shiftless
Active Member
Hi fellas, I am trying to diagnose a problem with the 351W Mustang. Basically, sometimes at WOT it will sputter like its not getting fuel.
The problem is intermittent, sometimes it will pull like hell with no problems, other times it will act up. It seems to be more likely occur during a high G-force acceleration. For example, if I take off from a red light quick and nail it in 1st or 2nd gear, it may sputter at the top of 2nd or 3rd. Most times when I drop it down to 3rd and nail it from a cruise, it will pull fine through 3rd-4th-5th, but not always. It also seems to be more likely to occur during the middle of the day when the engine and outside temp is hot.
I know it's not the pickup being uncovered in the tank because the problem will still occur with a full tank, plus it often starts sputtering before air would have a chance to be sucked up from the tank all the way to the carb.
I noticed at idle the fuel filter would often contain very little fuel or be empty, and as the engine idled you could see that the filter was draining out faster than it was filling up. I figured the fuel pump was probably going bad so I replaced it tonight. Now the filter stays full but it didn't cure the stumble. It does seem less likely to occur now though.
Another thing I noticed is if I decelerate very quickly--like getting on the brakes hard for a red light or especially when braking hard going downhill--the engine will idle down real low or even stall out in worst case, but will recover itself after sitting there a couple seconds. It also sometimes acts up a bit when making sharp turns.
The carburetor is an Edelbrock 600 (Carter AFB design), new, unmodified.
What do you guys think? I am no expert but I am thinking these problems might occur if the carb float level was set too low.
The problem is intermittent, sometimes it will pull like hell with no problems, other times it will act up. It seems to be more likely occur during a high G-force acceleration. For example, if I take off from a red light quick and nail it in 1st or 2nd gear, it may sputter at the top of 2nd or 3rd. Most times when I drop it down to 3rd and nail it from a cruise, it will pull fine through 3rd-4th-5th, but not always. It also seems to be more likely to occur during the middle of the day when the engine and outside temp is hot.
I know it's not the pickup being uncovered in the tank because the problem will still occur with a full tank, plus it often starts sputtering before air would have a chance to be sucked up from the tank all the way to the carb.
I noticed at idle the fuel filter would often contain very little fuel or be empty, and as the engine idled you could see that the filter was draining out faster than it was filling up. I figured the fuel pump was probably going bad so I replaced it tonight. Now the filter stays full but it didn't cure the stumble. It does seem less likely to occur now though.
Another thing I noticed is if I decelerate very quickly--like getting on the brakes hard for a red light or especially when braking hard going downhill--the engine will idle down real low or even stall out in worst case, but will recover itself after sitting there a couple seconds. It also sometimes acts up a bit when making sharp turns.
The carburetor is an Edelbrock 600 (Carter AFB design), new, unmodified.
What do you guys think? I am no expert but I am thinking these problems might occur if the carb float level was set too low.
