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<blockquote data-quote="jaleeks23" data-source="post: 438164" data-attributes="member: 8431"><p>Read this in another forum :- <a href="http://forum.e46fanatics.com/showthread.php?t=342081" target="_blank">http://forum.e46fanatics.com/showthread.php?t=342081</a></p><p>Another simple DIY to learn I think...</p><p></p><p>Last week while sitting in rush-hour traffic I noticed my car was idling terribly. The problem was traced down to an adjuster unit in the intake manifold that had broken. $206 in parts later the problem seems to be fixed. I can't say this is causing everybody's problem, but based on the part and the problem I believe it is prudent for all fanatics to check this part on a regular basis. Details follow...</p><p></p><p></p><p>Car</p><p>2004 330Ci, 04/2003 Build, 86,660 Miles</p><p>Manual Transmission</p><p>New Bosch Coils installed around 50k Miles</p><p>New Spark Plugs installed around 80k Miles</p><p></p><p>Symptoms</p><p>Initially the car was idling roughly and the MIL (aka CEL/SES) light was off.</p><p>Car idled roughly regardless of cold or hot.</p><p>When the MIL did trip the codes were as follows</p><p>Misfire - Cylinder 1</p><p>Misfire - Cylinder 2</p><p>Misfire - Cylinder 3</p><p>Misfire - Cylinder 4</p><p>Misfire - Cylinder 5</p><p>Misfire - Cylinder 6</p><p>Misfire - Multiple Cylinders</p><p>System Too Lean (Bank 1)</p><p>System Too Lean (Bank 2)</p><p>MAF Sensor (can't remember the exact code)</p><p></p><p>Diagnosis</p><p>* Since the MIL originally wasn't on when the problem started, I took the car to a shop to have all fault codes read.</p><p>* The mechanic at the shop found the adjuster unit was broken, but was convinced the problem was vacuum-related.</p><p>* Mechanic tried other diagnostics, such as moving plugs and coils around, with no luck.</p><p>* It was getting late so the mechanic pulled the broken adjuster unit flap out of the intake manifold and put the adjuster unit back in.</p><p>* While driving home the "System Too Lean" codes were set. These did not happen while the car was in the shop.</p><p></p><p>Commentary & Lessons Learned</p><p>I still don't have a definitive understanding of what the adjuster unit does. However, based on the location of the part (the flap portion goes inside the intake manifold), I'm guessing the relative position of the flap determines how much air the engine gets. When the mechanic pulled out the broken flap, the unit was left wide "open", which I'm guessing caused the "System Too Lean" condition.</p><p></p><p>After inspecting the broken flap and the unit more closely, I noticed there was significant dirt build-up on the parts (see picture). I'm guessing over time this build-up eventually started restricting the flap's movement. Since the flap is connected by a plastic connecting piece, the excess build-up ultimately caused the plastic connecting piece to break and the part to fail.</p><p></p><p>I drove the car for several miles today after repair and noticed that the idle was smoother and also the throttle response was quicker. I believe prior to the part's failure the adjuster unit flap's operation was still restricted which caused incorrect air/fuel mixtures to be running through the engine when engine speed was changing. For example, RPMs tended to drop more slowly before the rough idle problem appeared.</p><p></p><p>Based on the amount of dirt that was on my adjuster unit, I believe this part may be responsible for more than just rough idle problems (and possibly stalling on steptronic cars). Since the adjuster unit is a physically moving part, there is no easy way for the computer to know that it's gone bad, other than throwing other errors. The adjuster unit is a fairly expensive part ($200), so it would probably be a good idea to pull it out every Inspection to inspect and clean. Also, it appears there is a small metal pin holding the far end of the flap, if the adjuster unit fails it's possible this small metal pin will end up somewhere in your engine. Preventative maintenance of this part is key.</p><p></p><p>EDIT: Looking closely at the second picture, it looks like the adjuster unit is made to be able to close 100%. With all the dirt deposits on the second picture, it looks like the adjuster hasn't been fully closed for a while. This might be causing some of the intermittent idle problems. Just an afterthought...</p><p></p><p>DIY Notes</p><p>Removing the adjuster unit requires two T40 Torx screws to be removed and then the unit can be pulled straight out. However, due to space constraints I recommend removing the airbox to allow you to push the intake hose down to give more room to remove the valve. When you pull the unit out you will have to angle it slightly upwards to remove. Installation is the opposite of installation, you will need to insert at an angle to get it to fit, it helps to hold down the intake hose.</p><p></p><p>The DIY Disclaimer</p><p>It wouldn't be a DIY without one! I make no warranties to the accuracy of this information or my commentary/beliefs nor do I take any responsibility to update this information should additional details arise. I take no responsibility for any problems you run into for following any of this information. If you are uncomfortable with working with your own car please seek advice from a professional mechanic.</p></blockquote><p></p>
