Our ’02 Yukon Denali has been suffering from erratic idle at low speeds, especially with the air conditioner on, and occasional stalls at low speed, usually turning but not always. Querying Google for Yukon/Tahoe DIY information is generally useless but I did find these nuggets:

http://gmcowners.com/gmc-forum/showthread.php?t=15028
http://answers.yahoo.com/question/index?qid=20090820223923AA1m67n

They suggest replacing a bunch of stuff to start. The BMW had some stalling issues but its computers are great and always tell you exactly what’s going on. It suggested changing the camshaft position sensor and after doing so, the stalls disappeared. So I thought I’d follow the above articles and my own experience with the BMW and swap out about $700 worth of parts.

But the part about the throttle body intrigued me. I figure it’d take an hour and $2.00 worth of carburetor cleaner.

So, get your carburetor cleaner from WalMart for $2.00 or any gas station for $4.00 and some shop towels. Pop the hood.

First we have to remove the tubes/baffles going from the air filter to the throttle body shown here:

Yukon/Tahoe Intake Pipe/Baffles

It’s a really funny shape with a big empty baffle below and that long empty baffle on top to the right. Remarkably, this large assembly is only held on at three places.

Loosen the hose clamp near the throttle body:

Yukon/Tahoe Throttle Body Pipe Clamp

Loosen the hose clamp near the air filter:

Yukon/Tahoe Air Cleaner Pipe Clamp

And the tricky part, disconnect the keeper holding the tube to the coolant hose. Get a very small flat head screw driver to depress the lock and wiggle the keeper apart:

Yukon/Tahoe Keeper

Now pull out the assembly and you should see this:

Yukon/Tahoe Throttle Body

Push open the top of the throttle plate and you’ll see a thick layer of black carbon on everything. Get your carburetor cleaner and blast it on all the surfaces around the inside of the throttle opening (called the venturi.) Get your shop towel and while holding the throttle open, clean as far in as you can. Clean the back side of the the throttle plate (butterfly valve) as much as you can. Take some time here and make sure it’s spotless. Be sure to remove any fuzzles left by the shop towel. We don’t want them in the engine.

Yukon/Tahoe Throttle Body Areas to Clean

Put it all back together and make sure the engine starts.

That’s it!

For us: IT WORKED!

The erratic idle is gone, the stalls are gone. Unbelievable.

I’d give it a 1.5 on the difficulty scale. Anyone with a bit of mechanical skill should be able to do this fix.

GMC Vortec 6000 engine

You’ll need 8 spark plugs, anti-seize compound, a regular socket wrench, a socket adapter kit, spark plug socket, and probably a metal tube to slide over the socket wrench for more leverage. I used the steering shaft off the kids Razer scooter.

There are two challenges with this DIY. One is getting the spark plug boots off. They simply pop off when the boot is pulled, but they’re on there TIGHT, you may have to twist them to break free, then pull straight back. There’s a metal heat shield around them which gets in the way but there’s enough plug to grab on to. That shield will come off with the plug. One trick I used was to grab the rubber boot with some channel locks and pull them out using the manifold studs for leverage. This worked well for the passenger side plugs, especially for the one in the very back.

Spark Plugs Drivers Side

The sparks on the drivers side were accessible, but the steering shaft did make things more challenging.

Spark Plugs Drivers Side Steering Shaft

Spark Plugs Passenger Side

Spark Plugs Passenger Side Hard One In Back

After getting all the boots off the second challenge of getting the spark plugs out presents itself. This actually wasn’t that hard, but you had to be clever. I used the regular socket wrench with a combination of adapters to build extensions long enough to clear the engine, but short enough to avoid fire walls and steering columns. Frequently you could build a socket combination that worked, but couldn’t get leverage to turn the spark plug. That’s where the tubular extension came in handy. For the back passenger side plug I used a 3/8 to 1/4 drive adapter and another 1/4 back to 3/8 adapter to get just the right extension length.

After getting the plugs out, simply apply anti-sieze compound to the threads of the new spark plug, thread them in by hand, then tighten by had with the socket wrench. I don’t know the torque for the splugs, I’ve seen both 22 lbs/ft and 11 lbs/ft so I went with had tight. That should be OK.

On a difficultly scale of 1 to 10 I’d give it a four or five as you have to lean over the truck’s fender and really pull hard on the spark plug boots at weird angles around large obstacles. You need to be clever with a bunch of sockets extensions too. Finally, I pinched a nerve in my back which will take a week to clear up and combined with the upper body muscle soreness from having to pull and twist at wierd angles you’ll be in some pain for a while if you write software for a living.

Apparently, this is a very common problem that I’ve had a while. The fix is supposed cheap and easy and having done it once, the second time would be very easy. The Job took me about six hours with a lot of frustration the first time. Using these instructions you should be able to get it down to under two hours.

