Did I test this right? or is the fuel pump bad?

[PandaBear]

So I rented an Actron fuel pump diagnostic kit from Autozone to check if my Escort's fuel pressure is good. I connect it to the test port (schrader valve) as tight as I can and see fuel going into the gauge and out of the side clear tubing if I press the relief button. I can only read out 0 to 2 PSI. Does this make sense? I would imagine if the car can go up to 60-70mph, even if burning lean, should demand a fuel pressure that even if not in the 30-45PSI range, it would be at least half that instead of 2PSI.

I also notice that I probably overtighten the schrader adapter, that some of the rubber is deformed and stuck into the test port. If I use a pick to get the rubber out of the test port right after the test, I could see fuel spraying out of it. However I accidentally destroyed some of the rubber on the test port and now it is having a small leak (will fill and spill over to the fuel rail if you pay attention to it) if the ignition is at ON, but the cap for the test port seems to seal it. Is it safe to drive like that or should I replace the test port / fuel rail?

I know I shouldn't tighten the adapter to the port that much to destroy the rubber (and I probably should replace the valve or the fuel rail that the port is on). I'm just trying to see if I was testing the fuel pressure correctly and the fuel pressure is really that low, or did I test it wrong?

Thanks.

 

[mechtech2]

Sounds like a bad connection/interface at the shraeder valve.
Could be a wrong adapter, or parts slightly out of spec.

With the engine off and key on after cycling it a few times, poke a small screwdriver/probe in the shraeder valve and note the stinging in your eyes! Actually, note fuel coming out - it should spray out.

See if the depth of the interface parts match up by eye.

 

[PandaBear]

Yes I did that and it SPRAY out like Windex spraying out of a bottle.

 

[TFB1]

Finger tight on the schrader connections...

Two PSI isn't enough to run the engine at idle so you have a connection issue... They'll run fair at 30 PSI but usually won't have much power under hard acceleration...

 

[Scott_Tucker]

2 PSI isn't even enough for most carburetors

 

[TFB1]

Originally Posted By: Scott_Tucker
2 PSI isn't even enough for most carburetors


True, maybe if the fuel line was around 5/8" to 3/4"...

 

[PandaBear]

I got a warranty replacement on the fuel pressure test kit hardware, and I picked out all the loose rubber on the Schrader valve, then I retest it by hand tightening all the connection.

On the 1st turn of the ignition to ON, fuel pressure reach 15 PSI.
On the 2nd turn of the ignition to ON, fuel pressure reach 32 PSI.
On the 3rd and later turn of the ignition to ON, fuel pressure reach and stay at 38 PSI.

If I understand right, the fuel pressure should be between 30-45PSI. Can I conclude that the fuel pressure is good, so the fuel pump is good (high enough pressure -> high enough flow), so my lean CEL and highway stumbling problem is from something else?

 

[punisher]

Originally Posted By: PandaBear

If I understand right, the fuel pressure should be between 30-45PSI. Can I conclude that the fuel pressure is good, so the fuel pump is good (high enough pressure -> high enough flow), so my lean CEL and highway stumbling problem is from something else?


Now we know what the symptom is.

Fuel pumps can cause that symptom, and cause it intermittently. The way to catch it is to hook up the fuel pressure gauge. Tape the gauge to the corner of the windshield and go for a test drive. When the car acts up, ck the pressure. I, or my helper, drove probably a thousand miles over the years with a fuel pressure gauge hooked up like that. More likely to act up when it is warm. Keep an eye out for any "fuel pump primary" codes just in case a relay/IRCM is acting up.

MAF usually acts up all the time, not intermittently. O2 sensors can drop out intermittently and cause a stumble/rich bog until the PCM goes into FMEM. that will also set a lean/lack of O2 switching code.

From your symptoms and code, I think you are correct to suspect the fuel pump as your primary concern.