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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
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Discussion Starter · #1 ·
I have a 01 5.9 24v with 176k miles, and like 2 months ago the sending unit on top of the tank and stock lift pump went out. So brought it to the shop and they put a full fass system, new sending unit, and new TP sensor on. ( TP sensor was acting up for a while.) Got it back about a month ago and the truck was running perfectly but I was only building a max of 10 psi of boost. figured out one of the boots wasn't all the way on. so tightened it back up and the same day put a wicked wheel in the turbo. ( i have a boost elbow from quadzilla on it.) and like 2 days later I really started to notice it, (may have been before). But it took the truck just a little longer to start like half a second to a second longer. sometimes starts pretty much normally other times a half second other times a second longer. I have no codes on dash plugged it into the code reader, still nothing. but when I turn the key on it says fuel pressure is zero. When I crank the truck up it has 15-17 as normal. but I have no loss of power nothing. I don't think it's my VP-44 but I have no idea what. it's not hard starting either just delayed kinda
 

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My truck cranks sometimes upward of 3-4 seconds when the motor is hot. I know it is not the vp44 because I have no other simptons of a bad vp(the truck runs like a TOP) and if I pour cold water on the pump it makes no difference.
From my research, I have gathered that the vp44 is unhappy with anything more the 7psi fuel pressure during crank. In my truck I’m running 20psi to the pump, pair that with a heat soaked motor expanding the metal components in the pump via heat, and it creates somewhat of a bind.

so long as the truck isn’t throwing a code and runs good once it’s running, I don’t think you have a problem to worry about.
 

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0 fuel pressure when cranking is correct if LP is wired correctly. If should give a quick pump1-3 seconds with the key to ON, Then it should run AFTER it starts or you release the starter(bumping the starter gives 25 second run if not started.

It is pressure over 17=20 lb that it does not like when warm, there is a valve in the VP that shuts it down when over 20 lb sometimes.

Slow starts are usually:
Only slightly Weak batteries or dirty cables. Check and clean anyway.

An air leak into the return line, usually at the banjo on back of the head. Check and tighten it anyway.

ECM not booting up correctly, Does Wait To Start light come on immediately with the key to ON?

All bets are off on significantly modified trucks.
 
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0 fuel pressure when cranking is correct if LP is wired correctly. If should give a quick pump1-3 seconds with the key to ON, Then it should run AFTER it starts or you release the starter(bumping the starter gives 25 second run if not started.

It is pressure over 17=20 lb that it does not like when warm, there is a valve in the VP that shuts it down when over 20 lb sometimes.

Slow starts are usually:
Only slightly Weak batteries or dirty cables. Check and clean anyway.

An air leak into the return line, usually at the banjo on back of the head. Check and tighten it anyway.

ECM not booting up correctly, Does Wait To Start light come on immediately with the key to ON?

All bets are off on significantly modified trucks.
how do you wire a fass to run the way the stock lift pump would, as you describe here?(not trying to hijack this thread)

my fass is wired the way the instructions put it, tapping via a fuse tap into a key on power source, so as long as the key is in the run position it’s running at full tilt.

if I wire it the way you describe, it should fix my hard starting issue. I am sure of this because if I pull the fuse tap out and start the truck, it starts right up as it should, but if I shut it off and plug the fass back in, it will crank and crank and crank and then finally fire up.

thanks!
 

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No that is the problem, not the fix. It should be wire with a relay triggered by the ECM lift pump feed. The ECM does not supply enough amps for the Fass but will trigger a relay. The fuel pressure during cranking is what causes the delay or non start, usually when hot.
Direct wiring works on some trucks and lift pumps but some it does not work.
Wait to start light? Banjo on head?
 
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how do you wire a fass to run the way the stock lift pump would, as you describe here?(not trying to hijack this thread)

my fass is wired the way the instructions put it, tapping via a fuse tap into a key on power source, so as long as the key is in the run position it’s running at full tilt.

if I wire it the way you describe, it should fix my hard starting issue. I am sure of this because if I pull the fuse tap out and start the truck, it starts right up as it should, but if I shut it off and plug the fass back in, it will crank and crank and crank and then finally fire up.

thanks!
As BigFish stated, ECM powers a relay. Mine sits in between the fuse box and all of the brake lines on the drivers side. I think there are two brown wires coming from ECM, one red hot wire, then a yellow wire going to lift pump.
 

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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
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Discussion Starter · #7 ·
My truck cranks sometimes upward of 3-4 seconds when the motor is hot. I know it is not the vp44 because I have no other simptons of a bad vp(the truck runs like a TOP) and if I pour cold water on the pump it makes no difference.
From my research, I have gathered that the vp44 is unhappy with anything more the 7psi fuel pressure during crank. In my truck I’m running 20psi to the pump, pair that with a heat soaked motor expanding the metal components in the pump via heat, and it creates somewhat of a bind.

so long as the truck isn’t throwing a code and runs good once it’s running, I don’t think you have a problem to worry about.
Problem is I just got truck back from shop and when I turn key on it says fuel pressure zero but when running 15
 

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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
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32 Posts
Discussion Starter · #8 ·
0 fuel pressure when cranking is correct if LP is wired correctly. If should give a quick pump1-3 seconds with the key to ON, Then it should run AFTER it starts or you release the starter(bumping the starter gives 25 second run if not started.

