To much fuel pressure

Hey guys im back again lol. Got some more work done on the Riv in class tonight. I was checking fuel pressure and with key on engine running im seeing like 65 PSI! Which is crazy cause 47 is the high end that it should be. Any ideas??

That is high for idle. Have you replaced the fuel pump or fuel pressure regulator?

The pump is new.

Hmm. Did you wire up the pump using the exact same wiring, like the old one was? I wonder if there's some way the PCM can alter the voltage to control PSI from the pump.

If your reading the fuel pressure from the fitting on the fuel rail, then you are reading the pressure that is down stream of the fuel pressure regulator.
So the pressure regulator is what is controlling this pressure.
If you want to read fuel pressure from the pump you will need the correct adapter to hook into the quick disconnect fitting on top of the SC.

Also, are you sure about the accuracy of your gauge.?
Do you have someone you can borrow from and compare.?

Would it be safe to assume he doesn't need to read pressure directly from the pump? All we really need to know is what the fuel injectors see, right? If the pressure is high after the regulator, it surely would not be lower before it.

AA wrote:

Would it be safe to assume he doesn't need to read pressure directly from the pump? All we really need to know is what the fuel injectors see, right? If the pressure is high after the regulator, it surely would not be lower before it.

That is exactly what I was trying to point out, is that he's presumably reading pressure downstream of the regulator which would mean that the Fuel Pressure Regulator is bad and no need to condemn the pump.
It is clearly working fine and putting out plenty of pressure based on what he is seeing for gauge readings.

I am using a gauge from the school so I think we got another one I can try that one too. I am testing from fitting on the fuel rail ur right bout that. Another thing I will add, with the gauge hooked up key on engine off the pressure didn't hold steady it came up then fell off.

How much is a fuel pressure regulator? Maybe replace that and see if your pressure issues go away.

Its 70 bucks. I think im gonna get it cause it obviously needs fixed.

AA I just seen your post about the wiring. I am not shur about that. I do kno the guys that does my wiring found a bunch of crap wires going into the ECm but that has been fixed.

Before you replace it, does anyone know if the voltage to the fuel pump is fixed, or is it varied by the PCM based on fuel pressure needs?

You should be checking fuel pressure at the fitting on the fuel rail, with the vacuum line to the pressure regulator disconnected.

It is my understanding that the FP voltage is floating, controlled by the PCM, but not sure about '95s.

I see and when I unplugged the vaccum line from it it was about 50 and bouncy. I just ordered a regulator from rock auto for 36 bucks should I cancel?? Should mentioned my instructor had us unplug the vac line and test lol.

Sounds like you don't need any parts. What symptom are you troubleshooting that made you suspect fuel pressure?

Well before the wiring was redone it was a no start. Now it starts most of the time it just takes a few. I pulled some codes last night one was MAF low and one was TP low. So I need to test those sensors next. I did a fuel volume test, did a resistance check on injectors..which that wont tell me flow but I figured the volume test came out good so.

What happens to your FP when you shut the car off? How quickly does it bleed down? How quickly does the pressure build when you first turn on the key (before trying to start)? If you let the fuel pressure build, does it start on the first try?

Well we did do a key on engine off. The pressure came up then bled down gradually