Slowly going lean while driving
Posted: April 4th, 2022, 1:58 pm
First of all Iam new to the site although I have come here and got great info through my entire engine install. Just finished installing a ATK street stroker engine and added the ford 24lb injectors BBK 62mm throttle body, adjustable MAP sensor and the Hesco adjustable FPR and AEM afr guage.
The issue I am having is the afr reading is good during open loop operation 14.5-14.7 once the thermostat opens afr remains the same for approximately 10 min then it slowly starts going lean while driving to the point of 17.7 to 18. I raised the fuel pressure from 40 to 43.5 which just prolonged the time that it took to start going lean by a few minutes. Adjustable map is set to 5.3 volts. All sensors have been replaced during the install and I tested them as per the FSM procedures and all tested within spec. Does this sound like possibly a fuel pump failing under load or am i missing something else.
Thanks
The issue I am having is the afr reading is good during open loop operation 14.5-14.7 once the thermostat opens afr remains the same for approximately 10 min then it slowly starts going lean while driving to the point of 17.7 to 18. I raised the fuel pressure from 40 to 43.5 which just prolonged the time that it took to start going lean by a few minutes. Adjustable map is set to 5.3 volts. All sensors have been replaced during the install and I tested them as per the FSM procedures and all tested within spec. Does this sound like possibly a fuel pump failing under load or am i missing something else.
Thanks