Further thoughts on diagnosing motorhome’s drivability problem
I want to take a second swipe at David’s intermittent motorhome drivability problem (discussed last week).
As a former GM dealer shop foreman, I would often drive a customer’s vehicle home and back as if it were my own for perhaps a week or more until I was lucky enough to encounter the situation with the appropriate diagnostic tool in hand. David’s problem is so erratic/intermittent that multiple dealers have failed to encounter the fault or take action to look very far in to it.
Oneof the pitfalls of automotive lemon laws is itmakes the dealer reluctant to attempt a repair unless there’s a documentable reason to proceed, and a potentially favorable outcome, as it counts as strike one, two or three in a potential buy-back case. Itmakes complete sense as a business decision to say “NTF” (no trouble found) instead of trying something helpful. I wonder if the doghouse (engine cover) was ever lifted.
David’s frustration and fears of a safety concern due to power loss has him contemplating a lemon-law buyback case. Oregon’s automotive lemon law is less favorable to consumers than some in other states, and even if he prevailed, he’d be facing a significant ($20K) financial loss (vehicle is bought back at depreciated value).
I had recommended a Ford VCM-2 customer flight recorder be temporarily loaned and attached, but the dealer and Ford corporate both declined to step up. Yesterday my students Brian and Jesus drilled deep into the $70 Autel ML529 scan tool I just purchased for personal use, and to share in class, and found it has a data recording feature! I never would have imagined such an inexpensive tool would do this. The ML529 is an upgrade for the previously recommended ML519 tool. Perhaps David might take matters into his own hands, purchasing such a tool and taking a movie of the 25 or so available OBD-II generic parameters the next time the symptoms surface (scanner is previously connected and awaiting a “record” command).
Two caveats: The OBD-II data list is not nearly as extensive as the manufacturer’s tool, and the recording is only of the time after being triggered, as opposed to before/during/after on a manufacturer’s tool. About half the fuel cost for another dealer repair attempt, and itmay get David on base with justification for additional diagnostic procedures due to a captured irregular parameter!
Another recommendation, especially considering the inconvenience, fuel costs for repair attempts and potential financial loss of a buy-back, is to throw perhaps $500 at this in diagnostic time for a really sharp dealer or independent diagnostic tech to physically burrow in, checking PCM (powertrain control module) power and grounds, and critical sensor inputs, using a graphing multimeter or lab scope as the motorhome is driven and connectors are wiggled. Sometimes an intermittent fault leaves little clues even when it’s not acting up large. Physical inspection of connector seating and pin-fits and wiring harness routings are also prudent, as this problem showed up before the wheels even left the parking lot when purchased as a new vehicle.
The fault may lie somewhere between the coach builder and the Ford chassis/ powertrain as a build boo-boo. Reimbursement may be a long-shot but a solid fix is a game-changer for enjoying the motorhome as it should be. Look for a tech with ASE Advanced Engine Performance L-1 certification, these are the best at what they do!