Where does it hurt, Ruby?

Today I pulled out to pass a minivan and the car began to shake.  I’d been expecting this.  At 127,000 km Ruby’s overdue for Cardan shaft work, so I eased out of traffic and skulked home, avoiding accelerating on hills to lessen the strain on the drivetrain.

Up onto the hoist Ruby went.  Off came the covering plate, and there was the carrier bearing, its rubber membrane cracked, but still in place.

Nonetheless, I set out with a knife to hack the thin rubber membrane away, then followed with an air-driven hone to polish the last of the rubber off the carrier bearing.

Unwilling to leave the bare metal to rust, I sprayed several coats of black shop paint in the general direction of the bearing case.

Then came the Jimi Fix.  As claimed, it was a “twenty-minute” procedure to compress a series of cross sections of heater hose between the bearing and its frame and hold them in position with a latticework of zip ties.  By the second hour of the twenty minutes Bet had warmed to the job and insisted that I lower Ruby  on the hoist “another inch” so that she could finish the last three ties at the top of the bearing.  (My left arm was out of commission at the time due to a couple of pinched nerves from several days under the steering wheel, fighting with A/C boxes in an impossible location.)

We cut off the ends and back on went the plate which hides everything, and Ruby seemed as good as new.

But when I started up, the “Check Engine” symbol popped.  Ruby idled roughly as I backed out of the garage, then showed an ominous triangular warning, so back into her nest she went.

The meter showed Error Code P0307.   Google told me that means a misfire on cylinder 7.  Off came a panel covering the left hand coils, fuel injectors, and spark plugs.  The various specialized screws and nuts weren’t about to stop me after the A/C actuator experience last week.  Out came coil #7.  Yep, a 2″ split right there on the side of the coil.

I ordered a set of eight from Amazon.ca, called it a night, and watched the Jays beat the Orioles with a three-run, walk-off home run in the bottom of the eleventh.

The rubber on the bearing support was brittle and cracked, though strictly speaking the Jimi Fix had been premature.  Even though Ruby’s Cardan shaft had felt much sloppier than the new one on my son’s 04 Cayenne S, the bearing carrier had still been functional when I butchered it.

Update:  10 October, 2016

The coils arrived from Vancouver Island in four days.  As soon as I slipped a new one into place, Ruby’s engine settled right down.  Why the disproportionate reaction to a single mis-firing cylinder?  Charlie explained that the unburned fuel alerts the O2 sensor, which then leans the whole bank of cylinders out to try to rectify the problem, so a single misfire affects four cylinders.  That made sense.

BTW:  Until that plastic cover removed to access the coils is properly screwed down, the engine seems alarmingly noisy.  It’s likely fuel injector noise, but to my fevered imagination it just had to be the dreaded start-up death rattle of Cayenne V8’s. Once the cover was properly installed, Ruby purred once again.

Ruby has returned to normal duty.  The drive shaft works fine, so I’d have to conclude that the Jimi fix seems a viable solution to a Cardan shaft problem, at least in the short term.  Ruby now has 127,500 km on the odometer.  I’ll report back on this periodically.

Update:  25 December, 2016

At 131,000 km Ruby’s Cardan shaft still performs perfectly.  We tested it over the last couple of weeks with a 20′ enclosed car trailer in tow, and offroad in low range with the diff lock on.  Not a whimper.

16 December, 2017: Still no problem with the drive shaft at some mileage north of 146,000 km.

31 December, 2016  

On Rennlist.com the original contributor just posted the following update:  Traded Cayenne S with Jimi fix away. Logged mileage with Jimi fix perfectly working was 44,632 miles. Yeah…