Engine cut out whilst driving and vehicle was towed into workshop
P0261 - Cylinder 1 Injector Circuit Low
P0264 - Cylinder 2 Injector Circuit Low
P0267 - Cylinder 3 Injector Circuit Low
P0270 - Cylinder 4 Injector Circuit Low
P0273 - Cylinder 5 Injector Circuit Low
P0102 - Mass Air Flow MAF Circuit Low
Vehicle was found to be blowing engine bay fuse F9 when the engine was cranked.
Upon consulting wiring diagrams, it appeared that the only components on that circuit were the Fuel Injectors and Mass Air Flow sensor.
The Mass Air Flow sensor was disconnected and the fuse replaced. The engine started and the Mass Air Flow sensor reconnected - the engine continued to run. The engine wiring harness was wriggle tested however the engine did not cut out.
The vehicle was road tested and the live data from the Mass Air Flow sensor observed. During the test drive the live data from the Mass Airflow Sensor would flat-line at 5000rpm (4.7v) and engine power would drop off.
The Fuel Injectors were also scoped for excessive current draw, however all were within specification.
The Mass Air Flow Sensor was replaced and live data rechecked. The flat-lining issue was now resolved and power returned to normal/.
The vehicle was returned to the customer.
A few days later, the fuse blew again and returned to the workshop.
Obviously there was something more sinister going on, so the member purchased a short subscription to the Ford Technical Information Service and began researching further.
Upon doing so, an extra circuit was shown that was not evident on any of the wiring diagrams that had been provided so far.
There is a heater located in the Positive Crankcase Ventilation canister that so happens to be part of the oil filter housing and cannot be seen without removing the airbox.
Upon testing, it was discovered that the heater had a very low resistance and once unplugged, the fuse would no longer blow.
This did however cause the check engine light to illuminate.
In order to rectify the issue, the entire oil filter housing must be replaced as it is not a serviceable part.
Thanks to Brad McGrath from McGraths Automotive for sending in the report for this article.
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