down on power
Thread Starter
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Freshman User
Joined: Nov 2003
Posts: 36
Likes: 0
From: West Virginia
down on power
hello all,
my 94 F150 4WD 5.0 5 speed is beginning to loose power on certain hills on interstate, i asked what i consider to be a reliable source, and he said that it may be time for some head work (ie valve or valvespring issues) which i can understand at 168,000. i was wondering if anyone had experienced similar problems. and also, if this is the issue, i would be very interested in recamming the old girl, as i do trail drive her some, am running catback 3 inch with a 40 series delta flow, and fairly agressive tires (N78-15 bias buckshot wide mudders). does anyone here have a good low end combo using stock heads and pistons, am open to fuel system upgrades, and am going to get headers just as soon as i get tax return.
thanks for the help,
Daniel
my 94 F150 4WD 5.0 5 speed is beginning to loose power on certain hills on interstate, i asked what i consider to be a reliable source, and he said that it may be time for some head work (ie valve or valvespring issues) which i can understand at 168,000. i was wondering if anyone had experienced similar problems. and also, if this is the issue, i would be very interested in recamming the old girl, as i do trail drive her some, am running catback 3 inch with a 40 series delta flow, and fairly agressive tires (N78-15 bias buckshot wide mudders). does anyone here have a good low end combo using stock heads and pistons, am open to fuel system upgrades, and am going to get headers just as soon as i get tax return.
thanks for the help,
Daniel
Post Fiend
Joined: Oct 2003
Posts: 6,214
Likes: 13
From: New Jersey
loss of power can be realized from several issues.
Valves sticking open (even a little), weak valve springs, worn cam lobes, bent pushrods, lifters that dont "pump up" of hydraulic, etc, all contribute to less air/fuel getting into the cylinder, or air/fuel not staying in the cylinder to be burned.
Other possibilities include a stuck injector (or bad wiring to said injector) which prevents fuel from getting in. Also, a warn-out plug will do this too, though a stuck injector/burnt plug would be fairly obvious because the engine would be running on less than eight (or six) cylinders depending on the motor, therefore run rougher than you're used to.
Another possibility sad to say might be rings. Too low of a compression (i.e. too much blow-by) would result in reduced power. YOur effective compression ratio is reduced because some of the mixture when being compressed, works past the rings into the crank/oilpan area of the engine, so you're now adding that volume to the cylinder volume. Easy to check, look at the oil. If its disgusting (meaning you have gas in it) the you know the rings need some R&R.
On a humorous note, a friend of mine a few years ago had one cylinder on a town car not working right, and he replaced the injector, the plug, the wire, etc etc etc and it was still only running on what seemed to be 7 cylinders.
Turned out this used town car didn't have an air filter, so a mouse managed to climb through the air intake, the intake box, all the way into the intake, and got sucked into one of the intake runners.
Though, I highly doubt that will be what you find. But hope you got a chuckle out of it anyway.
Valves sticking open (even a little), weak valve springs, worn cam lobes, bent pushrods, lifters that dont "pump up" of hydraulic, etc, all contribute to less air/fuel getting into the cylinder, or air/fuel not staying in the cylinder to be burned.
Other possibilities include a stuck injector (or bad wiring to said injector) which prevents fuel from getting in. Also, a warn-out plug will do this too, though a stuck injector/burnt plug would be fairly obvious because the engine would be running on less than eight (or six) cylinders depending on the motor, therefore run rougher than you're used to.
Another possibility sad to say might be rings. Too low of a compression (i.e. too much blow-by) would result in reduced power. YOur effective compression ratio is reduced because some of the mixture when being compressed, works past the rings into the crank/oilpan area of the engine, so you're now adding that volume to the cylinder volume. Easy to check, look at the oil. If its disgusting (meaning you have gas in it) the you know the rings need some R&R.
On a humorous note, a friend of mine a few years ago had one cylinder on a town car not working right, and he replaced the injector, the plug, the wire, etc etc etc and it was still only running on what seemed to be 7 cylinders.
Turned out this used town car didn't have an air filter, so a mouse managed to climb through the air intake, the intake box, all the way into the intake, and got sucked into one of the intake runners.
Though, I highly doubt that will be what you find. But hope you got a chuckle out of it anyway.
Thread Starter
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Freshman User
Joined: Nov 2003
Posts: 36
Likes: 0
From: West Virginia
compression is good, checked that already, replaced plugs, wires, cap, and rotor. checked injectors, cleaned entire fuel system, also pulled throttle body and cleaned it. im an auto tech student, so this sort of thing is kinda by area. im sayin it is a valvetrain issue, that or gremblins?
Daniel
Daniel
