Engine hesitates and sputters
Problem: the engine runs fine when cold. Once it is warmed up, it hesitates and sputters when accelerating. I don't know if it's related to the problem, but the fuel pump is pretty loud at first. About the time the hesitating and sputtering starts to happen (when the engine warms up) the fuel pump sound changes and gets much quieter.
Specs: new (re-manufactured) Small Block Ford (302) with stock heads, stock roller cam, Weiand 8124 dual plane intake manifold, stock cast exhaust manifolds (02 sensor is on the passenger side), new full exhaust system (Y-pipe to a single tail pipe and muffler), new Pertronix stock-look distributor with Igniter III module and Flame Thrower III coil, FiTech Go Street 400 HP system with frame mount in-line fuel pump (Kit #31003). FiTech is NOT being used for timing control or radiator fan control.
Here are two data log files:
https://www.dropbox.com/sh/p0ngwb7ino83tdr/AAA9jD8QY2bXqpuDMQPbIdfMa?dl=0
Basic Sensors1 is from a short drive around the block and there were several instances of the engine hesitating on acceleration.
Basic Sensors2 is just idling.
Any help and suggestions are greatly appreciated!
David
First of all. Thanks for all the information. It is obvious you have studied.
I am going to start with fuel pressure. Do you have a FP gauge? When you start driving, the engine goes lean. Everythinh else looks good. You may have a fuel supply problem. May show good pressure at idle, but cannot supply demand...
Thanks, Austin. I'm working on getting a fuel pressure gauge so I can check pressure when driving.
David
The problem seems to be solved. I had installed an extra fuel filter, upstream of the FiTech pre-filter, and that filter was partially clogged and definitely not capable of providing enough fuel flow. I took the filter out and now the car runs great!
Thanks for the help!
David