We riding home the other day in 10 degree weather and the fuel pressure gauge decided to put on a show. Running only the pump the pressure will stay at 15psi. If I start the truck the pressure starts out at 15 psi but as the charging systems stops wiggleing the amp gauge and it runs with out cycling the alternator the fuel pressure goes up to 30+and stays there. Performance is good and trust me im glad it went high and not the other way but this is silly.It seemed like maybe something was getting in the line up to the sending unit, ice? So its in a heated shop now and the same condition exists. The wiring is all good and turning the screw into the Holley Regulator shows that its not stuck. The snubber in front ofthe sending unit checks good as well. Is this a sending unit failure?Merry Christmas from the NorthlandKal

If its a electric gauge I would check with a mechanical gauge... You mention a snubber are you using a fixed snubber or a needle valve?

Yeah its a needle valve with the sender for the (low pres)light as well as the glowshift sender all wrapped up together up high like yours tied to the brake lines and grounded via single strand heavy wire.

Is your needle valve open too far?

If setup wrong it will wipe out a sender quick... If done right the gauge will last for years... Like my DiPricol gauge is over 7 years old now...

Ya know when you put it like that, maybe. What does a bad sending unit do? Mine seems linked to the alternator now, which it never did. As it runs the pressure goes back and forth evenly as the alt. does its thing 15 psi one second then 30+ for a few back and forth for several minutes as it sits and warms up. This just happened the thing was running along normal for months. But the grid heaters definatley run long and its only Dec.

Being the sender isn't mounted to steel plumbing and is on a rubber hose it sound like a poer ground of the sender or gauge. If not then its a bad sender. Rare but happens lift pump having issues with grid heater hitting? Might check with a mechanical gauge and rule it out...

I run a westac fuel pressure gauge and they do not require a snubber of any sort. Had mine for a while with no issues.

I run a westac fuel pressure gauge and they do not require a snubber of any sort. Had mine for a while with no issues.

Ok Then with the new sender from Glow Shift in hand, replacement accomlished, I turn it on with the key, looks good, I hear the pump running and the gauge works nicely with the needle vavle adjusted to just the proper rise rate. I start the engine and hold my breathe and as soon as the alternator was done giving the batts. all they needed. The pressure goes right back up and pins the needle.

WTF? Its a Blue Pump. I thought that sucker tops out somewher well below 30psi. How does that work?

--- Update to the previous post...

Furthermore Glowshift Customer svc. just told me it must be my charging system.

I had the exact same problem with mine. The solution for me was to reposition the ground wires for the whole gauge setup and ensure a good ground. I used a sheet metal screw into the firewall with better fittings on the wire and better strip and crimp. Mine has been rock solid ever since.

Thats it too Blake im at the point now where the wiring is going to get redone. Id do it now but the girlfirend put too many sweatshirts in the washer and now I have to replace THAT belt.Thanks

Sure sounds like a ground issue to me.

The ground issue has to be something wild. Maybe a tiny hole in the wire insulation propogated into a corroded wire that remains invisible?. I have all the stuff to fix it on hand. I dont want to leave you hangin but its cold out in the shop and for what its worth, it can sit. The cold weather inducing poor mpg have put me in my little Plymouth for the time being and it gets great 30+mileage. Stay tuned.

Why use an electronic fuel pressure gauge in the first place?I see threads on here about none trusting the factory electronic oil pressure gauge. I have a mechanical FP gauge and would not have it any other way. My:2cents:.

Well, Its been nice enough to take another look at the wiring to that gauge. I pulled it out. Thought about replacing it, and changed the whole plan. I got a mechanical gauge. I still have the functioning low pres. light so combined with the cheap mech gauge i got off Ebay. I have something to look at that does NOT run thru wiring. I have a short section of rubber brake line doing the job of getting the gauge up high enough to zip tie it to a brake line. Here's the ? , Do you see any reason why I shouldnt fish thru a longer rubber section into the cab. Short of some sort of freak failure I think this is the end of the problems with fuel pressure monitoring.Thanks Fellas