85 F250 fuel system, how does this work??
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Post Fiend
Joined: Jan 2000
Posts: 5,330
Likes: 17
From: Dryden, ON, Canada
85 F250 fuel system, how does this work??
I was working on my F250 today, and, I noticed a sticker on the rad support stating that the truck has a fuel pump inertia cut off swith. How exactly does this work?? The truck is carburated, and, the only other 80-86 Ford I've dealt with that dual tanks was an 84 witha 351W, and, it didn't have such a thing. Does my F250 have low pressure in tank pumps that feed the mech. pump on the engine(if it has one) or some other such thing?
I was not expecting to run into anything like this.
Evan
85 F250 HD XLT Lariat 4x4:
460/T19/NP 208(I think) 3.55 geared Full Floater 10.25 and a Dana 50 TTB
1982 F100 SWB
300 HD: NP 435/2.75 geared 9"
78 F150, 351M/C6, soon to be repowered with a 400
I was not expecting to run into anything like this.
Evan
85 F250 HD XLT Lariat 4x4:
460/T19/NP 208(I think) 3.55 geared Full Floater 10.25 and a Dana 50 TTB
1982 F100 SWB
300 HD: NP 435/2.75 geared 9"
78 F150, 351M/C6, soon to be repowered with a 400
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
85 F250 fuel system, how does this work??
Your guess is probably right about the electric pumps in the tanks. There are many variations in the fuel systems in these trucks, but if it says you have a fuel cutoff switch, then you must have electric fuel pumps somewhere. The fuel safety cutoff switch is a switch inline with the wire sending voltage to the pump(s). It has a pendulum inside it, which if you are in an accident will swing up and trip the switch, stopping current to the fuel pump. If this happens, the switch will need to be manually reset to get the pumps going again.
Senior User
Joined: May 2002
Posts: 484
Likes: 1
From: Garden Grove USA
85 F250 fuel system, how does this work??
The 460 cid came with in-tank fuel pumps. There is no mechanical pump on the engine. As stated, the inertia switch is in the case of an accident. There is also a low oil pressure switch wich is bypassed when starting the engine, then when the engine starts and builds up oil pressure, the pumps kick on and your off and running. These do go bad, or in my case connections go bad and cause all sorts of problems.
New User
Joined: Aug 2002
Posts: 3
Likes: 0
85 F250 fuel system, how does this work??
I have been working on my Ford for the pastfour days.
It to has a problem with fuel.But I did find the cut off switch
the one on this 1989 F250 it is down by the clutch pedal on
the fire wall inside the cab.If the fuel switch is set off the red button pops up and you will have to reset it.
It to has a problem with fuel.But I did find the cut off switch
the one on this 1989 F250 it is down by the clutch pedal on
the fire wall inside the cab.If the fuel switch is set off the red button pops up and you will have to reset it.
New User
Joined: Oct 2007
Posts: 1
Likes: 0
i am having fuel delivery problems with my 1989 f250 how do i test the tank pumps to insure that they are working without dropping the tanks?
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Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
Look on the engine and find the fuel rail that feeds all the injectors. Somewhere on this fuel rail there will be a test port. If you take the cap off, it will look like a valve on a tire. A fuel pressure gauge can be put on this port and it will measure the fuel pressure.
If you do not want to buy a fuel pressure gauge, what I did was take guts out of the valve like you do on a tire, and then slipped a hose over the port with a hose clamp. I then used a regular gauge to measure the pressure.
Be careful messing with this test port, and use a rag around it. If you press on the center, instead of air coming out like a tire, fuel will squirt out.
If you do not want to buy a fuel pressure gauge, what I did was take guts out of the valve like you do on a tire, and then slipped a hose over the port with a hose clamp. I then used a regular gauge to measure the pressure.
Be careful messing with this test port, and use a rag around it. If you press on the center, instead of air coming out like a tire, fuel will squirt out.
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