Fuel System problem?
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New User
Joined: Aug 2013
Posts: 13
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From: Central Interior, BC
Fuel System problem?
Hey Guys!
As a brief intro I don't even qualify as a beginner mechanic. But, I live in a rural area, naturally curious, and willing to learn.
My 1991 F250 manual, 4x4 is a recent purchase (200,000km). Seemed to be in ok shape. Returning from a recent 140 km RT all of a sudden I lost power, but slowly. Full fuel tank. Gauges were good/checked fluids and let sit for a few minutes. Started up and went for a few more kilometers and the same experience. No power. Step 1: changed fuel filter on frame near front fuel tank. Good! Dirty. Worked fine for ~ 60 days. Then same problem. Took off the new fuel filter. Seemed clean and no debris.
1) Any first basic trouble shooting ideas?
2) Are there any other smaller/finer fuel filters closer to the engine?
-----
Curious:
A) Looks like there is a separate gas line from each fuel tank; didn't see a junction; how does that work with only 1 single line fuel filter?
B) Following the gas line from the fuel filter to just below the engine, but still on the frame there is what looks like a 2 inch plastic square with the fuel line entering and exiting. Is this a sensor of some sort?
Russ
As a brief intro I don't even qualify as a beginner mechanic. But, I live in a rural area, naturally curious, and willing to learn.
My 1991 F250 manual, 4x4 is a recent purchase (200,000km). Seemed to be in ok shape. Returning from a recent 140 km RT all of a sudden I lost power, but slowly. Full fuel tank. Gauges were good/checked fluids and let sit for a few minutes. Started up and went for a few more kilometers and the same experience. No power. Step 1: changed fuel filter on frame near front fuel tank. Good! Dirty. Worked fine for ~ 60 days. Then same problem. Took off the new fuel filter. Seemed clean and no debris.
1) Any first basic trouble shooting ideas?
2) Are there any other smaller/finer fuel filters closer to the engine?
-----
Curious:
A) Looks like there is a separate gas line from each fuel tank; didn't see a junction; how does that work with only 1 single line fuel filter?
B) Following the gas line from the fuel filter to just below the engine, but still on the frame there is what looks like a 2 inch plastic square with the fuel line entering and exiting. Is this a sensor of some sort?
Russ
Post Fiend
Joined: Oct 2003
Posts: 9,176
Likes: 4
From: Western Central NV
You need to check fuel pressure. It kind of sounds like you may have fuel pump issues. But I'm just guessing. You need to check fuel pressure.
Here is a website that might help. Fuel Injection Technical Library
Craig
Here is a website that might help. Fuel Injection Technical Library
Craig
Post Fiend
Joined: Oct 2003
Posts: 9,176
Likes: 4
From: Western Central NV
You need to check fuel pressure. It kind of sounds like you may have fuel pump issues. But I'm just guessing. You need to check fuel pressure.
Here is a website that might help. Fuel Injection Technical Library
Craig
Here is a website that might help. Fuel Injection Technical Library
Craig
Lead Driver
Joined: Feb 2003
Posts: 8,140
Likes: 4
From: Oak Harbor, OH
How was the maintenance before you go it? Did they do tune-ups at the proper time? This sounds like a failing catalytic converter to me. It COULD be a fuel system issue as well, either a weak pump or bad electrical connection. Is it the same hot or cold?
Thread Starter
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New User
Joined: Aug 2013
Posts: 13
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From: Central Interior, BC
catalytic converter
Hey Pfogle,
My sense is the maintenance was performed regularly...it was the wife's truck.
I intend to check the fuel pressure... Have, only experienced the condition after the truck has been operating for 20 min to 1 hour.
But your idea of "a failing catalytic converter" is also curious. Any basic ways to check that out?
Russ
My sense is the maintenance was performed regularly...it was the wife's truck.
I intend to check the fuel pressure... Have, only experienced the condition after the truck has been operating for 20 min to 1 hour. But your idea of "a failing catalytic converter" is also curious. Any basic ways to check that out?
Russ
Fleet Owner
Joined: Oct 2005
Posts: 20,780
Likes: 1,746
From: Kentucky
A failing converter will not correct itself when the engine cools down. I would lean more towards the much more heat related failure attributed to the Ignition Control Module (ICM/TFI) mounted on the distributor or the stator (PIP) inside the distributor.
Then there is always the possibility of a failing fuel pump. The OP's 1991 should have high pressure pumps in each tank, so switching from one tank or the other should determine if it is a fuel pressure issue.
For reference:
Fuel Injection Technical Library » Stator (RPM)
Fuel Injection Technical Library » Thick Film Ignition (TFI)
Then there is always the possibility of a failing fuel pump. The OP's 1991 should have high pressure pumps in each tank, so switching from one tank or the other should determine if it is a fuel pressure issue.
For reference:
Fuel Injection Technical Library » Stator (RPM)
Fuel Injection Technical Library » Thick Film Ignition (TFI)
Thread Starter
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New User
Joined: Aug 2013
Posts: 13
Likes: 0
From: Central Interior, BC
Question about fuel pumps
Hey rla,
Thanks for the thoughts on the ICM and PIP.
Are the 1 pump each in the fuel tanks, auxiliary units to a master, or are they the primary units?
Russ
Thanks for the thoughts on the ICM and PIP.
Are the 1 pump each in the fuel tanks, auxiliary units to a master, or are they the primary units?
Russ
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New User
Joined: Aug 2013
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From: Central Interior, BC
As weird as it was...
Pfogle looks like you were on the money. Seems the catalytic converter had corroded to the point of pieces...or so it was told to me. Does that make sense?
Thanks everyone!
Thanks everyone!
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