460 EFI expertise needed. Help Please!
Thread Starter
|
Elder User
Joined: Jan 2000
Posts: 656
Likes: 0
From: Gravel Switch, KY
460 EFI expertise needed. Help Please!
I have a 93 F350 w/460 EFI. Did a tuneup recently and it ran much better, but yesterday it really got to running sick. Mash the pedal to the floor and it wouldn't hardly move, then once it got going it was sluggish and I could feel it surge or miss. Put a pressure gauge on the rail and it shows 30 while idling. Take it for a spin down the road and the higher I rev the engine the more the fuel pressure drops, down into the low 20's. I plugged the return to the tank to try to determine if it was a bad regulator or the pump. Results were the same, starting out at 30 and going down as revs increase. It does hold pressure when shut off. I would think this rules out the pressure regulator. Seems to me this may indicate a bad pump. This is the front tank pump I am playing with but it does more or less the same with the rear pump too. By the way I recently replaced the fuel filter and it seemed to be pretty well plugged. Pumps ain't cheap so I want to cover all the bases before shelling out the cash. Whatcha think? Need advice quick, this is my daily driver.
DannyP
DannyP
Posting Guru
Joined: Jul 2003
Posts: 2,232
Likes: 1
From: Colville, Washington
Originally Posted by Ford_Six
Try the filter again, and see if it makes any difference in the numbers.
Thread Starter
|
Elder User
Joined: Jan 2000
Posts: 656
Likes: 0
From: Gravel Switch, KY
Success!!! 
I replaced the rear pump and now it has about 30-32 at idle and the pressure increases to around 40 when accelerating at WOT. With the old pump pressure would drop as rpms increased. Runs much smoother now. The front pump still behaves the same as previous so obviously it needs to be replaced too. At $136 a copy I think I'll wait until next week to buy the front. I always figured if the pump ran it was OK, guess not.
Thanks Guys
DannyP
I replaced the rear pump and now it has about 30-32 at idle and the pressure increases to around 40 when accelerating at WOT. With the old pump pressure would drop as rpms increased. Runs much smoother now. The front pump still behaves the same as previous so obviously it needs to be replaced too. At $136 a copy I think I'll wait until next week to buy the front. I always figured if the pump ran it was OK, guess not.
Thanks Guys
DannyP
Thread Starter
|
Elder User
Joined: Jan 2000
Posts: 656
Likes: 0
From: Gravel Switch, KY
Originally Posted by Putt
Interesting!!! I guess they can both fail at the same time!!!!!:-)
Glad you got it on the road.
Glad you got it on the road.
DannyP
Thread Starter
|
Elder User
Joined: Jan 2000
Posts: 656
Likes: 0
From: Gravel Switch, KY
Boy, Have I got a new problem now. The truck has twice as much power as it had before, but it is also using twice the gas. I went from getting 13.5 mpg prior to installation of the new fuel pump to 7.5 mpg now. Pulling codes show I need an oxygen sensor so I bought one, hopefully it will help get me back up to 10 at least.
DannyP
DannyP
Trending Topics
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Thread Starter
|
Elder User
Joined: Jan 2000
Posts: 656
Likes: 0
From: Gravel Switch, KY
I'll admit to a little leadfooting, but not enough to account for that difference. It actually takes less pedal now to get moving and stay moving. Installed new oxygen sensor last night and the code 41 (oxy always lean) went away. Keeping my fingers crossed...
DannyP
DannyP