The parts used are:

• Napa red general purpose fluid hose in 1/2 and 5/8 ID sizes. The box they came in state they support 250 PSI which should be plenty.
• Four screw type hose clamps.
• A new P/S resevoir. The resevoir has some kind of filter in it so I decided to replace it too. They’re only about $25 online.
• One quart of Dextron IV ATF.
• Dremel.

To get the job done, I had to remove the entire air box/filter and the headlight. Removing the headlight’s a bit dodgy, but made the job possible. Some instructions are here: http://www.e46fanatics.com/how-tos/exterior/bmw_e46_headlight_trim/bmw_e46_headlight_trim.php, I’ve included them and some of my own additions here:

Removing the headlight assembly:

1. Pop the hood and remove your turn signal lens.  This is done by inserting a flat head screwdriver like so and pushing the tab towards the front of the car.
2. Next is removing the trim that runs underneath the headlight assembly.  Start by pushing the tab closest to the center of the car (first picture) and work across removing this piece.  Once you release the tab in the third picture, you are ready for the difficult part…
3. When you get to the tab that connects this piece to the fender, this will be the most difficult part of the procedure.  I used a couple of different techniques to release this tab.  On one side, I was able to sneak the flat head screwdriver behind the tab as pictured and push towards the front of the car to release the tab.  On the other side, that didn’t work so I had to take a small-tipped flat head screwdriver and weasel the tab open from the front side.  If you work with this tab enough, you should be able to get it off.
4. Remove the two screws holding the top of the assembly. Using a ratchet with eight inch extension, remove the screws holding the headlight assembly at the bottom rear, right and left of the assembly.
5. Disconnect the wires and the assembly should fall right out.
6. These headlight assemblies are unbelievably expensive. Put it in a VERY safe place.

Tips on replacing the hoses are as follows:

1. Cover your alternator with rags to keep ATF out of it.
2. Have a bowl hand to catch extra ATF as you dis-assemble the system.
3. Using your Pela oil extractor, extract all the oil out of the resevoir,
4. Disconnect the resevoir from the hoses, you may need the dremel to cut the factory clamps. Keep that bowl and extra towels handy.
5. Extract ATF from the hoses with the Pela.
6. Cut the factory clamp off the P/S pump with the dremel.

Here’s the hard part. On this connection:

..you need to dis-engage part 1.

A useless internal schematic is here:

You really should use BMW tool 5346:

…and considering you’re saving about $400 over the dealer price by doing this yourself, I’d probably buy it.

Unfortunately, the plastic release collar broke on my car so I cut off the whole thing with the Dremel.

Replace the hoses, fill the system with ATF, turn on the car, turn the wheels all the way right to left a couple/three times, refill and your done.

The process was pretty easy requiring a modest technical skill set and tools. I think most people can handle it. The real tricky part is threading the wire around the engine compartment but the help of a spouse or stick should be enough to complete the job.

Follow the instructions here at e46fanatics.com.  They’re priceless.

The result is the car’s much more responsive and fun to drive again.

For me, it was back to home oil changes. Luckily, bimmerparts.com has filters for less then $10 each so I buy three at a time and I buy the mandatory Castrol 5w-30 Syntec oil when it goes on sale. But that still leaves spending and afternoon jacking up the car and crawling underneath it ( a good time when you’re a teenager, but not later in life,) hoping you don’t strip the oil plug, spilling oil all over, etc.

While up on bimmerforums.com I heard people chatting about the Pela PL-650 oil extractor. I checked around and found a reasonably priced model at Yachtsee.com. I paid with PayPal and it arrived in a couple days.

The Pela PL-650:

The parts that come with it, the extractor, one base tube and two extension tubes of differing widths:

The pouring spout:

The pressure release valve:

It’s a simple but effective device with good build quality. To start, drive the car around so the oil heats up a bit. Stop and let the oil drip back into the sump. Open the filter housing and toss out the filter. Then simply attach the base hose of the Pela PL-650 to its tank and the narrow tube extension to the base and insert the narrow tube into the oil dip stick pipe. Pump the handle about five times and wait about fifteen minutes for it to extract all the oil.

When complete, disassemble and easily tip the unit over and pour the old oil out the spout into old milk containers.

It’s very effective. Typically I can go through the whole process without spilling a drop. The car requires six quarts of oil and when I have that in the sump, the Pela will get it all out. Best of all, I never have to crawl under the car or risk damaging the oil plug.

If you own and E46 BMW and change your own oil, I highly recommend one of these devices.

PS: Be sure to get the Pela PL-650. The others won’t extract the entire sump in one go. You’ll have to stop and re-start the extractions with the smaller models.

I thought it’d be great to get an engine code scanner and find out what the issue is myself, but after reading a bunch of articles, it wasn’t clear which one I should get. Apparantely, there is a standard code system called OBC-II that all the manufactuers support to one degree or another. BMW fully supports the spec, but then adds a ton of proprietary codes that they keep to themselves and as one guy said, “only lets the dealers see them on Christmas.”