[QUOTE="jaleeks23, post: 438164, member: 8431"] Read this in another forum :- [url]http://forum.e46fanatics.com/showthread.php?t=342081[/url] Another simple DIY to learn I think... Last week while sitting in rush-hour traffic I noticed my car was idling terribly. The problem was traced down to an adjuster unit in the intake manifold that had broken. $206 in parts later the problem seems to be fixed. I can't say this is causing everybody's problem, but based on the part and the problem I believe it is prudent for all fanatics to check this part on a regular basis. Details follow... Car 2004 330Ci, 04/2003 Build, 86,660 Miles Manual Transmission New Bosch Coils installed around 50k Miles New Spark Plugs installed around 80k Miles Symptoms Initially the car was idling roughly and the MIL (aka CEL/SES) light was off. Car idled roughly regardless of cold or hot. When the MIL did trip the codes were as follows Misfire - Cylinder 1 Misfire - Cylinder 2 Misfire - Cylinder 3 Misfire - Cylinder 4 Misfire - Cylinder 5 Misfire - Cylinder 6 Misfire - Multiple Cylinders System Too Lean (Bank 1) System Too Lean (Bank 2) MAF Sensor (can't remember the exact code) Diagnosis * Since the MIL originally wasn't on when the problem started, I took the car to a shop to have all fault codes read. * The mechanic at the shop found the adjuster unit was broken, but was convinced the problem was vacuum-related. * Mechanic tried other diagnostics, such as moving plugs and coils around, with no luck. * It was getting late so the mechanic pulled the broken adjuster unit flap out of the intake manifold and put the adjuster unit back in. * While driving home the "System Too Lean" codes were set. These did not happen while the car was in the shop. Commentary & Lessons Learned I still don't have a definitive understanding of what the adjuster unit does. However, based on the location of the part (the flap portion goes inside the intake manifold), I'm guessing the relative position of the flap determines how much air the engine gets. When the mechanic pulled out the broken flap, the unit was left wide "open", which I'm guessing caused the "System Too Lean" condition. After inspecting the broken flap and the unit more closely, I noticed there was significant dirt build-up on the parts (see picture). I'm guessing over time this build-up eventually started restricting the flap's movement. Since the flap is connected by a plastic connecting piece, the excess build-up ultimately caused the plastic connecting piece to break and the part to fail. I drove the car for several miles today after repair and noticed that the idle was smoother and also the throttle response was quicker. I believe prior to the part's failure the adjuster unit flap's operation was still restricted which caused incorrect air/fuel mixtures to be running through the engine when engine speed was changing. For example, RPMs tended to drop more slowly before the rough idle problem appeared. Based on the amount of dirt that was on my adjuster unit, I believe this part may be responsible for more than just rough idle problems (and possibly stalling on steptronic cars). Since the adjuster unit is a physically moving part, there is no easy way for the computer to know that it's gone bad, other than throwing other errors. The adjuster unit is a fairly expensive part ($200), so it would probably be a good idea to pull it out every Inspection to inspect and clean. Also, it appears there is a small metal pin holding the far end of the flap, if the adjuster unit fails it's possible this small metal pin will end up somewhere in your engine. Preventative maintenance of this part is key. EDIT: Looking closely at the second picture, it looks like the adjuster unit is made to be able to close 100%. With all the dirt deposits on the second picture, it looks like the adjuster hasn't been fully closed for a while. This might be causing some of the intermittent idle problems. Just an afterthought... DIY Notes Removing the adjuster unit requires two T40 Torx screws to be removed and then the unit can be pulled straight out. However, due to space constraints I recommend removing the airbox to allow you to push the intake hose down to give more room to remove the valve. When you pull the unit out you will have to angle it slightly upwards to remove. Installation is the opposite of installation, you will need to insert at an angle to get it to fit, it helps to hold down the intake hose. The DIY Disclaimer It wouldn't be a DIY without one! I make no warranties to the accuracy of this information or my commentary/beliefs nor do I take any responsibility to update this information should additional details arise. I take no responsibility for any problems you run into for following any of this information. If you are uncomfortable with working with your own car please seek advice from a professional mechanic. [/QUOTE]
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