still wont start
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Junior User
Joined: Mar 2004
Posts: 94
Likes: 0
From: florida
still wont start
Ok ill try one more time in hopes that somebody can help me..i have a 1991 f-150 ext cab with the inline 6 and duel tanks..when i turn on the key i can hear the fuel pump in the front tank kick on and stay on..i have dropped the tank and gone as far as pulling off the inline fuel filter thatsby the frame and it is pumping plent of gas to there but when i try to start the tru ck it acts like there is no gas in the engine..any ideas what to check next?why is the pump still running? i know the truck has spark but wont start thanx for any ideas and help....
Laughing Gas
Joined: Jul 1999
Posts: 1,047
Likes: 22
From: Lacey, WA
Hi,
Does the engine spit and sputter at all when cranking? In other words does it fire at all?
If you pour some gas into the intake and crank it will it run at all?
Takes 3 basic things for a gas engine to operate: Gas, spark and timing. You say you have spark and if you pour gas into the intake and it briefly runs you have good timing. OK lets look at gas, or lack there of.
Now I am no expert on FI engines but since no one else has chimed in I will try. I believe that on your fuel rail somewhere there may be a schrader valve. Looks like a big valve stem. You can check your fuel pressure there. You will need to buy a gauge for this. I am guessing that you would see 35-50lbs here with the pump running. You may need to buy a Haynes or Chilton to confirm. If you where to have low fuel pressure I would consider the fuel pump or fuel pressure regulator valve. The valve is located at the output of the fuel rail. It may have a vacuum line going to it. It is suppose to regulate the fuel pressure based on manifold vacuum. The output of this valve sends fuel back to your tank. If this valve where stuck open then it would be hard to build pressure in the rail for the injectors.
Also, I know that some vehicles have more than one electric fuel pump. Some have a low pressure pump and also a boost pump. I would check this out also as one of yours could be ka-put! Make sure a fuel pump fuse is not blown.
Hope this helps,
Lee
Does the engine spit and sputter at all when cranking? In other words does it fire at all?
If you pour some gas into the intake and crank it will it run at all?
Takes 3 basic things for a gas engine to operate: Gas, spark and timing. You say you have spark and if you pour gas into the intake and it briefly runs you have good timing. OK lets look at gas, or lack there of.
Now I am no expert on FI engines but since no one else has chimed in I will try. I believe that on your fuel rail somewhere there may be a schrader valve. Looks like a big valve stem. You can check your fuel pressure there. You will need to buy a gauge for this. I am guessing that you would see 35-50lbs here with the pump running. You may need to buy a Haynes or Chilton to confirm. If you where to have low fuel pressure I would consider the fuel pump or fuel pressure regulator valve. The valve is located at the output of the fuel rail. It may have a vacuum line going to it. It is suppose to regulate the fuel pressure based on manifold vacuum. The output of this valve sends fuel back to your tank. If this valve where stuck open then it would be hard to build pressure in the rail for the injectors.
Also, I know that some vehicles have more than one electric fuel pump. Some have a low pressure pump and also a boost pump. I would check this out also as one of yours could be ka-put! Make sure a fuel pump fuse is not blown.
Hope this helps,
Lee
