Fuel Pressure
Thread Starter
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Postmaster
Joined: Mar 2007
Posts: 2,612
Likes: 2
From: Dunwoody, GA
Fuel Pressure
My fuel pressure gauge has been reading a max 100psi lately. I'm trying to figure out if it's reading correctly or if the sender is busted. If I unplug the wires from the sender it sends the gauge to 0 so it's not anywhere else in the line. It's an electronic sender reading from the test port on the upper fuel filter bowl. Gauge is a ISSPRO Performax.
It reads 100psi as soon as I turn the key to the ON position. I also changed out the fuel filters (to the newer part #) which had no effect on the pressure reading.
It reads 100psi as soon as I turn the key to the ON position. I also changed out the fuel filters (to the newer part #) which had no effect on the pressure reading.
Thread Starter
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Postmaster
Joined: Mar 2007
Posts: 2,612
Likes: 2
From: Dunwoody, GA
No mods to the fuel system. Only a mild street tune. Reads 100 (gauge maxed) at all throttle positions and idle.
Cargo Master
Joined: Jan 2009
Posts: 2,769
Likes: 8
From: Lubbock
Sounds like its a bad sender. Might ohm/ check voltage etc. I saw a post similar to yours brian on a different forum it was said it had something to do with the ground. If I find the post ill send you a link. Might be helpful.
Tuned
Joined: Jul 2009
Posts: 489
Likes: 4
Fellas,
This may be a dumb question. Why would I want to monitor my fuel pressure? I do not have any fuel system mods. Is installing a guage a preventive maintenance measure? If so, i am very interested. What is the benefit knowing fuel pressure.........?
Thanks
This may be a dumb question. Why would I want to monitor my fuel pressure? I do not have any fuel system mods. Is installing a guage a preventive maintenance measure? If so, i am very interested. What is the benefit knowing fuel pressure.........?
Thanks
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Postmaster
Joined: Apr 2009
Posts: 3,839
Likes: 2
Jaybird,
The injectors in your engine are very fussy about fuel pressure. It has been proven that fuel pressures, either too low or too high, kill injectors and damage engines. It is becoming very clear that as more trucks get fuel pressure gauges, the fuel pressure issues are much more common than anyone thought. Low pressure predominates. I had 3 stock fuel pressure regulator springs and one of them was new. They all failed to provide adequate pressure under full throttle runs. Low pressure will kill an injector internally. Ford specs a minimum of 45psi at all times. Ford also specifies that the maximum fuel pressure should not exceed 75psi. More pressure than that will cause o ring failure. This allows un-metered fuel into the combustion chamber. If it gets too bad you can hydro-lock the engine. Fuel pressure gauges are right up there with coolant filters and eot/ect gauges or monitors for the most important upgrades you can do for your truck. I use an Edge Insight for most of my monitoring and an ISSPRO EV2 fuel pressure gauge for that parameter.
Regards
The injectors in your engine are very fussy about fuel pressure. It has been proven that fuel pressures, either too low or too high, kill injectors and damage engines. It is becoming very clear that as more trucks get fuel pressure gauges, the fuel pressure issues are much more common than anyone thought. Low pressure predominates. I had 3 stock fuel pressure regulator springs and one of them was new. They all failed to provide adequate pressure under full throttle runs. Low pressure will kill an injector internally. Ford specs a minimum of 45psi at all times. Ford also specifies that the maximum fuel pressure should not exceed 75psi. More pressure than that will cause o ring failure. This allows un-metered fuel into the combustion chamber. If it gets too bad you can hydro-lock the engine. Fuel pressure gauges are right up there with coolant filters and eot/ect gauges or monitors for the most important upgrades you can do for your truck. I use an Edge Insight for most of my monitoring and an ISSPRO EV2 fuel pressure gauge for that parameter.
Regards
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Hotshot
Joined: Dec 2003
Posts: 15,368
Likes: 121
From: Stuttgart, Ar
I'm glad the message is getting out. I've been screaming this for a long time. I've used a drawstraw and the factory pickup and both cavitate to zero pressure with 7 gallons left in the tank if you make a hard stop. Not all trucks are like this, but many more than people might think.
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Postmaster
Joined: Mar 2007
Posts: 2,612
Likes: 2
From: Dunwoody, GA
I've determined that the gauge sender is bad. The unit is grounded through a central brain or ESP. The other gauges all use the same ground, power, data bus wires so if the ground were bad the others would read bad as well.
Waiting to hear back from the ISSPRO rep on a replacement.
Waiting to hear back from the ISSPRO rep on a replacement.
Freshman User
Joined: Jul 2010
Posts: 34
Likes: 0
After talking with you last week, and reading this, it makes sense. The O-ring failure would explain why it hydro-locked. I haven't touched the truck since talking with you. If I'm going to get under the hood to pull glowplugs I might as well repair/replace the fuel pressure regulator.
Jeff
Senior User
Joined: Sep 2007
Posts: 198
Likes: 0
When I installed my fuel pressure gauge, I didn't have the sender hooked up. I just had power running to the gauge. It would peg at 100 when the key was on. Once I plugged in the sender, and hooked up the unit to the test port on the fuel filter bowl, it started reading right. Maybe ur sender isn't plugged in all the way, or like previously stated, it's bad