DEARBORN - A millimeter. It’s the thickness of the credit card that’s in your pocket right now. It’s the thickness of ten sheets of paper stacked up.
In other words, it’s a very small unit of measure and probably not something you could pick out with your naked eye.
But it was approximately one millimeter that was causing big headaches for Ford F-150 production at Kansas City Assembly Plant (KCAP). It took a 47-year Ford employee who goes by the nickname of “Cooter” to figure it out.
According to Brian Miller, resident Powertrain engineer for Kanas City Assembly Plant F-150 Plant Vehicle Team (PVT), the plant began having crankshaft sensor codes show up in end-of-line testing. It was an intermittent problem, but all were equipped with 3.5-liter EcoBoost six-cylinder engines.
Some were repaired by replacing the crankshaft sensor, but that didn’t work in several other vehicles.
That’s when Darrell “Cooter” Collins, Jr. came into the picture. When things can’t be fixed and aren’t in the workshop manual at KCAP, they send them to the quiet Midwesterner who speaks with a slight drawl.
Collins developed and carried out a fault tree analysis on the stricken engines. He looked at about six different angles to the fault tree – including a week spent on wiring, which he was able to eliminate as a cause and remove from the fault tree.
What was running through his head? “A migraine,” said Collins.
“He got mad at it. He spent his own time taking apart those engines. He was removing transmissions and digging into the crankshaft assembly on the back of the engines,” said Miller.
“I had to walk away a couple of times, but came back to it,” said Collins.
That’s what gets us back to the lowly millimeter.
When Collins looked at the engine of an unfixable unit, he tore it down piece-by-piece until he got to the pulse wheel. Miller says that wheel has 58 teeth, and each of those teeth make or break a connection with a magnetic sensor as the wheel spins inside the engine.
The system is supposed to identify when the No. 1 cylinder is at top dead center. In the case of the “unfixable” engines, the sensor identified multiple other cylinders as No. 1, causing the engine to sputter intermittently.
It was difficult, if not impossible to recognize with the naked eye, but Collins found one of the teeth on the pulse wheel was bent by about a millimeter.
“There was some skepticism on that. That kind of bend on that tooth shouldn’t have caused that,” said Miller. “Nobody could see it unless we put the arrow on it [with a marker]. Nobody would believe us.”
Miller sent Cooter’s information to the engine plant that ships that engine assembly, which found the root cause of the problem.
“That was a good day,” Collins said.
The engine plant communicated the failure mode to Ford dealers through Ford Customer Service Division, and suddenly, a formerly “unfixable” problem was now fixable. Dealers had a repair procedure to follow that was easier and took less labor. Vehicle downtime was dramatically reduced.
“It saves us multiple claims on the vehicle. The ones that truly had the problem could be fixed with one claim, one trip to the dealership,” said Miller.
Collin’s work made dealers and customers happy and personified Ford’s Go Further global brand promise.
“You have to ‘Go Further,’” said Collins. “With all the electronics we have, nothing’s easy any more. I don’t like to pull an engine unless it’s absolutely necessary. We had enough time and we figured it out.”
“A lot of people walk away from something within 10 minutes, and I don’t. And the engineers here [at KCAP] don’t,” Collins added.
So with a career spanning 47 years at Ford, and fond memories of working on Ford Mavericks, Ford Fairlanes, Ford Tempos and Ford Topaz’s, do you think Cooter is contemplating retirement?
“Well, I hope,” he said. “I’m going to try to make 50.”
“I may make a few more… if the aspirin holds out.”