Well exactly what it says is what i am experiencing. Overall my truck runs like a champ, starting to knock a little but its because i dog it which i shouldn't as much but i know it can handle it and i enjoy having some fun. My biggest concern right now is on my fuel delivery.

The problem i am a bit perturbed about. For one i cannot start my engine off the rear tank unless i basically try to start it than start it again or pump the pedal a little, i figure a weak pump. Off the front pump it fires right up!

The thing that i do not understand is why on the front pump my motor won't rev past 3.5k if i am lucky but pushes well into 4k almost 5k on the rear tank?? and has power through the entire band. Off the line in the front tank it puts me back in my seat but off the line in the rear its lie a snail but gradually builds power and as it hits 3k its like a turbo kicks in. I can honestly take off on my front tank and have pedal to the metal and as i get into 2.5k on the front tank i can switch to my rear tank and have the same power i had off the start. It is insane, don't get me wrong i love it but it is just odd. Also with the rear tank i am getting HORRIBLE in town mileage. roughly 200 to a tank which is 19 gallons of mixed highway and town; highway being 80-110 miles of that.


Any ideas besides a weak fuel pump? I have a 1995 EFI all stock 300 with an E4OD

 

Do you have separate filters or is there only one? If separate maybe the front one is plugged if not maybe the "sock" in the front tank is clogged. As far as the hard start on the rear tank I am uncertain of the in tank system for yours but a friend of mine had a motor home and was having hard start and lack of power issues and he found there was a piece of hose in the tank which was cracked. It was just dumping fuel back into the tank.

Jim

 

As far as i know i only have one which is on the outside of both tanks which was replaced. I had gotten this truck 3 years ago and have put on less than 15k miles and did a tune up about 2 years ago so filter and all that i know of has been done. I have never taken off a fuel tank before because my other vehicles have all had external pumps(so much easier!!!). Because the lack of room underneath and jack not working i all have to take the bed of my truck off to look at anything.

Do you have a link or can you explain how i take the pump out to check it and or clean it? I know i drop the straps by taking the bolts out, but do i cut the seal to the tank and lift the lid off and reseal once i am done. How does that work for me to find out what is wrong.

Thx, Cameron

 

I have been having a similar problem with my truck (I6 4.9 liter). The past few months the truck is hard to start and keep running but once it is warmed up it runs like a champ. As long as the truck does not cool down I can restart with no issues. The problem is starting the truck when it hasnt run for awhile. My gut tells me that it has something to do with the carb, and my knowledge of the carb is limited at best. Any advice would be appreciated.

 

Not trying to be rude but that might require a new thread. Sounds like a fuel pressure problem or battery issue though. Sorry, just mine is a fuel injection and yours is a carb, BIG differences. And if it is the carb, get a rebuild kit and follow the instructions. Make sure you clean it(soak it in carb cleaner) and than put it all back together. Sorry if i sound rude but it has nothing to do with the issue i asked for help with… Best of luck

 

Cameron,

The pump/sending unit are held in with a large ring. I think there is a gasket/o-ring under it. Look at this...

DIY : Replace a F150 Fuel Pump - Truck Forums

If you search for parts or images you should see what it looks like.

Jim

 

Caldwell F150,

What year? Is it an electric or mechanical pump? The mechanical ones also have a check valve I believe. Either way you should see if it is losing pressure over time.


Rockaholic,

You should also confirm the pressure in both of your cases. Is the rear system dropping over time as it sits? What happens to the pressure in the front system when it starts to loose power?

Jim

 

Read the article but To remove the bed i just remove the bolts underneath my liner right? than lift and presto i can access it no problem? can i do this by myself? or should i wait to have help? Never removed my bed before. Going to get new body bushings while i have it off, might as well.

For the fuel line problem you mentioned, so there is a fuel line inside the tank itself? that runs into the lower sump part? and your buddies happen to have a crack in it if i am not mistaken. Do i replace whole pump and or is there a way to CLEAN the pumps once i have the bed off??? Would love to get a few thousand more miles out of these things before i replace them. Thx for article though.

 

Front looses power at higher rpms, rear is a slug at low rpms and kicks in around 2.5k and pulls steady to well over 4k. It is a very odd combination. I have never heard or seen it before.

 

I do not remember what brand his system was on other then it was a motor home. All he had to do was replace the small piece of tubing. All I was suggesting was maybe there is some similar issue in your tank. I guess you could remove the box by yourself if you have a way to lift it off and over. You could lift it set it on something and drive out from under it. The bolts might be a tough job, you could just blue wrench them off.

Edit I guess if it kicks in at 2.5 and pulls to over 4 it could be a weak pump. I would try a pressure gage and take it for a ride, just make sure your plumbing is tight when you assemble the gage.

Jim

 

Jim - 1976 I6 in a 1982 F150 and the pump is mechanical. I replaced the pump with a new one about a month ago. Should I move/create another thread? David

 

Did oil change today and tranny fluid changed, Oil was horrible! never seen oil that brown besides in the 77 F250 i bought that sat for 2 years and the guy never changed oil, I might be looking at a tranny rebuild… looked like fluid was never changed!!! Was yellow and black! not a hint of red or anything just a nasty black and yellow… NOT GOOD! Either way it shifts smoother and i took the front air hose off the valve cover out and put a little filter there from parts store and did a small tune up. It actually helped a little with the issues. I will start on fuel pumps next. Just ordered my clifford headers from a guy online also. NEVER USED so when i do that i will devote a day to those pesky fuel pumps and lines. Thx for the help!

 

raising the bed is a one person job if you are strong enough to lift the weight, i did it this weekend in about 30 minutes, i unhooked the light wiring at rear of bed, disconnect fuel fill point screws and hose clamps, unbolted the 6 bed bolts, grabbed it on the drivers side wheel well, raised her up and placed 2 boards underneath to hold her up, make sure the other side is resting on the tire firmly, board should be about 3-4 foot long, add c-clamps for safety, i swapped out my fuel assembly in 10 minutes, had her back together 30 minutes later, how it runs now is another issue, and anotehr thread. PEACE