Misfiring and not accelerating

Tiny
DILDON
  • MEMBER
  • 1992 FORD E-SERIES VAN
  • 5.8L
  • V8
  • 2WD
  • AUTOMATIC
  • 180,000 MILES
Truck was missing horribly and was wet out thought might be misfiring caused by moisture. Tuned up, wires, plugs, cap, button. Started still missed. Replaced fuel pump and fuel regulator. Will start good throttle response but slowly starts to miss and will not accelerate. Turn off restart and accelerates fine but shortly starts to miss and will not accelerate. Checked pressure at rail 50 lbs when you try to accelerate pressure would fall all the way down to 5 lbs. Is new pump bad or should I be looking somewhere else?
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Sunday, February 16th, 2020 AT 10:07 PM

10 Replies

Tiny
JOETECHPRO
  • EXPERT
Hey DILDON,

Did you also replace the fuel filter?

Sounds like you may have already but wanted to confirm.

The instructions for replacing the filter are below.

I would advise when you have the the old filter removed try blowing back through in reverse direction into a container and seeing how contaminated the fuel entering was.

How did the inside of the tank look when you replaced the pump?

Regards, Joe
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Sunday, February 16th, 2020 AT 10:39 PM
Tiny
SCGRANTURISMO
  • EXPERT
Hello,

This sounds like you could have a faulty fuel pressure regulator. The fuel pressure on Ford vehicles should be 39.15 lbs. At the fuel rail. What usually happens when the fuel pressure regulator fails is the diaphragm inside fails and allows fuel to leak into the vacuum line on top. In the diagrams down below I have included the directions for the removal and installation of the fuel pressure regulator for your vehicle as well as the Original Equipment Manufacturer[OEM] part number for your reference. Please go through these guides and get back to us with how everything turns out.

Thanks,
Alex
2CarPros
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Sunday, February 16th, 2020 AT 10:56 PM
Tiny
DILDON
  • MEMBER
Replaced fuel regulator and installed new fuel pump plus complete tune up. But it still acts and sounds like it s running out of gas.
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Monday, February 17th, 2020 AT 4:05 AM
Tiny
JOETECHPRO
  • EXPERT
Hey DILDON,

To confirm you have replaced the fuel filter?

It sounds like you have a restriction in the fuel system.

I would ensure that you haven't crushed or kinked any fuel lines when installing the pump.

Also can you check the vacuum line to the pressure regulator and make sure it is in good condition.

What did it look like inside the tank when you replaced the fuel pump?

Regards, Joe
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Monday, February 17th, 2020 AT 7:58 AM
Tiny
DILDON
  • MEMBER
Not bad checked pressure at rail it was around 40 but if you accelerate it would drop down to below 10.
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Monday, February 17th, 2020 AT 8:19 AM
Tiny
JOETECHPRO
  • EXPERT
Hey DILDON,

Let us know about the fuel filter condition, remove the filter and blow back through to check for dirt.

Recheck the fuel lines and let us know what you find.

Regards, Joe
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Monday, February 17th, 2020 AT 8:35 AM
Tiny
DILDON
  • MEMBER
New filter, but will blow lines out and install another new filter.
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Monday, February 17th, 2020 AT 8:40 AM
Tiny
SCGRANTURISMO
  • EXPERT
Hello again,

After you install another fuel filter please check the fuel pressure regulator and get back to us.

Thanks,
Alex
2CarPros
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Monday, February 17th, 2020 AT 12:13 PM
Tiny
DILDON
  • MEMBER
Fixed ended up being a bad new after market fuel pump.
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Tuesday, February 18th, 2020 AT 4:11 PM
Tiny
JOETECHPRO
  • EXPERT
Hey DILDON,

Great work, thank you for updating us with the fix!

Aftermarket parts can cause no end of frustration. Glad you got it figured out.

Thank you for using 2CcarPros.

Regards, Joe
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Tuesday, February 18th, 2020 AT 8:24 PM

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