Fuel Pressure Problem
 

I just installed a Glacier GFS-392 Performance System. Installation went without a hitch and once the truck started it ran great. Problem is startup, it doesn't want to start. Emailed Richard a Glacier and he sent a writeup describing how to repair.

The problem is that the VP ran with low fuel pressure between 4-11 psi which damaged the diaphragm that seperates the high and low fuel pressure at the VP.

The solution requires disconnecting the ground from the ECM and the ground to the battery from the wires and connecting it to a switch that does not recieve power during cranking.

Has anybody done this? Where did you connect the wire? Which wire is it (ECM)? Should I just reinstall the old lift pump until the VP goes out? Any advice would be helpful.

I know I need to replace the VP but would like to prolong this as long as possible or at least until I figure out which VP to install.

:w:

First I ever heard of this one. I would be interestd in seeing the writeup though if you could either post it or send it to me.

When you bump the starter does the pump run. This is what's supposed to prime the system. I assume your using the factory trigger to run the pump. Also what fuel pressure are you running at right now.

With the new pump around 17+. If the truck sits for a while it starts right up. If I run it and after a couple starts a no start happens. When I removed the relay during the no start, it started up easily (then quickly shut the engine off).
Prime system works, I have a gauge and it shoes pressure.

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Be back in an hour
Honey dues just caught up with me

Sounds to me like your VP is goin. One of the primary symptoms is that it won't start when hot. If you shut the truck off, the VP44 has to cool off before it will re-start. If this is the case there's not much to do about that except replace it, unless Richard has come up with something new.

Not that I'm reccomending for you to do it, but mine started doing that a few years back. At the time I couldn't afford the new pump so I milked it for a few months by carrying a cooler full of gallon jugs of water around with me. If I needed to start the truck back up before it had a chance to cool down I would drown the pump with cold water and it would start right up. ONLY DO THIS IF YOU KNOW YOUR PUMP IS BAD AND YOUR WAITING TO REPLACE IT.

11psi is low pressure????? First Ive heard that :sen:

Even on the 4 psi end, it's a problem but not what I would consider a big one if it's only there for the few seconds at a time when your workin it. Dodge says it can drop to 0 for those short periods of WOT without hurtin it. Not that I'm aggreeing with them, just illustrating the point. That's also why I'm curious to see this write up, this sounds like a whole new concept to prolonging the life of a dying pump if it works.

I'm curious how shutting the ECM off during cranking will help a "no hot start" pump. Pump cool fuel thru it? Or get the diaghram back the way it needs to be? Keep us informed on what works and doesn't.

The problem is there is a diaphram that reacts to high/low pressure from the lif pump (hope I am explaining correctly). If the VP sees higher pressure from the lift pump during startup the truck doesn't start. When I removed the relay, shutting the lift pump off, the truck starts properly.
And
If I let truck sit for a while it starts up.

Once I get home I will post the write up.

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Also
Old lift pump was all over the place. At idle it would drop down to 0, 4, 6 psi etc. Once going pressures would go up to 9 through 11.

I am using a Quadzilla Recon (digital) to read pressure.

That higher pressure your reffering to is the same problem that FASS users had to address when it was new to the market. But they were dealing with 22psi plus pressures that were causing the hard starts.

what was done to correct the problem? when I turn my key on the pressure will go up to 18-19 psi.

I don't know if this helps or not, but here is the way I understand my set-up. I have a walbro set-up (similar to yours from wide open diesel). Mine came with a trigger wire to run from the power wire at the stock lift pump (which is controlled by the ecm) back to the new walbro pump. This trigger wire would send power to the lift pump when you turn the key on to prime the system and then turn the pump off till the truck starts, then powers the pump again.

Did your kit come with a trigger wire to run from the stock lift pump wire?

Scott

It has a relay that connects to the stock lift pump wiring harness.

That's the way it should be.

Let me know if this makes sense

I see two choices
1 I could reintall my old lift pump and deal with fluctuating pressure,

2 install a valve to turn down the pressure to 5-7 psi. I have read on bluechip.com that at this pressure the inj pump would not suffer performance losses. This is a temp bandaid until the inj pump is replaced. Its just hard to replace it when I see 21+mpg on the hwy with great power.

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question is

what type of valve?
ball valve

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i'll answer my own question
needle valve

I won't argue with anything that Chip put's out, he is one of the most knowledgable out there on these pumps. But I don't like it that low. I think it will run just fine off those pressures, I just like a little more cooling factor then that. If your having troulbles with hot start's it's not gonna matter much longer anyway. That's a pretty advanced stage of the pump dying and it's gonna go quick from there.

