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Guest Mopar1973Man

FUEL PRESSURE GAUGE - All trucks require one!

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Guest Mopar1973Man

The fuel system on our trucks is weak at best. I would highly suggest you get a fuel pressure gauge at least. This will protect your VP44 injection pump from extremely low pressure or a fail lift pump from ruining your VP44. The minimum fuel pressure by the Dodge FSM book is 10 PSI but there are a few people here that say its safe to go down to 7-8 PSI.

There is few things you can do to improve the system.

Larger fuel lines (Vulcan Big Line Kit), Bigger Fuel pumps (FASS or Walbro), and relocate the pump closer to the tank.

Some of you might have the in-tank replacement from the dealer. If so you can stack to pumps together to improve the pressure.

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I have always heard 5psi.

Really as long at you have positive pressure it's good. That means the injection pump isn't trying to suck fuel.

At least that's my story.

170,000 miles on the stock VP44 and lift pump :D

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Guest Mopar1973Man

Here is a copy of the page from the 2001 Dodge FSM book straight from dodge...

FP2.jpg

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dang it now i have to read more that one section in the index bit the bullet and bought the wife an 01 we have on order boost pyro and fp guages also when she saves up a little more i think we are going to get the fass 95gph system do you think it would be wise to get the vulcan bigline kit with this system now i gotta add more to my sig :thumbup:

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Guest Mopar1973Man
I have always heard 5psi.

Really as long at you have positive pressure it's good. That means the injection pump isn't trying to suck fuel.

At least that's my story.

170,000 miles on the stock VP44 and lift pump :D

Funny part is I lost my first VP44 at 60K miles and my stock LP had 8 PSI pressure at WOT. It threw the P0216 code twice back to back. :roll:

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That chart really doesn't make sense IMO because a stock truck with stock everything won't flow 10psi at WOT.

My buddy has an 01 with the Edge setup and he can pull it down to 5-6psi on the lowest setting. Even at idle it only shows 11-12psi usually.

I'm not sure on my truck. All I have is a under 5psi light from BD or Bully Dog.. I forget now. It's never lit up yet other than when I first turn the key on. For shits I unplugged the lift pump the other day with the truck running and the light came on... so I know it works.

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Guest Mopar1973Man

This is the only time I had low pressure with stock 6mm lines and banjos I got 13 @ idle, 11 @ 65 MPH, 7 WOT (This is where I lost my VP44)

Stock power no boxes I use to get 14 @ Idle, 12-13 @ 65 MPH, and 12 @ WOT with Vulcan big line...

Now with the Edge Comp, Carter Campaign pump, and Vulcan Big Line I'm getting 14 @ idle, 12 @ 65 MPH, 10 @ WOT (Comp 5x5)

I'm able to stay above 10 PSI but barely.

My buddy has an 01 with the Edge setup and he can pull it down to 5-6psi on the lowest setting. Even at idle it only shows 11-12psi usually

So I would say your buddy had a weak lift pump. Remember the VP44 will continue to pump fuel even without the LP running. But it will cause damage to it quickly because of the lack of lubrication and cooling... That why the extra pressure is required. The extra fuel flow is for this purpose.

Good Rule of Thumb... You Can't Have Volume Without Pressure!

That chart really doesn't make sense IMO because a stock truck with stock everything won't flow 10psi at WOT.

Is a good reason why a lot of VP44 failed. There was little to no fuel flow for lubrication and cooling at WOT. 99%-100% of all the fuel was being injected and nothing left over for lubrication and cooling. This is a good reason why a lot of high performance guys head for the 15-20 PSI range to make sure there is enough fuel for WOT operation. The overflow valve opens at 14 PSI... So this insures that the pump it getting plenty of fuel.

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your rule of thumb... you can't have volume without pressure is not correct. it should read you can't have pressure without volume :smart: . It is the resistance of volume that causes pressure. Think of it this way you have a pipe with water flowing through it and you tapped a gauge in the pipe with the end wide open little or no pressure than start closing the end off and watch the pressure rise. pumps don't pump pressure they pump volume. I've seen this quoted twice and had to say something. I will now get off my :rant:

Now I don't know much about the 24v fuel systems other that what I've read here. are you taking your readings before or at the pump body or after the pump. Is there a pressure regulator in the return line IMHO the gauge should be between the pump and pressure regulator to have a accurate reading

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Guest Mopar1973Man
NOt sure where the sesnor is. It is where edge puts it. I willhave to look into it more.

simple...

Here is boost pressure...

DSCF1717.JPG

Here is fuel pressure...

DSCF1898.JPG

(found on the bottom of the filter housing)

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The newer pumps aren't as strong as the older ones, when I took my OEM pump out last year it was doing 16.5 at idle and 13-14 WOT with the big line kit. Thats stock engine of course.

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Guest Mopar1973Man

Yeah... That's why most people will start moving over to Walbro or FASS system for fuel pumps. I'm find my pump slowly dieing again. It's still runable but it not as strong as it was out of box box now. :roll: Typical carter pumps...

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In regards to gauges and such for monitoring fuel PSI...

About 4 times since I've owned this truck, and have had gauges and other fuel flow enhancements installed, I've lost or nearly lost fuel flow - but didn't know it until the engine began running strangely.

The gauges are certainly a plus, but we can't be watching them at all times!

SO, as an aid, I've gathered components to install both a visual and audible alarm on my fuel system that will trigger if fuel PSI drops below about 5 PSI - here's the components:

alarmqy0.jpg

The above fittings and Hobbs switch will install between my pressure line to my electric gauge sender right here:

psisens6iw.jpg

The round device seen in the parts pic, is a chime similar to other alarms used in the truck - clearly audible, but not objectionable - it's a common Radio Shack item. The red LED seen, is a flashing LED that I plan to install in the window pillar mount used in my dual gauge setup - I'd like to mount the chime in there as well, but not sure if there's room for it.

Total cost for all parts so far has been slightly over $30.

ANYWAY, if I again lose fuel pressure, I'll have *3* warning indicators, instead of just one! ;):D

OK - here's a pointer to a vid of the finished project - so those interested can enjoy all the sights and sounds! :D :-laf

And for the no-vid guys, here's a shot underhood showing the added Hobbs switch set to trigger the alarm at about 7 PSI:

hobbswn4.jpg

And here's the gauge pod, with the large flasher LED seen at the top gauge area:

alamgaugeto3.jpg

As to the pump I'm using, it's a Walbro GSL-392 - my install looks like this, the Walbro in the foreground is the primary, with the relocated OEM Carter still in there for emergency backup if needed:

walbrohb9.jpg

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Haven heard of buzzers being used, lots of guys using the warning lights though. Whatever works as long as you protect that VP!:ok:

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I kind of like the alarm idea....

A guy I know had someone install a 'light' for him.... The guy put it in the knee bolster directly below the steering column. I'm not sure you could ever see it come on! (Well, not without wrecking the truck!)

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