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Low fuel pressure reading

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Heres a question for ya, on one if my duallies @ WOT the fuel pressure guage reads between 5-7 .At idle its @ 15. I dont think it should go that low. I have a FASS 95 electric fuel pump on it with 110 injectors. Im thinking maybe the 110 injectors are sucking so much fuel the FASS cant keep up? Any thoughts?:rolleyes:

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Have you eliminated the fuel filter as a possible source or fuel restriction? If not the fuel filter, sounds like the fuel pump may be getting weak or sucking air in the system somewhere.

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I forgot to add, try installing a temporary mechanical fuel pressure gauge on the system and check your pressure that you see in the cab against what the mechanical gauge says. A bad fuel isolator separator or isolatore membrane could screw up your pressure readings in the cab. Check you fuel pressure hose and lines to the isolator as well. I going on the presumption that you have a mechanical fuel pressure guage in the cab.

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Mike hello I told you what I have on the truck....lol..its in the question!:whistle:..lol..but i did fill out the sig, but it didnt post it yet. I do have an electric fuel pressure guage on both of the duallies and they both say the same thing. Mind you all the add ons are the same and were put on both trucks at the same time. Yes, I still have the factory fuel filter with a fuel filter before the FASS, both are new.

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What ^^^^ LIveOak ^^^^ said.Sounds like some sort of restriction. I know some guys running bigger injectors that dont see that drop.On the AirDog you can replace the tension spring on the return port (I think) to increase your pressure ...... not sure about the FASS.The temporary mechnical guage in FRONT of the stock filter would show you if your getting the drop somwhere between the stock filter and the tank inlet.

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Mike hello I told you what I have on the truck....lol..its in the question!:whistle:..lol..but i did fill out the sig, but it didnt post it yet.

Humor me... I don't remember everything everyone got... Yeah even I get CRS sometimes... :lol: Stock vs. Big Line... post-2-138698166487_thumb.jpg Stock line is 6mm ID Big Line in 1/2" ID

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stock lines= way to restrictive!!when i had an '03 6-speed the first thing i did was toss the stock lift pump and installed an hpfp 150 from f.a.s.s. and man o man it is night and day difference..seriously!!!it is a :smart: move.

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stock lines= way to restrictive!!when i had an '03 6-speed the first thing i did was toss the stock lift pump and installed an hpfp 150 from f.a.s.s. and man o man it is night and day difference..seriously!!!it is a :smart: move.

I dont have the stock lift pump it was tossed years ago for a FASS95, but now its givin both my duallies fits!:spend:

---------- Post added at 01:37 PM ---------- Previous post was at 01:30 PM ----------

Big lines, huh

Humor me... I don't remember everything everyone got... Yeah even I get CRS sometimes... :lol:

Stock vs. Big Line...

[ATTACH=CONFIG]1289[/ATTACH]

Crs is what I suffer from..LMAO!....I like the Airdog2 just because I dont have to drill any holes, and it comes with a seding unit. Hopefully it will help me out and regain my power!:rolleyes: By adding the airdog with the big line and doing away with the stock filter it should help the restriction.

Stock line is 6mm ID

Big Line in 1/2" ID

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By adding the airdog with the big line and doing away with the stock filter it should help the restriction.

Ummm... I'm kept my stock filter housing and even got a filter in the stock housing... But I ran 1/2" line from tank to VP44... So now my fuel pressure is rock solid... (AirDog 150) Short vid... Cruising 55 and stomp on it to 70 MPH...

http-~~-//www.youtube.com/watch?v=iRoZlLVVxiY

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Ummm... I'm kept my stock filter housing and even got a filter in the stock housing... But I ran 1/2" line from tank to VP44... So now my fuel pressure is rock solid... (AirDog 150) Short vid... Cruising 55 and stomp on it to 70 MPH...

http-~~-//www.youtube.com/watch?v=iRoZlLVVxiY

Why would you keep the stock filter? DOesnt the air dog come with 2 filters??

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The OEM filter especially if you use the Baldwin filter, will still filter about the same and provide a last chance catch for any possible water that may get by the AirDog filters. I consider it VERY cheap insurance.

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Why would you keep the stock filter? DOesnt the air dog come with 2 filters??

Because where I'm at the winter dip down to -20*F around here and the AirDog has no fuel heater... So I kept the sotck housing for the fuel heater. Yes there is a filter in there to to protect the VP44 from inhaling jello (gelled fuel).