A commonly overlooked problem on these pumps is the overflow regulator. It's a banjo bolt on the return line of the VP that is spring loaded. It's designed to hold the internal pressure of the pump at 14psi. If this spring gets weak it opens up with to little pressure and let's the fuel return right back to the tank, not getting an adequate supply to the injectors. If it sticks shut it holds to high of pressure and put's the VP into a limp mode so to speak. This is a $14 part from the dealer that you are gonna need to change when you replace the VP anyway. It's always worth a shot. Takes 10 minutes to change and it's cheap.

Scan through this article, it will give you some highlights of your fueling system. https://www.dieselbombers.com/98-5-02-cummins-24v-5-9l-vp-44-tech-talk/2670-guide-24v-fuel-system.html

Great advice will consider a $14 banjo bolt cheap and worth the try. Unfortunatly I will not be able to check it out until next week due to work.
Once I return I will replace the banjo and give an update.

Regarding Richard's write-up, I emailed and ask if I could post it, the write-up is his.

To all that answered
Thanks, its is good to have others with the same interest.

Galcier's write up
Thanks Richard

Spread the knowledge

Usually hard starts are only encountered on the 1998.5 – 2002 Dodge Cummins with the VP44 injection pump. If this occurs it is usually on a VP44 with high mileage, and/or a VP44 that has been subjected to around 5psi of fuel pressure or less. It is more likely to occur when the weather is warmer/hot.

Explanation of Diaphragm: The diaphragm in the VP44 is designed to move about .5mm with proper fuel pressure (about 7psi min.). When the VP44 is subject to about 5psi or less the diaphragm can move up to 2mm, an increase in movement of 4 times more than what it was designed to move. With this type of movement the diaphragm will eventually develop stress cracks thru out the body of the diaphragm.

One job of this diaphragm is to separate low fuel pressure and high fuel pressure in the housing of the VP44, when the cracks are present this separation does not occur. This will lead to hard starts even with a stock OEM lift pump!! Here is a simple test:

Note: Not all failed pumps with broken diaphragms will start with low to no fuel supply. Sometimes the diaphragm is so broken that charging pressure is not able to build to a level that allows the pump to deliver fuel. Try starting the vehicle without waiting for the fuel pump to cycle. Meaning when you turn the key to the on position immediately engage starter.

Or:

Unplug the lift pump or remove the fuse so the lift pump does not operate.

Note: If the engine operates without fuel pressure for a period of time the VP44 will be destroyed. Understanding this condition, start the truck. If the truck starts shut it off immediately!!!! This test just indicated that the increased fuel
pressure from the new lift pump is overriding the thinner diaphragm and/or cracked O-rings surrounding the diaphragm in the VP44.

There are a few solutions to this:

1) Repair the VP44. VP44’s were manufactured with a thinner diaphragm which can and will cause hard starts with hot weather and or higher fuel pressures. Thicker diaphragm’s for the VP44 were released around 2003 for correcting this situation. Remember it doesn’t matter if the VP44 has the thinner or thicker diaphragm, if the VP44 has been subjected to a failing transfer pump (lower fuel pressure) or a failed transfer pump it will lead to this problem. The damage was done by the failing or failed lift pump before the new pump was installed.

2) Lower the fuel pressure from the new system.

3) Most customers prefer the higher fuel pressure. If this is the case we recommend an oil pressure switch (Honeywell Hobbs part# 78143) on the ground side. This is done by placing the oil pressure switch in the oil gallery (on top of the oil filter). Then disconnect the ground from the ECM and (if it has it) the ground to the battery from the wires. The ground wire is then connected to the oil pressure switch. This will delay the lift pump until the engine has 3 – 4 pounds of oil pressure.

4) Move the relay power wire from the battery positive to a circuit that isn’t hot during cranking. This will give zero fuel pressure during cranking and allow the pump to come on as soon as the key is released. Good results have been had by using a fuse tap and connecting to the power window circuit in the fuse box itself.

If I'm reading this right it sounds like a lot of work to go through for a temporary fix. If this diaghram is bad your pump is gonna fail. By deleting the trigger relay from the ECM you are just buying yourself a little time for it to fail at an even more inopportune time in the near future. Not to mention the extra time and expense of the pressure switch and other misc items needed.

I may be way off base in my understanding here though.

