I installed new EV-2 gauges recently and all went well until I noticed that occasionally, the fuel pressure gauge will jump from 63-64 to 85+ and sit there.
A restart will sometimes correct the problem. I have a RR, FRx. (early one).
Any thoughts???????

 

It could be either the fuel pressure sender or a sticking FPR poppet valve.

If it is the poppet valve you need to rebiuld the FPR. Kit availble at Dieselorings FPR Rebuild Kit.

If you have to rebuild FPR I suggest you install the Dieseloring Billet FPR Housing.

 

I have the same gauge and also an Frx. I just installed the Frx last week but I haven't noticed anything like what you said. I would rig up a temporary switch to momentarily disconnect the EV-2 when it happens. This way you will know if it is the gauge or the FP is really that high.

 

I have a pretty new FPR housing from RR. One of the early ones that is shimmed.
Of course, that does not mean it isn't malfunctioning.
The weird thing is that it doesn't do it all the time.

 

The poppet valve and poppet valve guide are actually in the fuel bowl and not part of the FPR housing. Take a look at the FPR rebuild kit link.

 

Thanks Payson...Sorry for the late reply. I was off chasing Bambi. I'll get a kit and start there.

 

I think it might be good to rebuild the FPR with the kit that Robin posted. I experienced similar symptoms and it turned out to be the FPR.

 

Will do...............

 

Well, I rebuilt the FPR and hopefully this will stop the pressure spikes. However, I am still getting 75# of pressure. I have the first generation RiffRaff FRx which is shimmed to mod the pressure.
After the rebuild I was getting 75-80 PSI at idle. I talked to Clay and he suggested putting the old spring back in instead of the new one that came with the kit. I did this and I am still getting 75 PSI. The old spring is visibly smaller and shorter than the new stock replacement. The pressure fluctuates at idle as well. Just a few pounds, but it still moves up and down.
Any thoughts or suggestions??????

 

Patrick, was getting the same reading with my first gen FRx, but it didnt come with a different spring. I usedthe stock one, and all day long, saw 75psi, then spiked to 80-ish. Wasnt happy with that, so took FPR apart, wet-sanded the poppet, re-installed with cutting 1 turn of the spring off, now it sits at 62psi...woohoo.

 

Well, as the guts are new... I think I will try cutting a turn off the spring. That just might be the ticket.
Thanks

 

This may seem like a no brainer, but why would 62 psi be better than 75?

 

For me, i came to the conclusion, that the higher the psi (fuel), the noisierthe injectors were, which ultimately was conclusive. I'm not saying yours or anyone elses truck will do the same, but for me, it worked and the "knock' is all but deminished...very satisfied with it.

 

I wonder if mine would be quieter if I went with the softest spring from the FrX kit....

 

I'll do anything for less injector knock.