[ch215]

Hi guys,

So my car broke down at the middle of an intersection yesterday. I was idling at a light and it just turned off & would not start back up.

I changed the opti recently and I'm thinking this may be a fuel issue. Just to be sure, I replaced the fuel filter - Still won't start. I rented a fuel pressure gauge from the local auto parts store and I'm attempting to check my pressure for the first time.

I'm having a tough time locating my schrader valve. All the articles I came across said on 93's, it was on the passenger side fuel rail. I noticed something that looks similar (with no cap) on my drivers side rail. Is this the correct spot to check for fuel pressure?

Also, any tips for a newbie on the procedure? I'm hoping this test will confirm it's the fuel pump so I can begin tackling it. When I turn the key, I can hear the fuel pump engage. However, after I replaced the fuel filter & primed the car a few times - the pump seemed to become much weaker sounding after the second and third key turns.

Thank you so much in advance

 

[cocobolo95]

Download the 93 factory service manual in the 4th gen section. Look for thread titled "GM service manuals". In volume 1 page 6E3-A-32 there is an illustration that shows where the fuel pressure test port is. From the pic, it looks like it's on the driver side.

Also appears to be in metal line.

 

[ch215]

Thanks for the quick response. Yes it appears to be the correct spot.

As far as diagnosing the problem, all of the articles I come across indicate to check the fuel pressure while driving. The problem is, the car will not stay started.

When I turn the key, it stays at 0. Although I did just change the fuel filter and relieved the pressure with the gas cap.

Any ideas on how I can diagnose this with the car not running?

Thank you in advance

 

[cocobolo95]

When you turn the ignition switch to on, the fuel pump should prime the system to 41 ps1 or over. You don't have to be running to check initial fuel pressure. It is often times good to check fuel pressure while under different running conditions, but since your car won't run, that's impossible at the moment.

But the fact of you having 0 pressure at key on prime says either pump isn't actually pumping fuel, or pressure regulator is stuck fully open and all fuel is returning to tank.

 

[ch215]

cocobolo95: Very valuable information sir. Thank you for responding.

If the pressure regulator is stuck open, is there a way for me to identify it? I know it's kind of tucked in back there.

 

[cocobolo95]

You might be able to hear the fuel running back to the tank with a stethoscope, but opening the return line and seeing fuel come out is the best way. Of course use a catch can for the fuel. If no fuel comes out at key on prime, safe bet that fuel pump has cashed it's chips in, or fuel pickup hose, in tank has come off or has a hole. Either way it's take the fuel pump out of tank time.