Since installing the fuel pressure regulator upgrade kit last summer, my fuel pressure has been consistently reading between 60-65 psi (per Isspro EV2 gauge). This morning when I started my truck, the fuel pressure was reading between 85-95 psi and stayed there. I drove the truck for about 30 minutes hoping it would come down as it warmed up, but it didn't change. Temps were down to around 20 F last night, but that's never been an issue before. I guess the gauge or sender could have suddenly gone bad, but I'll have to get a mechanical gauge to check that or call Isspro to see if they can give me specs on the sender volts/ohms. Until then, anyone know what else might have caused this problem? Could gelled fuel in the return line cause the fuel pressure to suddenly increase?

 

Something wrong w/ the reading OR something is sticking in the fuel pressure regulator (IMO). I suppose if the return line is severely plugged it could cause it.

 

My EV2 zero's itself every time I start the truck. Is it possible the zero didn't happen correctly? Have you started the truck since then to see if the pressure is still too high?

 

David, yes, the gauge zeros out as it should, but then the needle immediately sweeps up to 95 psi. I just got off the phone after speaking to Michael at Isspro and based on some voltage readings I took, it appears my fuel pressure sensor went out. Michael is putting a new one in the mail to me, and that should take care of that.

 

and the right awnser is here.... what he said.

 

Yep, Mark nailed it. And with the luck I've been having lately, I'm glad it was only the sensor, too. An easy fix, thanks to Isspro's great customer support.

 

Just a follow-up on this problem. I received the new sender from Isspro Saturday and put it on. All good, the old sensor was definitely the problem. Previously, I had also been experiencing a constant ±2-3 psi fluctuation of pressure. Now the pressure reading is steady, with only a slight drop on hard accelleration, so it appears that must have been due to the problem sensor as well.

Thumbs up to Mike and Gary at Isspro. Awesome customer support!

 

I guess I should give these guys a call. My gague has bounced all over the place since I installed it last year as well. I just thought it was the way it worked.

Starts out at 65-70 Psi but bounces 10-15psi either way. Isspro EV2 gauge

 

You definitely should not see that much fluctuation. There is a troubleshooting sheet for the EV2 gauges on the Isspro site here. I downloaded it and found that the voltage in test 4c was out of range. I then called Mike at Isspro and he explained that they have seen a small number of fuel sensors with a manufacturing defect (Isspro doesn't make the fuel sensors, btw) where some sort of seal was slightly off center. The defective sensors typically malfunction shortly after installing.

 

Thanks. Will check it out this wknd.

 

I'm having a similar issue, my gauge would bounce around. I checked all the wiring. I checked the regulator spring and it seems OK. Now it got worse. It will go to 65 lbs on start up and after about 10 seconds jump to the top 100lbs +. If I push accellerator down it will drop to 65 and then slam back up again.

 

Bouncing and high fuel pressure readings can happen from bad injector seals and combustion entering the fuel system.