I need help solving my fuel system problem...im running an walbro 255 fuel pump and a 99 corvette fuel filter with a sumped tank. The problem is after about 20 mins of driving the car its as if the motor is starving from fuel. Yesteday after i sumped the tank and drove it around it was fine until i got on the freeway,at higher rpms its like the car is not getting enough fuel. Has anyone experienced this problem?

 

im guessing that you are running a inline pump.

it could possibly be overheating. where is the pump located? good enough airflow? check your grounds, poor grounds and poor airflow combine to make lots of heat and are bad on a pump.

maybe someone else has better idea.

 

When that happens try unscrewing the gas cap. I bet you hear a huge rush of air into the tank and then it runs good for a while. Sounds like the tank isn`t being vented.

 

doh..........never thought about that

 

I am running an inline pump that is located in front of the tank. I double checked and made sure everything was properly grounded. Im guessing maybe the pump should be ran under the drivers side door?

 

I'm running the same pump and filter both about 4 inches from the tank. It is just a stock tank with factory sending unit and 1/4 dia return. No issues have been noted with this setup. Not even fuel starvation on a low tank. Guess I'm just lucky, or it's just prove you don't really need a sumped tank to run the ls1 in a highway cruiser. Of course my factory A body tank is at a pretty good angle sloping down in the forward end which keeps all the fuel in the front bottom of the tank were the sending unit and pickup are located. Fuel would have to slosh up a pretty good hill to go aft from the pickup.

 

I like to install my pumps with a sump for a few reasons, first off alot of older cars had very small fuel lines for the feed and this can cause a restriction to flow. Also during hard acceleration and cornering you can cause a fuel starvation condition due to the tank not having a sufficient baffling system to keep fuel at the inlet for the feed.

Where is your pump mounted? Do you have a pre filter on the unit and are you sure it is installed in the correct flow direction? The pump needs to be mounted close to the tank as it is a better pusher than puller, you also need to make sure to run a stout power and ground system to insure proper current flow and less voltage drop. I have 40 plus of these units running around on converted cars with no problems...... Not saying they don't fail but usually it's a cause and effect situation ya just gotta find the cause....

 

Im gonna try two things...first im gonna run a prefilter and also im gonna double check the correct flow direction,hopefully this will solve my problem. I know alot of people with this same setup but they are not having this problem so im guessing more than likely its a flow direction problem.

 

Is the setup not currently running a filter? I am sure you have the pump in correct but a backwards filter can cause problems. Also if you do not currently have a filter before the pump I would remove the pump and check the inlet for any restriction.

 

Im currently running a 99 corvette fuel filter but my guess is that the fuel filter can be on backwards. Im gonna check and make sure that its not on backwards and that the inlet is not restricted.

 

check the inlet of the pump.

you really need to have a prefilter at the beginnig of the system. that way our pump never has to pump dirty fuel.

the corvette fuel filter wont work hooked up backwards if im not mistaken... i would look at the gas cap. becase it sounds like your pullin a lil vacuum.

just take the cap loose and go cruize. if it still does it, then its gotta be flow related.

 

Thanx im gonna take all of this into consideration and see what results i come up with.