fuel pressure problem?

[AHutchison]

I have a di pricol fuel pressure gauge and when i start it up some mornings it will read 7-7. 5 psi. Then there are mornings that i start it up and it will read 5. 5-6 psi and sometimes almost into the red on the gauge. This all occurs at an idle. Is this a problem with the gauge, isolator or is this a lift pump problem. The only mod that is on the truck now is a powermax cr. Do I need to replace this with a pusher pump to correct this problem? I'm confused here of what is going on here with the pressure.

 

[mattymac]

I have the same symptoms with my Autometer, but my readings are consistant with the temp of the motor. When its cold it reads low, warm it can read up to 2 lbs higher.

 

[Jengle]

Reading the same as mine. Funny, I have the TST PMCR too. Sucks that pressure right down, on 5 and up, don't it? Seems mine is keyed to temperature. When its cooler out or cold, it reads a little lower than when the temp is warmer. Getting ready to put a fuel pump on, as soon as I can decide which one.

 

[lmills]

Are you sure you all aren't seeing the grid heaters cycling when you first fire up the motor? They will cause a slightly lower fuel pressure becuase of the excessive current the heaters draw

 

[mattymac]

It just seems to stay low, doesnt cycle, plus its not cold right now where I live so my heaters dont cycle stays right at 14 volts after start up.

 

[lmills]

Ahh OK, I was just curious. We've been getting down into the 40's here lately and when the heaters are cycling I can see the fuel pressure drop a little.

 

[AHutchison]

the heaters are coming on when starting up, but the gauge reads the same even though the engine is at normal operating temps. I tried putting the pwermax on 0/0 and the same readings keep happening. I'm just wondering if there is something that I am overlooking here.