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Monday, June 24, 2024

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, February 17, 2007

Oxygen Sensor Update

After two tanks of gas, the DME adaptation program appears to have recalibrated itself to the new oxygen sensors and the results are in: when I take the number of miles on the trip odometer and divide that by the number of gallons taken onboard from the same pump at the same gas station until the pump clicks off, I come up with some promising numbers. Fuel efficiency has increased exactly 2MPG.

(Image: Comparison of power steering hoses)It's not much, but it proves without a doubt that oxygen sensors do change as they age. The engine feels a bit peppier as well and it's not my imagination. Given that power output decreases with an overly rich mixture and the fact that the mixture is now closer to the stoichiometric ideal it's likely that the engine is indeed producing more power. Overall, I'd say that replacement of the O2 sensors was money well spent.

I spoke to my dealer about the labor cost to replace the cats if necessary and it turns out book labor is only 1.5 hours, or about $170 with tax and that includes the labor necessary to swap the O2 sensors from the old to the new midsection. For that price, this is one of those jobs better left to the pro with the lift and a transmission jack or two, and so it shall be....assuming I see the cat efficiency warning again. If I don't, the cat replacement project will remain on hold indefinitely.

Power Steering Overhaul

I called Tischer the Monday after I realized I had the wrong high pressure hose and Jason handled the return perfectly. I put the hose and some 24.0mm swaybar bushings I never used into the box and sent it back to him via USPS mail for $5. He got the package in two days and promptly credited my card for the full amount of the purchase. I couldn't have asked for better service. Way to go Jason.

To avoid getting the wrong hose again I decided to source the replacement high pressure hose from my local dealer. The parts guy was able to take the partial part number I obtained earlier from the hose and order what he believed to be the correct part. When it came in, it looked a lot like the hose on my car, but I couldn't be sure since I hadn't removed the hose for a direct comparison.

When I got the invoice I freaked. This hose retailed for $225, a full $100 more than the hose depicted in the ETK for this application. This was far more than I wanted to spend on this project, particularly because the high pressure hose wasn't in bad shape (or so it appeared...you really can't tell their condition from the outside), but I figured "in for a penny, in for a pound" and swiped the credit card. I was just happy to have the correct part....or so I thought.

I finally got around to doing the hose swap today. It took me 2 hours and 45 minutes to do the swap, take a short test drive, and bring the oil level in the reservoir up to the proper level. This turned out to be a three curse job. I cursed once when I realized that the hose my dealer provided was the wrong one....again. I cursed two more times dealing with the reservoir (read about it in the coming DIY). The leaks related to the rubber hose ends at both the reservoir and the pump appear to be fixed, so I consider this mission accomplished, in spite of the part snafu.. I plan to return the incorrect hose for credit and give them one more chance to source it correctly before I let my fingers do the walking.

(Image: Closeup of CDT 6x9 free air subwoofer)Book labor for this job is 3 hours or $330 (2.0 hours for the hoses and 1.0 for the fluid flush). And yes, that's ridiculous, but that's the problem with book labor. Not only is it usually double the actual time a good tech would take to do the job but they'll never combine labor on related jobs to save you money. The fact that a fluid flush is part of the hose swap and doesn't actually require any additional time is immaterial to them....which explains one of the many reasons I now try to do things myself whenever possible

Mileage: 139200, Parts $205, Parts cost saved: $75, Labor Saved: $330

More Stereo Upgrades

I've had plans to replace the rear speakers for some time but couldn't figure out what I wanted to use. I considered installing 8" subwoofers in place of the factory HK 6x9 units but the one installation option that appealed to me (JL Stealhboxes) were apparently discontinued for the E36 this month -- talk about timing. That's probably just as well, though, since they were very expensive and came equipped with a subwoofer I knew I wouldn't use. It was not possible to order the enclosures separately. That brought me back to 6x9s and the only real choice available at this point -- CDT 6x9 free-air subwoofers.

When I looked on CDT's site I found a dealer a couple of miles away from my mother's shore house. As luck would have it I had already planned to be down there last weekend to install a PC and internet access for the business, so I dropped by SoundsGreat to pick up a pair of the woofers and their 1" soft dome tweeters. I read on bimmerforums that the CDT 6x9 drivers will not fit the OE 6x9 adapters but the models offered by Bavarian SoundWerks would work, so I used a discount coupon I'd received over the holidays and ordered them with a slight discount.

If you're wondering why I couldn't just throw a set of coaxials in there it has to do with the fact that the HK amplifier contains the crossovers and does not send a full-range signal to the existing 6x9 drivers. You need components for this installation. And before anyone starts to compose an email to me about how the rear speakers should be low-end / fill only and putting tweeters in the back destroys the soundstage, stop right there. I know all about it, and I'm not necessarily planning to keep the tweeters installed if I replace the amplifier...I just don't know when I'll get around to that and the OE system has tweeters back there.

Total cost of the speakers and adapters was $250, but I'm not officially "booking" this expense until I replace the drivers. I have some other mechanical work to do before I tackle the speakers, so it may be a few months before that happens, but you'll read about it here when it does.