It is pressure over 17=20 lb that it does not like when warm, there is a valve in the VP that shuts it down when over 20 lb sometimes.

Slow starts are usually:
Only slightly Weak batteries or dirty cables. Check and clean anyway.

An air leak into the return line, usually at the banjo on back of the head. Check and tighten it anyway.

ECM not booting up correctly, Does Wait To Start light come on immediately with the key to ON?

All bets are off on significantly modified trucks.
Wait to start does come on right away. Today it got longer to crank but if I kill it. And wait like a min starts right away. But I think maybe battery because when I turn truck on battery is already pretty low
 

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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
Joined
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32 Posts
Discussion Starter · #9 ·
how do you wire a fass to run the way the stock lift pump would, as you describe here?(not trying to hijack this thread)

my fass is wired the way the instructions put it, tapping via a fuse tap into a key on power source, so as long as the key is in the run position it’s running at full tilt.

if I wire it the way you describe, it should fix my hard starting issue. I am sure of this because if I pull the fuse tap out and start the truck, it starts right up as it should, but if I shut it off and plug the fass back in, it will crank and crank and crank and then finally fire up.

thanks!
I had a shop do it
 

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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
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Discussion Starter · #10 ·
My truck cranks sometimes upward of 3-4 seconds when the motor is hot. I know it is not the vp44 because I have no other simptons of a bad vp(the truck runs like a TOP) and if I pour cold water on the pump it makes no difference.
From my research, I have gathered that the vp44 is unhappy with anything more the 7psi fuel pressure during crank. In my truck I’m running 20psi to the pump, pair that with a heat soaked motor expanding the metal components in the pump via heat, and it creates somewhat of a bind.

so long as the truck isn’t throwing a code and runs good once it’s running, I don’t think you have a problem to worry about.
I also just bumped it waited and cranking pressure is 16 so that might be it
 

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2001 24v cummins. Extended cab short bed SLT Laramie 172k miles, stock except level and tires
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32 Posts
Discussion Starter · #11 ·
0 fuel pressure when cranking is correct if LP is wired correctly. If should give a quick pump1-3 seconds with the key to ON, Then it should run AFTER it starts or you release the starter(bumping the starter gives 25 second run if not started.

It is pressure over 17=20 lb that it does not like when warm, there is a valve in the VP that shuts it down when over 20 lb sometimes.

Slow starts are usually:
Only slightly Weak batteries or dirty cables. Check and clean anyway.

An air leak into the return line, usually at the banjo on back of the head. Check and tighten it anyway.

ECM not booting up correctly, Does Wait To Start light come on immediately with the key to ON?

All bets are off on significantly modified trucks.
I just bumped it lioe you said and waited and cranking is at 16psi but it just started doing this how do I fix it
 

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Wait to start does come on right away. Today it got longer to crank but if I kill it. And wait like a min starts right away. But I think maybe battery because when I turn truck on battery is already pretty low
What do you mean the battery is already pretty low? After you start it you can watch a volt-meter drop? What is your voltage at while running?
 

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Nothing to fix there. Bump of starter should cause 25 second run of 16lb and should be 12-17 when running. When just turning the key to ON it should not run the lift pump or maintain any pressure for more than 1-3 seconds if that. So zero FP when cranking is normal.
Static battery voltage should be around 12.6v(without grid heaters running) and 14v when running. If you think you ahve a battery problem , Remove both batteries, have the load tested, if one is bad repalce both. Clean all terminals and cables, no corrosion allowed inside copper cable.
 
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I have a 01 5.9 24v with 176k miles, and like 2 months ago the sending unit on top of the tank and stock lift pump went out. So brought it to the shop and they put a full fass system, new sending unit, and new TP sensor on. ( TP sensor was acting up for a while.) Got it back about a month ago and the truck was running perfectly but I was only building a max of 10 psi of boost. figured out one of the boots wasn't all the way on. so tightened it back up and the same day put a wicked wheel in the turbo. ( i have a boost elbow from quadzilla on it.) and like 2 days later I really started to notice it, (may have been before). But it took the truck just a little longer to start like half a second to a second longer. sometimes starts pretty much normally other times a half second other times a second longer. I have no codes on dash plugged it into the code reader, still nothing. but when I turn the key on it says fuel pressure is zero. When I crank the truck up it has 15-17 as normal. but I have no loss of power nothing. I don't think it's my VP-44 but I have no idea what. it's not hard starting either just delayed kinda
fuel tube o-rings ...if you park it with nose facing down hill and it starts fine thats your issue...mine does it when parked flat
 
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