E46 fault codes 227, 228 and intake boot replacement
 

So if you've seen my "cheap E46" thread here, you've seen that I bought a super high mile questionable maintained 1999 328i. Why? Because I'm an idiot. But that's beside the point.

Because I have the cool Bavarian Technic scan cable, I scanned the car prior to purchase and found the following:

Attachment 49783

The lambda codes (227 and 288 esp) almost always point to a lean condition in the engine. During inspection of the car, the PO showed me this:

Attachment 49785

which matched up with the internet's diagnosis of the problem. Other posters also indicated that I would hear a weird, digital sounding buzzing that was throttle dependent when I drove the car - and sure enough I did. The problem is that air is getting into the intake AFTER the MAF, so that air is unmetered. Unmetered air = lean mixture, as the DME is only injecting enough fuel for the air is knows about (the air that went through the MAF properly).

Happy that the cracked boot was the issue I bought the car, ordered a new boot ($14 from BMW), cleared the codes (and thus the CEL), installed and test drove. The buzzing noise is still there, and within 3 miles the CEL is back on. :grrr:. Another scan shows codes 227 and 228 are back.

So, more investigation. Well, it turns out that there are TWO intakes boots after the MAF and both are susceptible to cracking. You can see them here in this diagram. The first boot boot (3) connects from the MAF to a hard elbow; this is the one I found in the initial inspection and replaced. The second boot (5) connects from the elbow to the throttle body.

Attachment 49784

Sure enough, it was cracked as well. This one was $16 and in stock from BMW of Rockville. Sweet! Hopefully I'll just throw this on real quick and problem solved! Here it is in all it's glory:

Attachment 49786

"Real quick". Hahahaha. I've said before that "E46s are easy to work on". I am now officially amending that to add the word "usually". Replacing that second boot was a PITFA. Why? Well what should be an easy unclamp-remove-replace-reclamp procedure is complicated by the location of the throttle body in the E46:

Attachment 49787

That's it - way back there behind all that shit. The red arrows point to the main throttle body and some secondary intake hose, both of which the new boot must be clamped to. The best part? The clamps that are on there were clearly installed during manufacturing when the engine was out of the car. Meaning the clamps themselves were completely in "f**k you" position for removal. Here you can sort of see the clamps - and this is AFTER I've cut most of the old boot away for access and visibility.

Attachment 49788

The red arrow points to the secondary intake clamp (facing backwards, because BMW engineers hate you) and the blue arrow points to where the main intake clamp is (again because the engineers hate you). After some more cutting and a not-insignificant amount of swearing, I got both clamps off and the old boot out:

Attachment 49789

Now - HTF is this thing going back in? I had to cut most of the old boot away to get to the clamps. Clearly that's not an option for reinstall. After more swearing and possibly breaking a few things in frustration, I found that the following clamp orientation allowed me to tighten the clamps without pulling the engine. First the secondary intake:

Attachment 49790

and then the primary intake:

Attachment 49791

Success!!!! Holy shit that was annoying. Fortunately the rest of the intake goes back together quickly and easily and voila! Ready to drive.

Attachment 49792

Nothing an engineer can't figure out! :-)

FWIW had similar issues on the Volvo, and even on the Targa. Some clamps, etc. clearly installed when access was not blocked by a ton of other stuff...

After reinstall I took the car out for a long drive and everything was perfect. 40 miles - stop and go traffic, highway speeds, etc - everything perfect! No CEL, no codes, and the weird buzzing/chirping sound is gone. Yeah!!! Come home, grab food and my son. "C'mon, you're learning to drive stick. Let's go".

About 15 minutes into the lesson, the CEL comes back on. Damnit!! I had the laptop and BT cable in the car, so I did a scan. Yep - 227 and 228 are back. WTF?

Well, if you were observant in the last picture of the first post, you probably noticed something:

Attachment 49793

The primary boot and the MAF are not attached correctly. I took this picture AFTER my driving lesson with my son, as I forgotten to take an "after" pic immediate after the reinstall. What happened three things:

1. The bottom of the air box wasn't installed correctly in the big rubber holder underneath it. Because the air box is missing a mounting tab, I attributed it's weird angle to the missing tab and not the misaligned bottom pin.

2. I didn't tighten down the MAF-to-boot clamp tightly enough

3. I was teaching a teenager to drive stick for the first time. Which meant lots of bucking and stalling of the engine.

So I'm pretty sure the MAF-to-boot connection opened itself up during the driving lesson and threw the codes again. Yesterday I pulled the airbox, reinstalled correctly, tightened the clamp properly and tested again. Again 40 miles, again no issues.

Then I took my daughter out on her first manual transmission excursion. 45 minutes of nausea-inducing driving later, still no codes. Crossing fingers, but hopefully this has fixed the problem.

You didn't do the uber fun project of replacing the hoses under the intake. http://blog.bavauto.com/8003/diy-vid...lation-system/ They sell a kit, the one with the "cold weather kit". You live around here, it's warm enough. Throw that cold weather insulation a way. This was one of the most frustrating automotive experiences I've had (and recall I own a 944). Try and clip two plastic hoses together under the intake where you cannot see it.

That project?

Attachment 49794

JazzBass,

I was confused by this a bit as I had boot and air leak problems which yielded 0171 and 0174. Also, I recently had issues with these codes which turned out to be a TPS problem. A quick search on e46fanatics shows the following:

P0226 Throttle/Pedal Position Sensor/Switch C Circuit Range/Performance Problem

P0227 Throttle/Pedal Position Sensor/Switch C Circuit Low Input

P0228 Throttle/Pedal Position Sensor/Switch C Circuit High Input

What I found out is that these cars have a Hall Effect TPS on the gas pedal and (one or two mechanical variable restor types on the MAF. More than likely the issue is the mechanical restor type. Having said that, does you car still have the throttle cable? Anyway something to check.

Dumb question: Unplug the connectors to the MAF and the throttle body?

Should be "Did you unplug"

If I remember correctly, some early e46s still had throttle cables.

http://forum.e46fanatics.com/showthr...ight=p0227+cel This may help.