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Old 01-18-2013, 03:49 PM   #1
JakeEppehimer
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Join Date: Jan 2013
Location: Ruston, LA
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My Ride: 2001 330Ci
Erratic idle, worse in cold weather. Very unusual symptoms. Ready for a challenge?

Ok, I've tried my hardest to find info online and solve this problem myself, but I can't seem to get it. I hope you will be willing to read all of this and help me because I just CANNOT find the root cause. Just to put it into perspective, I'm a Mechanical Engineer working in the auto industry. I'm not insanely experienced, but I know what I'm doing. I'm also capable of extensive research, and I can't find much help. This seems to be a very complicated issue.

In summary, for over a year, my car (2001 330Ci, now with about 135k miles) has had an occasional oscillating idle. Most of the time it will have this issue immediately when I press in the clutch and remain in neutral right after an RPM above 3000, rather than shifting into another gear. There are NO issues when the car drives.

Going further... about a year ago, I thought I could solve the problem with a tune-up. I replaced the spark plugs, fuel filter, both precat O2 sensors, and ran some Lucas fuel injector cleaner. The car needed this, but it didn't fix the problem. I didn't get enough free time until last summer of 2012 to work on it again. It became more pressing because my car had severe oscillation issues on my way to my first day of work... Imagine my frustration. It was stalling out, check engine light flashing, and it was just... horrible. I managed to lurch the last half mile to work. Strangely, the problem went away that afternoon when I started it up. I decided to try cleaning the idle control valve in case it would prevent future issues. While doing that, I found this:



So you know... figured it couldn't hurt to replace the intake boot while I was at it... I replaced it and also cleaned the ICV with carb cleaner. The car ran more smoothly and I didn't have serious issues for a while, but it still had the erratic idle. I didn't have much free time to troubleshoot, and I read online that it's common, so I left it alone for a while.

Then about a month ago, the car started running exactly the way it did when I forgot to plug in a coilpack... I knew one of the cylinders wasn't firing. Sure enough, I pulled a code P1349 - Misfire cylinder 4 with fuel cutoff. When I restarted the car, it no longer had the issue. I tested the coilpack with a multimeter and it seemed fine. Also replaced it with a new one, but idk if it made a difference because the issue was no longer present. I put the old one back in and returned the new one, so it is POSSIBLE that it could be the issue... They're just so damn expensive to replace if unnecessary! Strangely, this happened the day after I changed the air filter... It was running GREAT right after the filter change, but not the next day. Not knowing what else to do, I ran a bottle of Seafoam in the gas tank. It seemed to help. Also, the misfire issue has happened three times total, all solved by restarting the car. Then the check engine light goes off in a few days. The check engine light comes on and goes away occasionally with no apparent issues.

Now the current issue... still very similar, but lately it has gotten pretty cold for Louisiana. When there is cold weather, my car has much more trouble idling properly, and I can hear and feel the issue BIG time. The issue is sometimes present in warm weather, but it is almost always present and MUCH worse in the cold. Never has trouble starting, never stalls, doesn't have a problem driving... just crazy idle. I have checked all of the immediately apparent hoses for vacuum leaks... they all seem fine. And as I mentioned, I inspected the intake components over the summer when cleaning the ICV.

Here's what I'm thinking, and I want some advice regarding these and possible issues I haven't addressed:

-I want to replace the Vanos seals. I know this needs to be done, but it will be a huge amount of work. I wont have time for another month and a half. So I'm hoping a simpler fix could do it.

-I have heard about issues with the DISA box... But I don't really understand.

-Maybe there are some hoses with leaks that require some wrenching to see? I have not performed a smoke test.

-Maybe there is an electrical issue somewhere, since the misfire issue is able to be solved by restarting the car.

ANY HELP WILL BE EXTREMELY APPRECIATED!

Thank you,
Jake
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Old 01-18-2013, 03:55 PM   #2
WDE46
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The DISA flap can be inspected easily. Basically it becomes loose on a joint that actuates it and it flops around. Your problem doesn't sound like that though. The DISA has another issue where the O-ring leaks air, that could be a contributor. See if unplugging the MAF makes it run smooth. This will make the car run in open loop. It won't really solve anything, but you'll know your car is capable of running smoothly. It doesn't mean the MAF sensor is bad if this works. It would indicate a probable vacuum leak.

What codes are coming up other than the misfire?
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Old 01-18-2013, 04:18 PM   #3
JakeEppehimer
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Interesting... Why would it run smoothly with the MAF unplugged?

I only had that one code pulled. I do not have my own reader, so that was just what I got from borrowing a reader at AutoZone.
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Old 01-18-2013, 06:06 PM   #4
petemo94
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So you replaced the upper intake hose bc it was cracked. Why not go a step further and replace the lower intake hose? There's a good probability that its cracked bc it's closer to a heat source and most likely dry rotted.

I'm going to inspect mine soon but I heard getting it off is tough due to the access to the screw holding the band on it. Would advise you to pick up a flexible head screw driver / socket to get after it.

Report in what you find. Thx
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Old 01-18-2013, 06:26 PM   #5
JakeEppehimer
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I checked the lower boot when I was cleaning the ICV. It's surprisingly fine. But you're right, HUGE pain in the ass to remove. I changed the configuration of the clamps when I reinstalled it so that it would be simpler to remove in the future.
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Old 01-18-2013, 08:19 PM   #6
petemo94
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The ultimate test is to smoke test your intake. This will give you an idea of what this is about. I personally like the cigar smoke test. I think it's on page 4. Guys a hoot.

http://forum.e46fanatics.com/showthr...181&highlight=
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Old 01-19-2013, 07:18 PM   #7
Nersa
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Quote:
Originally Posted by JakeEppehimer View Post
I checked the lower boot when I was I changed the configuration of the clamps when I reinstalled it so that it would be simpler to remove in the future.
lol did the same thing last time i worked on these boots
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Old 01-19-2013, 07:27 PM   #8
JakeEppehimer
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Haha. Well, the past three days have been warmer weather, and she's been running great. When the issues come back, like I know they will, I'll try the MAF test. I'll also try the smoke test when I get a chance. But the real question, do you think the engine will be able to withstand another month and about 1000 miles before I can do some work on the vanos? I feel like that could be the issue. If you disagree, please let me know. But either way, I've never done it in the 3 years and 35,000 miles I've owned the car, and there's no telling when it was done last... so I should just go ahead and do it.
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Old 01-19-2013, 08:03 PM   #9
jfoj
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Suggest you read the first 2 links below in my signature as well as these threads -

http://forum.e46fanatics.com/showthr...ghlight=report

http://forum.e46fanatics.com/showthr...light=monitors

As I mention a few places, although VANOS seals are worth changing, I believe many of the cold start problems are really valve cover leaks that are resolved when changing the VANOS seals.

You also need a scan tool that can read real time data like fuel trims and possibly graph O2 sensor data.
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Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temps, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose fan switch O-ring - BMW #13621743299
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Old 03-10-2013, 06:16 PM   #10
JakeEppehimer
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To anyone who was helping on this issue, here is the latest info:

http://forum.e46fanatics.com/showthr...9#post15237089

I decided to hold off on the VANOS work, since it isn't a very likely contributor, I don't think. But could anyone tell me, do the VANOS seals need to be replaced EVERY 60k miles, or was that just for the factory seals?
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