Shopping for a new vp. I am going to call industrial about their setup on Monday.

If you have the Cash spring for the Hot Rod VP44....

lol

There is one other way to maybe fix your problem. Do you know anyone near you that has a smarty? The reason that I am asking is that the samrty has the newest dodge ECM program on it. That being said what this will do for you is when you install the smarty and uninstall it, it will put the newest version of the dodge software in your truck. The newer revisions of the ECM software will not signal the lift pump to run until the engine has started or you disengage the starter. This would be something eazy to try and would not cost you anything.

Installed an Industrial Injection VP44 this morning. Started right up and runs very well. Need to take it for a drive to determine if there is any improvement.

I do have one problem and that is fuel pressure. A few months ago i installed a Quadzilla recon electronic gauge and noticed that my fuel pressure was all over the place (0-11psi). As a result I purchased an Glacier setup and removed the stock setup. Fuel pressure ~17 - 19 psi but then had a hot start problem come up. Vp was replaced but know the fuel pressure fluctuates from 0-10 at idle and 17 psi at cruising speed.

Would a fuel leak cause this pressure drop?

There is a pre-filter and I recently changed the primary filter.

This is a strange one. A leak in the lines could cause a fluctuation in fuel pressure and if it was between the tank and the lift pump could suck air in and not leak fuel out. But if this were the case it should read lower pressure at WOT then it does at idle.

The only thing I could think of would be if for some reason your pump is not getting enough volts at idle, when you are on the pedal it is sending more voltage through the system. I assume you are using the stock trigger running through a relay to turn the pump on and off. I would start by making sure you have a good ground on the relay. Maybe use an ohm meter to see if your getting good power through the relay since the problem is at idle, this will be easy to do. I would also run your hot wire right off the battery, that is the most fail safe juice you have. Another good source is the starter lug, but I preffer the battery myself.

The first thing your gonna hear from others is don't trust that electronic guage. Set up a mechanical guage to test it with.

This is exactly how my Fass is setup. Turn the key to the on postition, you can here the pump turn on for a second and the fp guage goes to 20 then settles back to zero.

Start the truck and the fp comes up. It's at zero while starting.




YES. At least double check against a good mechanical guage to make sure your set up is reading the same or pretty darn close. That would be a good idea.:up:

Your answer to the leak question makes sense, and, if there were a leak/sucking air the motor would "stumble" under acceleration.

I will check the voltage going to the fuel pump to insure consistence power is supplied shortly.

I will need to buy press tester (Gino $50, is there a cheaper one) that hurts because I purchased the Quadzilla Recon to monitor fuel, egt & boast. Will need to contact Quadzilla again, I just returned their XZT setup because it melted/caught fire under my dash.

Here is the twist, pressure remained constant before I installed the new vp. Only drove ~500 miles after installing the new lift pump due to hard start problems. But during this time fuel pressures were 17+. What does this mean regarding the old vp? The banjo bolt was replaced on the old vp so that is eliminated. Another blockage in the old vp that would cause high pressures? Only problem was hard hot starts, performance was very good but didn’t run long enough to check mileage. (Sunday morning 2 cups of coffee, no food, maybe I am over thinking this and should check the new lift pump and pre filter)

Any thoughts?

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forgot to mention, power wire goes directly to battery, relay connected to stock pump wire.
With the new vp it starts and runs well but have only driven 50 miles since install

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started tracing the wires with my meter and all of a sudden everything works perfect. go figure

With your last statement there it makes me think you have a bad connection someplace. Check all the connections and put some dilithium grease in the connectors just for extra insurance.

Thanks for all the info

Just drove ~150 miles last 2 days and truck is running great. New VP feels responsive and new lift pump keeps pressure 17-19, even at WOT. Topped off the tank and will track milage. Feels great driving my truck.

Was getting 18-21 (depending on traffic) on the freeway before pump went out. Hope the good mpg remain.

Follow up
New VP is great, new lift pump keeps great pressure. Looking back at the problems, I am disappointed with the Quadzilla Recon. The recon gauge was purchased months ago and did not display correct fuel pressures (quadzilla put out a faulty product, will not deal with them again after experincing their customer service, they kept asking for more money). Should have replaced the lift pump long ago it might have saved the VP.
Regarding the VP, again truck works great. Just finished a 400 mile trip, kept my foot lite and got 21.6 mpg at 65-75mph. Changing the VP was not difficult.
Thanks to all

Here ya go......