Jazzbass
01-18-2016, 01:57 PM
So if you've seen my "cheap E46" thread here (http://dorkiphus.net/porsche/showthread.php?t=35676), 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:
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:
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.
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:
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:
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.
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:
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:
49790
and then the primary intake:
49791
Success!!!! Holy shit that was annoying. Fortunately the rest of the intake goes back together quickly and easily and voila! Ready to drive.
49792
Because I have the cool Bavarian Technic scan cable, I scanned the car prior to purchase and found the following:
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:
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.
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:
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:
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.
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:
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:
49790
and then the primary intake:
49791
Success!!!! Holy shit that was annoying. Fortunately the rest of the intake goes back together quickly and easily and voila! Ready to drive.
49792