and custom heatshield, 40hp Injectors, 70hp Timing Program in Computer, Quadzilla 120HP Xzillaraider, Vulcan Big-Line Fuel kit w/Holley Blue pump, Dipricol FP, Pyro, Boost Gauges Extras: XM Radio, VHF Mobile Radio, Strobe/LED Emergency Lighting, Security System: Ruger P95 9MM in door pocket. WWW.FARMBOYSDIESEL.COM