Fuel pressure help please

[Toshiro]

Truck is 2005 2500 auto no mods (well, just tires/intake/exhaust and pressure box removed).



I installed a fuel pressure gauge approximately 6 months ago. Since then the truck always read approx 8. 5psi at idle and 7psi or so at highway speeds. The needle was always quick to respond. For example, at start up it would jump up to 8. 5psi with in a second or two. Also when I would floor it, the pressure would drop to nearly 4psi by the time I got up to speed but it would go back to 7-8 psi as soon as I let off of the gas



So here’s my issue:

Now when I start up the truck the pressure jumps to approx 2-3psi and holds there. The pressure SLOWLY rises to normal only after I begin driving. It takes approx 8-10 minutes to come up to normal pressure. If I floor the gas the needle quickly drops as usual but takes another few minutes to return to normal pressure. So the gauge is indicating that pressure is rising very slowly only from 2-3psi up to 8psi. I needle rises quickly from zero psi to 2 or 3psi.



Could the anti-freeze on the gauge side of the regulator have leaked out and caused this condition?



Could my stock fuel pump be failing?



Could my gauge just be messed up?



Could the 7 micron fuel filter I installed last week be contributing? (Used to be 10 micron)



Thanks in advance for your thoughts guys, I’m not sure what to check first…. .

Toshiro

 

[CarlsonR]

try a new fuel filter first, i've had them plug up in less then 5k miles.

 

[rbattelle]

Truck is 2005 2500 auto no mods (well, just tires/intake/exhaust and pressure box removed).

I agree with checking/changing fuel filters first, but it sounds a lot like the fuel pump is in its death throes.



Ryan

 

[Toshiro]

The filter is only 1 week old but I'll check it.

If the pump is failing would it exhibit these symptoms? (Take a long time to get to full pressure).....

 

[RMalone]

How cold has it been? Your in Alaska I wouldn't be surprised if you have some water in the bottom of the tank that is freezing and clogging the screen in the fuel sender. The fuel isn't necessarily gelled but it cant get out of the tank because the water is froze. Try putting it in a warm garage overnight and see if it makes a difference.



This happened to me this winter and I was getting the same type of deal you are, except mine would build pressure very slowly and if I kept running it, it would eventually suck itself into a vacume and die, if I bump started it a few times the truck would slowly gain fuel pressure, start and run for a mile or so and then die again. When I would open the water drain on the filter after it died you could hear the air suck into the filter housing. Mind you this happened with two different Walbro pumps (I too thought the pump may have puked). I fought with the sucker for a couple weeks during a pretty cold snap (by Michigan standards). Also I was using powerservice white during the whole ordeal and changed filters a couple of times and never saw any gelling of the fuel, hell I saw no fuel. I added a whole quart of powerservice red, and while it hasn't been as cold since, we have been in the low teens and the problem has not re-occured (knock on wood).



Something to consider anyway. Good luck dude.

 

[ASchwartz]

How do you have the gauge hooked up? I have mine post filter, so it tells me when I need to change the filter. During the winter I notice that the pressure runs low until the fuel gets hotter.



Avi

 

[Toshiro]

We have been going through a cold spell here lately but the truck is stored in the garage every night. Draining the fuel filter reveals no water. Perhaps I am doing it wrong. Is there a better way other than draining it into a jar and looking at it?

 

[Toshiro]

How do you have the gauge hooked up? I have mine post filter, so it tells me when I need to change the filter. During the winter I notice that the pressure runs low until the fuel gets hotter.



Avi

I have the guage hooked up post filter. I did the banjo bolt and isolator. I wonder if the isolator is causing the odd readings. The guage functioned well until last week.

 

[cerberusiam]

I have the guage hooked up post filter. I did the banjo bolt and isolator. I wonder if the isolator is causing the odd readings. The guage functioned well until last week.

Had an ISSPRO that would do that. work fine for a couple of weeks then slowly start dropping pressure. Refill the isolator and all was good far a while. Turned out gauge was bad and had a small internal leak. Replaced it and pressure is rock steady at 7-8 psi from 10 degrees up.

 

[ASchwartz]

When I first put it in I had a slow leak at the gauge and had some of the symptoms that you do. I ended up using teflon tape and that solved the problem. Maybe your cord has chaffed on something causing a small leak.





Avi