Case Study: F-550 stalls intermittently, extended crank on start-up

Jan. 11, 2023
This vehicle was brought to the shop because the malfunction indicator light (MIL) was on, and the engine kept stalling intermittently. Also, the engine occasionally took a long time to start.

Vehicle: 2017 Ford F550, 4WD, Super Duty, V8-6.7L DSL Turbo

Mileage: 140,598

Problem: This vehicle was brought to the shop because the malfunction indicator light (MIL) was on, and the engine kept stalling intermittently. Also, the engine occasionally took a long time to start.

Case Details: The technician also noticed the problem got worse when the engine was warm. He connected a scan tool and found the following diagnostic trouble codes (DTCs):

P027A - Fuel Pump Module B Circuit Open

P064A - Fuel Pump Control Module A

U0109 - Lost Communication with Fuel Pump Control Module

The truck had been at the dealership. They replaced the low-pressure pump and re-flashed the engine control module (ECM) but that did not fix the problem. The technician took a known good fuel pump control module (FPCM) from another truck and swapped it out. Still no luck. At this point, the technician called ALLDATA Tech-Assist.

The Tech-Assist consultant suggested checking the FPCM connector and fuel pump connector because their location leaves them exposed to the elements and large temperature changes, which has a big effect on electrical circuits, connections and modules. The consultant also advised looking at connector C1415 near the master cylinder. Poor electrical connections at that connector are a common problem.

The technician started wiggling connectors when the engine was running. The engine stalled when wiggling the connector C1415. The tech found a poor pin fit and some corrosion in the connector.

Confirmed Repair: First, he cleared all the DTCs and then repaired the connector pins. Afterwards, the engine started up normally. He tried the wiggle test again with the engine running in the shop. The engine stayed running so he took it out for a test drive. No problems occurred. Problem solved!

Reprinted with permission from ALLDATA.

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