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Saturday, December 5, 2020

Doug's Domain

Doug Vetter, ATP/CFI

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Sunday, March 29, 2015

Winter Summary and Winter Sport 4D Review

New Jersey experienced what I'd define as a colder and snowier winter than normal. Average high temperatures are supposed to be in the low 40's but for the better part of the season temperatures struggled to get out of the 20's. We also had a series of storms that dropped an average snowfall of 6-10 inches. That managed to keep all the grassy surfaces covered in snow and the roads covered in salt for the better part of the last three months.

I made a concerted effort to avoid driving in predicted snow events but NOAA really seemed to be off their game this winter. They botched the forecast of nearly every storm in both directions: first, they predicted a "historic" storm that never happened for us and then they predicted several tiny storms that ultimately resulted in 6+ inches each time. I wound up on the road twice when I probably shouldn't have been driving -- once due to this botched forecast and another time due to a family obligation. On the upside, I'm sold on the use of the car cover during storm events and plan to continue to use one until I leave New Jersey behind and get a garage attached to a house that won't cost me my retirement savings.

My overall impression of the Dunlop Winter Sport 4D remains quite positive though I could tell they were more confident in their first season, particularly in the rear where my overzealous use of throttle on the daily commute tended to erode the tread at a slightly faster pace. Although I could probably squeak a third season out of them I'm likely to buy another set this fall since the tires are reasonably priced and I find it self-defeating to drive a car with winter tires that are in any way compromised.

PSS Return to Service

(Image: E36 after installation of summer rubber)Last August I swapped the PSS for the WS4D just before sending the car off for paint. The car remained in the shop longer than anticipated so I just decided to keep the WS4D's on the car for the winter. I've learned over the years that the chance for snow diminishes quite rapidly around these parts as March comes to a close. This year was no exception: with temperatures forecast in the 50s consistently for the next 10 days I figured the worst of winter was over and I could transition back to summer rubber today.

Although I didn't have any problems removing the wheels I did notice that a couple were more stubborn than usual. Still, this was nothing compared to my experience with the E46 last fall, so I made quick work of the swap, pumped all the tires up to spec, gave her a bath and then set off for home. The first turn reminded me why I love the Pilot Super Sport on this car.

In fact, I love the PSS so much I've bought a set for the E46 to finally rid myself of the crappy Bridgestone runflats that have plagued that car since birth. And I'm finally moving to a full size spare as well but you can read about that later. I scheduled the installation with my dealer to coincide with an airbag recall and some firmware updates to address a lumpy idle. Can't wait to feel the PSS go to work on that car.

Engine Vibration Revisited

While it's clear to me that the engine is vibrating more than normal throughout its rev range I've concluded that the persistent vibration at idle may in fact be caused by a lower than normal idle. I didn't notice it at first, but the vibration is worst when the engine turns over around 500RPM. Normal idle is around 650.

The problem is I don't know what's causing the low idle. The DME manages the idle RPM automatically via the Idle Control Valve (ICV) so there's nothing to adjust. My guess at the moment is I have either a dirty / defective ICV, a very small vacuum leak somewhere, or the mixture is too rich due to worn pre-cat O2 sensors which are now almost 15K miles beyond their recommended replacement interval. As I noted in my O2 sensor replacement article worn sensors trick the DME into thinking the engine is running lean so the DME naturally richens the mixture. This will in most cases load up the engine, particularly when sitting at lights in gear, and this is the behavior I'm seeing.

I replaced the ICV many years ago as part of my preventative maintenance schedule and fortunately kept the old, fully functional part. So I'm now planning to install that in an effort eliminate the ICV as the cause. If that doesn't do anything I'll replace the pre-cat O2 sensors. As a last resort I'll search for a vacuum leak, which really means smoking the intake, but I hope it won't come to that because I don't know anyone with a smoke machine. I could buy one but they're not cheap and I hate buying tools I expect to use exactly once.

While I still expect to overhaul the engine I want to do everything possible to try to push that task into next year, as the interior work is a huge job in itself and frankly the time I have to spend working on my cars is diminishing rapidly.