Surfing around shows a lot of standard products, many of them claiming to decipher the elusive BMW codes. The most promising products are the Peake Research R5/FCX-3 and the AutoEnginuity Scan Tool. The Peake Reaearch product seemed a bit pedestrian but claimed to only support BMW automobiles, a good and bad thing. It only cost around $150 so it suited my needs a bit better than the seemingly full featured AutoEnginuity product for close to $500.

Peake sells their product online but want $150 and $8 to ship via the slow boat out of Guatemalla. I found EuroSportDesign but they came across as a bit too slick. Luckily, they have an eBay presence and sold the unit for $138 with fast shipping for $3. I can pay via PayPal. Sold!

The unit arrived in three days:

The contents: tool, case, and manual. The phone is there for a size reference. The R5/FCX-3 was smaller than I expected, simple, but adaquate construction. The manual was simply a photocopy.

The front:

The connector:

Installation was beyond trival: Turn on the car, then under the driver side dash is a panel. Flip it open and plug in the R5/FCX-3. You’ll quickly get this message meaning you’re ready to go:

Press ‘Go.’ Thinking a bit:

19 is the code page. Press ‘GO.’

76! Let’s see, that the throttle position sensor is amiss. Press ‘Go’ again:

41! Hmm, need a new intake camshaft position sensor. Press ‘Go’ again:

CC! Something’s hosed with the idle control. Press ‘Go’ again:

All done!

Was is worth it? Probably, if I use it twice it should more than pay for itself compared to dealer diagnostic rates. The nice thing about it is the size is small enough to keep in the car for freeway side diagnostics. Now it’s off to bimmerparts.com for new parts! Look forward to posts about replacing the above parts

So the whole family’s on the way to sign refinance papers in two cars so I can go back to work after we’re done. I hop in the BMW and out the garage. About 1/2 a block out, things don’t feel right. Two blocks out I feel something’s very wrong, like I’m missing teeth on the differential or something. I pull over and the passenger rear tire’s out. Bad news. Luckily, the wife, kids, and truck are only around the corner so I call them on the cell and they come back to get me.

This should be interesting as I haven’t changed a tire in a long time. Luckily, BMW makes it easy an painless to recover from these eventualities, you see, BMW’s sport a full size spare (sometimes on a premium wheel, like mine.) The shop lift I have in the garage won’t fit under the low slung 330i sport so I use the funny looking contraption jack that came with the car. It worked much better than I expected and had the tire changed in about seven minutes. Needless to say, the kids were very impressed.

A quick inspection revealed the problem, a huge screw in the middle of the tire. Much like this one:

I took it to the dealer and they couldn’t fix it because I’d damaged the side wall during my two blocks of driving, and the tread was too thin. WHAT! I’ve had these Pirellis for about 25,000 miles, they can’t be bad already!

There’s nothing I can do. The dealer won’t fix them and I need the car in top shape. So I head back to tirerack…

If these sport tires are only going to last 25,000 miles I’m getting something cheap. Good thing ’cause the same Pirelli’s are now $50 more, each, and out of stock.

That’s when I found General Tire. I don’t know anything about them, I don’t care. I just need cheap sport tires. So I picked a couple of these General Tire Exclaim UHPs for the rear of the BMW:

…Tire Rack got them to me a day early for less than $100 each. Good deal. Got them to the dealer and had them swapped out for another $100.

Brand new they they tracked (squirmed) around the road funny, but 4000 miles later they’ve settled down and feel like the Pirellis.

I didn’t change the front’s as they still had good tread on them, probably a total 50,000 miles worth. But when they go, I’ll probably get a couple more Exclaims.

Here’s how they look on the car:

The requirements were a cool brand, reasonable cost, 40K lifetime and some hope of grip in the snow.

It didn’t take long to land on the Pirelli P Zeros M+S. Ordering a set was painless from tirerack and they arrived on time. The local BMW dealer installed them for me.

What’s fun about owning a performance automobile is that you can instantly detect any change to the suspension. That was definetely true with these new tires. The old Yokohamas were stiff, sticky, and tramlined all over the place. I didn’t take long to learn what lanes of various freeways to stay out of. You’d swerve all over the place like a drunk with them The new Pirelli’s were great. They felt like a new pair of comfortable sneakers. There was no tramlining to speak of and were somewhat quieter than the old tires.

I did get some time in the snow with them and on a 330i sport with traction control, they’re worthless. Telecommute when it snows and you own these tires. I couldn’t even get up a modest lift in the road. It was a total disaster…

I started with the dawn wash then went into the clay bar. That clay bar makes the whole system worth it. It’s amazing. Even after a good wash, you can feel the bar take off another layer of crud. After cleaning half the hood, the bar’s surface was black with dirt. The bar was destroyed by at the end of the job.

I then applied Z2 Pro, buffed, then Z6. The car looks really good, but the final judgement will be in it longevity…

I just (an hour ago) finished washing, clay baring, and washing again the Yukon and it looks great. Those steps on a full size SUV took exactly three hours. Tommorow I’ll wax with Z5 to hide the swirls on the black paint, then Z6, then Z2, finally Z6. Stay tuned for pictures.

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