This is a fun one, when using the rear tank on my 1994 F250 with the 351, the motor will die when come to a stop. Never happens on the front tank, and only does this every once and a while on the rear tank. Does any one have an idea what my problem could be?

 

Nobody has any ideas?

 

loose connection?

 

I checked all the electrical connections for the ignition and fuel supply and everything seems fine, this problem just has me stumped.

 

I have one. I'm gonna guess that the tanks have separate fuel pumps. My idea is that the rear tank pump is failing or the connector is loose.

If it never happens with the front then the only things it can be are those things that are specific to the rear tank.

 

I have checked out everything I can without dropping the tank and pulling out the fuel pump. The weird part is that aside from dying when coming to a stop, the fuel pump does not show any of the signs of imminent failure.

 

check fuel pressure at the rail when on the front tank then do the same for the rear tank. if the pump is failing you will see it on the gauge.

also i dont think you have a C6 behind that 351 unless it was swapped in.

 

Good idea, I will check the fuel pressure.

And yes, the truck has a C6 that came stock in the truck when my grandfather bought it new off the lot in 1994. I believe 1994 was the last year the C6 went into these trucks.

 

wow, learned something new. thanks

let us know what the fuel pressure is. also is there a sepereat fuel filter for each tank or is there on 1 common filter thats shared between the 2 tanks.

 

I'm going to go out on a limb here and guess that it's not the fuel pump. If it is getting enough gas to run at crusing speed it should be able to provide enough at idle. My second investigation - after the fuel pump- would be to see if the tank vent and hoses are in working order. Does the tank make a vacuum (sucking) sound when you remove the gas cap? This is what I would check after eliminating the fuel pump.

Doug

 

An excellent idea!! Try running the truck without a cap on it on the rear tank. It may cause a check engine light-but if the trouble goes away with the gas cap off-it is a tank venting issue.

 

I have to go get a fuel pressure gauge today so I can check pressure, but I will check out the venting today. I agree that the fuel pump might not be the issue, because it cruises, accelerates moderately, and runs WOT with no problems whatsoever. I have experienced bad fuel pumps and this would be the first time that I have seen one start failing on deceleration.

The venting also makes sense because there has always been problems with that rear tank sense the truck was brand new. It is almost impossible to fill past 3/4 and the only time you a vacuum sound when you remove the cap is when it is hotter than hell.

Thanks for the help everyone, hopefully I will know what the problem is today.