My truck stalls out on hills

JR Wood

New Member
I don't know if this is the right forum for this. My f-350 keeps stalling out on hills or whenever there is a load on it it is a big flatbed.1987 7.1 liter engine. It runs fine on flat surfaces. anybody know anything about carburetor problems?
 

Douglas Hicks

New Member
Fuel filter or fuel pump or crud in the tank? going uphill requires more fuel.

Douglas Hicks
General Fire Equipment Co of Eastern Oregon, Inc
 

Aplus

New Member
Loss of power under load is likely a fuel or ignition problem.

Without more information, it would be hard to help you any further with a diagnosis.
 

ron

New Member
sounds

like a computer problem. Not sending out the right info to adjust air fuel mixture.
I would take it to a diagnostic testing garage. It will save you a lot of headaches.
Slight chance it could be a transmission problem.
 

Larry L.

PWN TEAM - Moderator Emeritus
I agree with Tony,sounds like a fuel filter problem...if it's a diesel and when going up hill or pulling a load if it smokes alot when losing power it has water in the fuel.
 

JR Wood

New Member
Sorry it is a 7.5 (460) engine and it is not a diesel. I rebuilt the carb today and it does the same thing. I already checked the tanks for crud and changed the filters. I also put isopropyl in to absorb any water. I am stumped. I don't think this thing has an onboard computer. I am going to change all the vacuum hoses tomorrow and see if that does it. Next the fuel pumps!!!!! Good thing that the bed has trap doors so I can get at the tanks easily!
 

Larry L.

PWN TEAM - Moderator Emeritus
Have you checked the firing,the vac-ad-vance would not be working,sometimes it will rust alittle down in the distributor and the vacuum cann't pull it open when you need more fire power.
 

Chuck Richard

New Member
had loss of power in my truck and it turned out my catalytic converter had melted and came apart. sometimes it would block exhaust flow and cause severe power loss. have you checked this?
 

ron

New Member
air,fire,and fuel

one of these 3 things is wrong. Either not enuff os of one of them or not getting them at the right time.
You should have a electronic module on the fire wall or wheelwell.
When was the last set of wires and plugs put in?
On hills the gas sloshes back and maybe the sending unit is not picking up the fuel.
need more detail about what it's doing when it starts to die.
Just quit,chugging,is it after a steady pull up a hill,will it do it if you parked on a hill and reved up the engine?
 

Aplus

New Member
If the issue of a fuel problem is ruled out, I would look at ignition next.

Try replacing the distributor cap, rotor, plug wires and plugs. A crack in the cap, or a worn spark plug wire that has rubbed itself on something will cause the problems you mention.

Could possibly be a coil problem, but I would do the above maint items first, which probably need to be done anyway, if it hasn't been done in the last 40k miles or so.
 

Chuck Richard

New Member
is the truck popping and sputtering,is it misfiring,is it cutting off completely, or is it just losing power?Answering these ?s will help us narrow down the problem. Thanks, i hope we can help.
 

Aplus

New Member
Justin,
An 02 sensor failure will set a code, and cause the check engine light to illuminate. Sometimes the engine will run a little rich, and if it has a catalytic convertor, will cause a sulfer rotten egg smell.

It is also possible that in 1987, 1 ton & up trucks could have been exempted from some of the smog rules as cars, and may not have the same smog devices installed.

A faulty 02 sensor usually does not cause significant performance problems.
 

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