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Need some help here with a high fuel pressure indication. My Isspro Performax EV2 fuel gauge shows nearly pegged at 100 all the time. It used to show between 60-70 or so, but for the past several weeks, it shows full on pressure. Truck starts and runs fine, all temps and other indicators are all normal at all speeds, towing, etc. Bad gauge? Bad sensor? 7th fetzer valve going?
Lastly, is there anything wrong with running high fuel pressure if the gauge and sensor are working properly?
My experience has been if the fuel pressure goes over 100 psi the pump cuts off momentarily and then comes back on. Leading to a viscous cycling of the pump. My guess is you've got a gauge/sending unit issue.
Must be in the air. My gauge will now read 0.4 psi under hard acceleration. (digital gauge) Since there is no seat of the pants difference on my end, I've either got some incredible tuning, or a bad sending unit. (reads 75 while cruising)
I've had a really dirty pre-pump filter before and know the truck won't get out of it's own way below 20 psi, so I'm guessing I don't really have 0.4 psi.
My Isspro Performax EV2 fuel gauge shows nearly pegged at 100 all the time. It used to show between 60-70 or so, but for the past several weeks, it shows full on pressure.
I would look for an issue on the ground side of the wiring or the sender may be kaput. Easy to confirm with a Fuel Pressure Test.
Originally Posted by pminne
Lastly, is there anything wrong with running high fuel pressure if the gauge and sensor are working properly?
High Fuel Pressure will lead to premature O-Ring, Seal, and Pump Failure. According to "The Book", 80 / 65 psig is max for static and residual pressures respectfully. The pump NEEDS to move fuel to cool itself.
I have the same gage and it is doing the same thing. When you turn the truck off does it go to zero? If it's like mine it will not go to zero with the key off. I was told the sending unit is bad.
Thanks all for the replies. It does not return to zero after shutdown. I can't recall the location of the sender, it's been a few years since I installed it. I can take a look. Why would location matter??? It worked at one point.
My fuel filter is likely due, I will change that out soon. I don't recall that this occurred after a fuel up. I was just driving and noticed it was high and it has been there ever since (many hundreds of miles ago).
I just checked my gage with the truck off. It only goes down to aprox 42.5 lbs. I wonder if it's actually the gage itself that's bad and not the sender? If the sender was bad wouldn't the gage go down to zero when the truck is off??
Why would location matter??? It worked at one point.
My fuel filter is likely due, I will change that out soon.......
Because a sending unit located post filter could just be reading low pressure due to a plugged filter. If that were the problem, changing the filter would fix everything.
Originally Posted by Crewcab Turbo
I just checked my gage with the truck off. It only goes down to aprox 42.5 lbs. I wonder if it's actually the gage itself that's bad and not the sender? If the sender was bad wouldn't the gage go down to zero when the truck is off??
UPDATE: so today the gauge just started to read about 85 and stayed there. Drops a bit when accelerating, so it seems to be working. Is it a bad sender? Thoughts???
I don't recall mine ever going to zero either. Shut truck off would stay at the point at idle pressure. Turn key on gauge resets to zero and goes to KOEO pressure. My sender just went before I pulled the motor. Called Isspro and got new sender and a snubber to help with the vibration. It's the vibration in the motor that kills these sending units. (along W/others)
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High Fuel Pressure
