Is there a Schrader valve on the fuel rail to pressure test the fuel?

[Trucker14]

ive replaced the coil, plug and injector in my 06 expedition Limited. I pulled the O2 sensors to test the cats only to find that didn't solve my hesitation issue at wide open throttle or my misfire under light load. I'm thinking possibly a fuel filter now? I can't get it to throw a code anymore for further assistance. It initially said I had a misfire in cyl 5 so I replaced everything in cyl 5. But it also said a random misfire.

For the life of me I can't figure it out. So I want to do a fuel pressure test at the rail. I don't recall seeing a schrader valve to tap into tho. If no valve, what's the best way to test?

I'm planning on spending the day tomorrow trying to diagnose this. I'll look at and clean the EGR valve. Maybe to a vacuum test. Do a fuel pressure test. Clean the MAF where ever it is on this engine lol. Pull the ignition coil I just replaced and make sure it looks to be making proper contact.

I love the truck but it's definitely turning into a nightmare and my 3 month warranty doesn't cover emissions issues.

 

[Bedrck47]

Not sure if this has been suggested to you But check the Fuel Pump Drivers Module for any signs of corrosion. It is located on the drivers side frame near the spare tire. Good Videos on youtube about this. Your symptoms don't point to this as being a problem but it is worth checking.

 

[Trucker14]

Yea it's been mentioned. I'll take a look at it too. Just doesn't seem like it could be the culprit. But you never know

 

[1955moose]

I know your not going to want to hear this, since you just purchased vehicle, but I would screw a compression tester into #5 cylinder to be sure compression is up to *****. Hopefully it's something simple, but stranger things have happened. Better to know now, so you can re negotiate if possible. Keep us posted with results, let's hope it's simple. The Maf sensor is on the bottom of the air filter tube. If you do a fuel pressure test and your pressure is above specs, you can pretty much rule out filter,pump, wiring, up to the rail. That's the whole idea of the test.


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[docraymund]

You could also check it with a vacuum gauge.

 

[Trucker14]

I know your not going to want to hear this, since you just purchased vehicle, but I would screw a compression tester into #5 cylinder to be sure compression is up to *****. Hopefully it's something simple, but stranger things have happened. Better to know now, so you can re negotiate if possible. Keep us posted with results, let's hope it's simple. The Maf sensor is on the bottom of the air filter tube. If you do a fuel pressure test and your pressure is above specs, you can pretty much rule out filter,pump, wiring, up to the rail. That's the whole idea of the test.


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I don't see a schrader valve to tap into on the fuel rail. Is there one anywhere or how do I check the pressure. And I was definitely planning on doing a compression test on cyl 5. What's an appropriate compression reading on these engines?

 

[Bedrck47]

there should be a Schrader Valve on the passenger side Fuel Rail if not there look on the drivers side or on the lines behind the manifold

 

[1955moose]

Above 135 compression, normally you want to check all to be sure their within balance of each other. Be sure to disconnect spark from other cylinders, when doing test. As Bedrck said check your fuel pump drivers module. They get corroded and cause symptoms like your having. It's located near your spare tire under your vehicle.


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[Trucker14]

• there should be a Schrader Valve on the passenger side Fuel Rail if not there look on the drivers side or on the lines behind the manifold

  I looked thoroughly. I then read online that only some have one. Mine must not.
  
  I also just got a P0430 code indicating catalytic inefficiency in bank 2 which makes sense since bank 2 is where cyl 5 is and that's where it originally showed a misfire.

 

[1955moose]

You can check the catalytic converter many ways, we have posted how on line. Using an infrared gun will tell you if one of yours is clogged. The reading should be 25 to 100 degrees hotter at rear than front. Some muffler shops also do a test by unscrewing o2 sensor, and reading pressure with gauge. As far as your schrader valve, you might have one that has to be teed into with a fuel pressure adapter. Guys do you know if that's true? Anyone have his Year expedition?


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