Recall In Review: 07S49

March 23, 2007   As bizarre as this may look, flames from a tail-pipe are not unheard of by any means. Ask anyone that has improperly set the floats in a carburetor or watched a stock car race at night. But this is a diesel and these kinds of things don't happen right? What you are looking at is a 2008 model truck equipped with a diesel engine that has an exhaust after treatment system and the result of an obvious malfunction. All diesel engines built and certified for highway and off road use after January 1, 2007 are required to have an exhaust after treatment system to meet the requirements of tightening Federal emissions standards. Apparently we are learning new things about these systems as we put them to the test on the streets. The related video clip shows one such lesson in action, however the DTS does not know the origin of the video therefore we do not know where, or when it was shot and what the root cause of this thermal event was.

The after treatment system uses a Diesel Particulate Filer, or DPF, which is designed to collect and incinerate diesel particulate matter that is produced by the combustion process in diesel engines. This process is known as “regeneration” and it is automatically performed under certain operating conditions to clean the DPF and reduce system back pressure caused by the collected diesel particulates. To burn the particulate matter, the exhaust temperature needs to be elevated to around 1100ºF. The 6.4L Power Stroke® engine achieves and regulates this heat by injecting small amounts of fuel during the exhaust stroke as it monitors the exhaust temperatures though the use of three temperature sensors located in the exhaust system. On a couple of rare occasions, a fuel injector or the turbo has failed, combined with the normal regeneration process and produced a flame. These types of failures allow unmetered fuel or uncontained engine oil to mix with the exhaust gasses and ignite if the exhaust temperature raises high enough.

Details on the safety recall 07S49 are limited but the recall states that the PCM recalibration is “to limit these temperatures in the event of this rare combination of events...” What you have to understand is that manufacturers do not reveal things like calibration information and just how the new calibration will limit the exhaust temperatures or what was changed. We can speculate that a limit was never set, the tolerances were not tight enough or a limit was not thought to be necessary. After all, oil and fuel is not supposed to be getting into the exhaust and perhaps this kind of “thermal event” did not occur during the extensive testing period. We may never know but we are pleased to see that this concern has been identified and addressed early on. You never can tell what will unexpectedly turn up as new technologies progress.

Recall 07S49 was released on March 23, 2007 which requires the affected vehicles to have their Powertrain Control Modules recalibrated. If you own a 2008 F-250/350/450/550 vehicle equipped with a 6.4L diesel engine that was built at the Kentucky Truck Plant before March 9, 2007 you will receive a recall notice to have this recall performed. You may contact your local Ford dealer to see if your vehicle is affected or you can also visit http://corporate.ford.com/news-center/news/recall-information to research Ford recall information.