Hello

I need some technical help on my 1994 s10 blazer 4x4 with a 4.3L V6 Vin "W" with an auto tranny. I have just recently changed the following items: Fuel filter, spark plugs and wires, motor mounts, transfer case shift motor, Rad and upper and lower hoses and thermostat and the starter.

Last week it died suddenly in traffic, it lost power and brakes. I couldn't get it restarted so I had it towed home. I waited acouple hours and tried to restart it and it started right up. Now it had been tougher to start lately which is why I did the starter a few weeks prior to this.

I immediatly purchased a fuel pressure gaug and tested the fuel pressure which was on key on it was 52psi and start it was about 54psi. once I turned the motor off, it dropped to 20psi with in seconds. I decided that I would replace the Fuel pressure regulator first and then test it and then do the fuel pump.

Well I did the FPR today and as soon as I got it back together I threw the gauge on it and now it shows between 90psi and 100psi. I double checked everything and cant see anything not hooked back up. I double check the FPR to make sure it was right and it is. Also it doesn't hold any psi for any longer. Also the motor only stays on for 30 to 45 seconds before dying and if you give it any gas it stalls immediatly! Please help I don't know what to do.

thanks

 

The regulator isn't functioning properly. That is for sure. It should regulate the pressure to ~60psi.

 

Hello

Yes I figured that.. I was kinda hoping someone would have some ideas on what is causing it.

 

Did everything come apart cleanly and go back together nicely? Maybe something fell into the spider and plugged the regulator? Or a faulty regulator from the get-go?

 

Just rechecked my gauge and it works spot on. It builds up 90psi with just the key on. Is there anyway that the combustion of the engine could create back pressure through a leaking poppet?

I am racking my mind and I come up with nothing. I cant believe that the new FPR is a dud.

Everything came apart smoothly. I was very careful pulling everything apart. A leak in the intake plenum could it cause the problem?

 

With that much going on at once maybe look to the ECM? Of course I learned the lesson long ago that just because a part is new doesn't mean that it's good, especially with electrical parts. Maybe try a FPR from another maker or store. Good Luck!!

 

For pressure to build that high, there has to be a blockage in the system. Compression really cannot get into the fuel system.

The ECM really doesn't have any control over fuel pressure other than telling the pump when to start and stop.

 

I would say either your return line is blocked or your FPR is bad. if you can get a hold of a P-10 tamper proof torx bit you can try turning the pressure down on the FPR. Turn it counter clockwise to decrease the pressure. I got one not long ago that had the pressure set at about 45, turned it to to 65 and it's worked great ever since. So being new doesn't mean anything.

 

I wonder if you messed with the screw in the center of the FPR??? It is a tamper proof as the above poster said, but you can use a tiny screwdriver to snap the pin out of the center of the hole, and a regular torx bit fits in.

When my engine ever gets going again Im totally gonna crank mine up to 65psi and see what happens.

 

Blockage could be an idea, where would it be? Could this mean that the pump is going?

I have the hex drive tool, and no I didn't mess with the FPR, i shouldn't have too. should I? So would that mean that I would have to tear it all apart, turn it alittle put it back, test it and keep doing this until it was set at 60 psi with the key on, but not the motor running?

Should I just source another FPR?

thanks