Saturday, June 4, 2011
PO171 & PO174 Code Cause In Ford 6.8L Triton Engines
Because of e-mail inquires about a very common problem with PO171 & PO174 Lean Right Bank codes on the 6.8L Ford V10 Triton engine, I made this movie to illustrate the most likely suspect. A customer’s 1999 Ford F250 Super Duty truck with 6.8L Triton engine came in with the check engine light on, and the engine loping (revving up and down in RPM). The PCV hose running from under the front center lower throttle body to the right valve cover PCV valve (Crankcase Ventilation Valve) deteriorates where a sharp bend in the hose routes the hose to the valve cover. Once this bend in the hose rots and causes a vacuum leak many performance problems crop up – loping engine, lean miss, stalling, high idle speeds, hesitation, power loss, and the PO171 & PO174 code combo. The fix I do for this is to change out the sharp bend with a plastic connector. It’s a little time consuming but the hose never causes the same problem again.
The second part of the movie pertains to taking off the individual coil assemblies, spraying into the spark plug hole, and allowing a soak period before removing the spark plugs. These 6.8L & 5.4L Ford engines are infamous for stripped threads and actually blowing spark plugs out of their holes. Replacing them even with careful precautions can end in having to install thread inserts when the threads get damaged during removal. The Timesert 5553 repair kit is the best tool set for repairing these potential disasters.