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Just changed my fuel filter, truck has not been the same since!


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Here is the deal. Saturday I flipped up the drain valve for the fuel filter canister to drain the fuel out. I unscrewed the lid for the fuel filter, pulled the old one out. Snapped the new one into place and made sure the new gasket was seated. Fuel filter canister looked clean so I installed the new filter. Pushed the drain valve back down. turned the key to on and I could hear the lift pump working to fill the filter canister back up. Repeated this two more times. Started the truck and it ran good for a couple seconds then died. I then repeated the same process with turning the key thinking it still did not have enough fuel in the filter housing. Cranked it three times and it was cranking strong but still no start. Had it cranking for maybe 15 seconds start but still no fire. Left the key turned to on for about a minute to try and get the filter housing full of fuel. I finally pulled the new filter back out and turn the key to run and the canister filled all the way up. I had to displace a little fuel to get the filter to screw back down. Bumped the starter twice, then cranked it and it fired up and started running smooth again. Two problems since then. 1) my drain valve is leaking pretty steady at idle. Figure the o rings are bad so I just purchased an entire new drain valve and o rings from fleetguard and should be receiving that in a couple days. So I should have that problem solved. 2) When cruising at a steady speed it seems like the truck surges very slightly every once in a while. Passengers cannot notice it but I can. I dont remember it doing this before I changed the filter. Could there be air in the lines and that cause a surging? Did I fry my vp44 by cranking it without fuel? I already attempted to reset the APPS and it didnt solve the problem. Truck starts and runs great now with plenty of power, I just can notice the slight surge while maintaining a steady speed. Any thoughts? Unfortunately I have no way to check fuel pressure right now :banghead:

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If you are leaking fuel than you are definitely introducing air into the system. Get your leak fixed and I bet your stumble goes away. I wouldnt worry too much. Once you get your new drain valve installed let us know if it fixes the problem. In the future when you go to prime the system, I find it helps to purge the air from the system before cranking the truck. I have the older style canisters and there is a port right on top of the canister where I can crack a small valve open just a little to allow the lift pump to push out any air entrapped in the canister. Once I see solid fuel coming out I shut the valve off and start the truck and never have to crack an injector.Oh yeah, get a fuel pressure gauge! :wink:

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If you are leaking fuel than you are definitely introducing air into the system. Get your leak fixed and I bet your stumble goes away. I wouldnt worry too much. Once you get your new drain valve installed let us know if it fixes the problem. In the future when you go to prime the system, I find it helps to purge the air from the system before cranking the truck. I have the older style canisters and there is a port right on top of the canister where I can crack a small valve open just a little to allow the lift pump to push out any air entrapped in the canister. Once I see solid fuel coming out I shut the valve off and start the truck and never have to crack an injector. Oh yeah, get a fuel pressure gauge! :wink:

Thanks man. Should I crack an injector after I install the new drain valve? And I am going to borrow a fuel pressure gauge to put on the vp44 to check the pressure just in case.
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I experienced the same kind of gremlin earlier this spring. The Pressure Regulator banjo bolt located on the vp44 return port had a broken spring and was not seating the ball in the valve, which wasn't keeping fuel in the vp44. Fuel pressure was at best 7psi. After putting in a new pressure check valve my pressures went to 12psi. The valve is to open at 14psi. When coming off the freeway it would go into a choppy idle until the fuel pump caught back up. That was with a stock FP and now I have a FASS and an ISSPRO pressure gauge and the pressure is good (17psi at wot) and no more choppy idle.

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While I am waiting for my new drain valve I want to figure out how I am going to test my fuel pressure.

Was planning to rent a gauge from Auto Zone, looks like they have a ton of different fittings, hope one will fit on the vp44 text port.

On my truck's test port however there is a sensor for a monitor or EV2 gauge. I do not have either.

Can I simply unscrew that sensor and still be able to check the fuel pressure or does that sensor remove the pressure fitting that you use to test fuel pressure.

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While I am waiting for my new drain valve I want to figure out how I am going to test my fuel pressure.

Was planning to rent a gauge from Auto Zone, looks like they have a ton of different fittings, hope one will fit on the vp44 text port.

On my truck's test port however there is a sensor for a monitor or EV2 gauge. I do not have either.

Can I simply unscrew that sensor and still be able to check the fuel pressure or does that sensor remove the pressure fitting that you use to test fuel pressure.

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It appears that the test port is gone and tapped banjo bolt has been installed in its place. you could just re install a test port, all you need is the parts and they should not cost that much. Vulcan performance should have what you need.
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This is a absolute nono should never install a pressure gauge or a pressure sensors at the VP44. Water hammer pulse are the strongest at the VP44 since its the device that creates the water hamme pulses. All gauge hook up should be done back by the stock filter can if you want a gauge to last. :whistle:

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dang thanks for the heads up guys. Ill rip that out and get the factory test port in there asap. And you think Vulcan will have it?

I can't find the stock one per say but ask Eric about it. But if that doesn't pan out I know he's got these... Schrader Valve - Which will fit your Tapped banjo bolt. http://www.vulcanperformance.com/Brass-Schrader-valve-p/31482.htm Tapped banjo - which you've already got. http://www.vulcanperformance.com/Tapped-Banjo-Bolt-p/tbb.htm
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I can't find the stock one per say but ask Eric about it. But if that doesn't pan out I know he's got these... Schrader Valve - Which will fit your Tapped banjo bolt. http://www.vulcanperformance.com/Brass-Schrader-valve-p/31482.htm Tapped banjo - which you've already got. http://www.vulcanperformance.com/Tapped-Banjo-Bolt-p/tbb.htm

ok so I should be able to just order that Schrader valve and be good to go? Update: I replaced the fuel filter drain valve yesterday and the truck seems like its running much better. Felt it surge a couple times until it warmed up then after a couple minutes it ran great. Only thing I notice is that it takes a little longer to start than it did before (by like one or two seconds, nothing major) I'll be able to track everything down after I know the fuel pressure :banghead:
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ok so I should be able to just order that Schrader valve and be good to go? Update: I replaced the fuel filter drain valve yesterday and the truck seems like its running much better. Felt it surge a couple times until it warmed up then after a couple minutes it ran great. Only thing I notice is that it takes a little longer to start than it did before (by like one or two seconds, nothing major) I'll be able to track everything down after I know the fuel pressure :banghead:

Yeah... You should be able to swap the sender for the schrader...
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This is a absolute nono should never install a pressure gauge or a pressure sensors at the VP44. Water hammer pulse are the strongest at the VP44 since its the device that creates the water hamme pulses. All gauge hook up should be done back by the stock filter can if you want a gauge to last. :whistle:

How about with a needle valve to dampen the pressure. I've been running mine like that for about 3 years on a mechanical with an isolator and had no problems, and pressure's have been steady, not jumpy, and have been verified with another gauge. Just curious if that setup is okay.
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  • 2 weeks later...

Does anyone know the size of the hose that runs from a block mounted FASS lift pump into the fuel filter canister? I am leaking a little fuel back by the banjo bolt that bolts into the filter canister and I am thinking that the hose itself is possibly leaking. I tried to tighten the banjo bolt but it was torqued pretty snug so I dont think that is what is leaking. Also I assume I need to use a hose that is rated for fuel when I replace the old hose?

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