Hey everyone, I am new here as you can tell. I tried to do a search for my exact problem and really didn't come up with anything or a solution so i am hoping some of you guys here can put me in the right place. So with that said here it goes. My car has a double pumper and it is tuned on 93. I also have 2150 cc injectors with AEM fuel rail. When the car is at a full tank, she performs flawless but when i get to a 1/2 tank or little under when i do a pull she starts to break up and goes about 1. lean(around 12.3). But like i said if she is at a full tank she stays right at 11.3. Any help on where to start looking i would appreciate it. For some reason i am thinking maybe one of the hoses has a small hole in it thats bleeding out but would like your guys/gals opinion since there is much more experiance with this type of car in here then I have.

Thanks and appreciate any feedback.

 

Also forgot to add spark plugs are new

 

Fuel pump may be on its way out

 

You on a full blown double pumper? Sounds like you are running one side of the tank nearly dry. The full blown unit replaces the factory siphon tube and some people have had issues with it not drawing from the passenger side of the tank.

 

Fuel pump may be on its way out

 

Ok I'll pull the pump out and check the siphon tube part that's in the tank to make sure it is good. The fuel pump kit is a buscher. I didn't install it the previous owner did but he said he never noticed the problem Appreciate the help

I would think if one of the fuel pump was going bad it would do it all the time not only when at a half a tank.

 

I pulled the fuel pump out when at half a tank and the tank was pretty much full, so that tells me the siphon system is working. Also made sure the siphon tube was correctly installed per buschur, which it was. Anyone else have an idea to what could be causing this? Do these fuel pumps fail like that, at a full tank it would work fine untill you hit a half a tank? Any help wpuld be appreciated.

 

What side was full? If the pump side was full and the passenger side was empty, this is a problem. Or vise versa. This means that the siphon tube is only pulling from one side and not the other. The system should pull from both sides so that they equally drain. Its not going to drain one side and then the other.

That would make sense why it is leaning out. Its getting air in the system only pulling fuel from one side.

 

The pump side (driver side) seemed almost full. I did not open the passenger side tank