Fuel Pressure Regulator, question??? Options

[76-914]

Is it recommended to change out the fuel PRV (pressure reducing valve) after installing a fuel pump. I ask because I notice an appx 2psi gain when I installed the new Bosche OEM fuel pump. I installed a new pump after the engine quit and I noticed the pressure at 15 psi. The next am it started and pressure was again at 30psi but I wasn't taking any chances so I replaced it. Now, I wonder if I miss diagnosed it and the fuel PRV may have been the culprit. Change out or re adjust it? Experienced advice is greatly appreciated. Thx in advance!

[realred914]

Is it recommended to change out the fuel PRV (pressure reducing valve) after installing a fuel pump. I ask because I notice an appx 2psi gain when I installed the new Bosche OEM fuel pump. I installed a new pump after the engine quit and I noticed the pressure at 15 psi. The next am it started and pressure was again at 30psi but I wasn't taking any chances so I replaced it. Now, I wonder if I miss diagnosed it and the fuel PRV may have been the culprit. Change out or re adjust it? Experienced advice is greatly appreciated. Thx in advance!

drop in pressure could be from a clogged line pinched hose, or clogged filter also. junk in the gas tank (like an old rag) could glog the outlet also, then move around and not glog it latter.

then again, a bad pump may intermitantly loss pressure (maybe dirt in pump?)

do you constantly have a pressure gage to read the pressure? if so, i'd keep running it and see if you experience a drop again.

idrt in a regulator could also cuase intermittant pressure changes but i would think it would result in a high pressure not a low pressure (dirt preventing the port to close enough to regulate) if the diaphram was torn, the regulator would not self heal.

keep an eye on it for a while and see if the problem is gone or not. at this point I would not start swaping any more parts until your sure it is still bad. if still bad start with the filter and looking for pinched hoses under the tank as that is easy and cheap to fix,

[Mike Bellis]

I use a regulator on every fuel system I build. A change in pressure will effect the tuning and drivability of the car. On the system I'm working on now, I have a 50 psi pump for a 15 psi EFI system. The type I use in an Aeromotive bypass style. In my case, without the bypass the pump would over pressurize the line bogging down the pump. If you use carbs, 2 psi is enough to blow past the needle valve and flood the system. If you are only adjusting for 2-3 psi, a bypass is not needed.



I also run a pressure gauge on the regulator and on the fuel rail.

[76-914]

OK, I should have been more descriptive. It is the stock 2.0 DJet sys. The tank is cleaner than a new born baby's ass. The pressure just climbed a bit after the new pump was installed. The stock PRV is still in place and appears to be working as I haven't noticed any pressure fluctuations in the cockpit. Just the modest increase I mentioned above. OK to leave the old PRV and re adjust or is this a precursor to PRV failure?

[realred914]

OK, I should have been more descriptive. It is the stock 2.0 DJet sys. The tank is cleaner than a new born baby's ass. The pressure just climbed a bit after the new pump was installed. The stock PRV is still in place and appears to be working as I haven't noticed any pressure fluctuations in the cockpit. Just the modest increase I mentioned above. OK to leave the old PRV and re adjust or is this a precursor to PRV failure?

old dying pump maybe could not make the minimal pressure as it died first it was 2 psi too low, then 15 psi too low at some point it got so low the car would nto run so that is why you saw the drop. if it is stable with new pump, I'd not worry no more.