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Sooo, if im reading it correctlly it sounds like I can use the exsisiting fuel filter if I want, for added protection. How did you adapt the hose going into theOEM filter, and out? I would of thought that the new AirDog comes with good filters that protect against harmful materials or water.

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Sooo, if im reading it correctlly it sounds like I can use the exsisiting fuel filter if I want, for added protection. How did you adapt the hose going into theOEM filter, and out? I would of thought that the new AirDog comes with good filters that protect against harmful materials or water.

Added filter protection and the fuel heater. The AirDog does come with great filters that do protect against harmful materials and water but it does not have a fuel heater. Perhaps that is a feature they will add to a future AirDog pump.

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Added filter protection and the fuel heater. The AirDog does come with great filters that do protect against harmful materials and water but it does not have a fuel heater. Perhaps that is a feature they will add to a future AirDog pump.

There is a fuel heater in the stock OEM filter housing? Hmmm didnt know that..:shrug: I appreciatte all the info guys!! Going to order them this week just trying to get all the info on them before I order them.:thumbup2:

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There is a fuel heater in the stock OEM filter housing? Hmmm didnt know that..:shrug: I appreciatte all the info guys!! Going to order them this week just trying to get all the info on them before I order them.:thumbup2:

In my opinion, the Baldwin PF7977 is the best filter out there and if you buy them by the case, they cost $10.16 from BFWeb Express: http://www.bfwebexpress.com/ I keep a couple of spare fuel heater elements as well since they are very difficult to get and word has it that they are no longer in production.
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Added filter protection and the fuel heater. The AirDog does come with great filters that do protect against harmful materials and water but it does not have a fuel heater. Perhaps that is a feature they will add to a future AirDog pump.

You can get all kinds of fittings and hose here, http://www.vulcanperformance.com/category-s/181.htm the tappings on the OE filter housing are 12MM. I put a pre-filter on my truck with a compound gauge to check for restriction. Has a 20 micron water seperator filter. post-10097-13869816699_thumb.jpg
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I already had the proper fittings to run 1/2 inch fuel line from the tank to the IP since I had installed the Vulcan Big Line and drawstraw kit. Flman posted a link. If you are not sure, give Eric a call at Vulcan Performance and he can help you put together all of the fittings you will need. This is the Big Line kit that I installed: http://www.vulcanperformance.com/Draw-Straw-II-1-2-in-draw-tube-and-1-2-in-pushlo-p/vpps9804.htm If you are going to install an AirDog or FASS, many of the fittings come in that kit as well as the fuel hose. If you go this route, you will need this kit: http://www.vulcanperformance.com/Draw-Straw-II-1-2-in-draw-tube-and-1-2-in-pushlo-p/ffip.htm Maker sure you have a heat gun or some other means of heating the fuel hose up without melting it. These push lock fittings are a muther to get the hose 100% pushed on the barb in some cases.

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Thanks guys for al the help!! Now i got to decided which of the airdogs to get this week Airdog1 or airdog 2, and which model 100, 150, or 156? Got any thoughts on it??:rolleyes: My upgrades are listed in my sig thanks to Mopar1973!!:thumb1:

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http://www.thoroughbreddiesel.com/airdog/2.htm That AirDog II has the adjustable fuel pressure and flow demand upgrades but costs about $100 more. To be honest, I have never had to touch the fuel pressure adjustment on my AirDog I. For a short time the fuel pressure was staying around 22 psi because my fuel return valve stuck shut but eventually did open and now my fuel pressure stay rock solid at 18 psi. For the most part, you really won't have a need to adjust fuel pressure once everything is set up correctly. If by chance you do need to adjust fuel pressure, it can be done by changing shim washers. If you go with the AirDog I, I would get the AirDog 150. If you go with the AirDog II, I would get the AirDog II165. You can do fine with the AirDog 100 but the AirDog 150 is the same price and leaves room for future mods. It is a coin flip. I guess if I was buying an AirDog now, I would go with the AirDog II 165. I purchased my AirDog from Extreme Diesel: http://www.xtremediesel.com/fuelsystem_1.aspx?page=2 Hope the video's and links help. I am sure others will jump in with their comments and observations too. I am sure you will be happy with either. Good luck! :thumbup2:
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