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Ok, I'm at a complete loss here. '01 325i m/t. Idle is bouncing coming to a stop (shift to N or clutch in). Drops down to about 500 or slightly under bounces back up to 900-1k and just continuously bounces the whole time unless I feather the gas a little and settle it at 700 myself. Sometimes it stabilizes itself, but even then it's after a drop to 500 and back up to maybe 800 before stabilizing. Replaced both intake boots, cleaned IAC then replaced IAC (I can hear it working when I turn key to on), replaced a few vacuum lines, air filter, fresh oil change, new MAF, new fuel pump and filter, rebuilt DISA. Smoke test can't find any leaks. No codes except SAP (plastic tube broke, temporarily capped on both ends). Had lean codes when I got it a few months ago, went away after MAF and boots. I haven't the slightest clue what else I can do. The two things I haven't gotten to yet are Vanos rebuild and CCV. I've tried running it with the MAF unplugged, no change in the issue.

Someone please give me some insight!!!
 

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Continue replacing vacuum hoses.

also caps (plugs) at the rear of the intake, another small vacuum hose there too. Mine were very deteriorated I didn't find those until the hard pipes job!:idea: More knowledgeable folks will chime in here.
 

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Use the "search this forum" for lean codes, yours is probably the 1000th thread on the subject. Start by going over the vacuum lines again, throttle body o ring, rubber connected to the ICV, DISA o ring, SAP rubber bits, back of manifold where SAP line connects and CCV.
 

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Discussion Starter #4
also caps (plugs) at the rear of the intake, another small vacuum hose there too. Mine were very deteriorated I didn't find those until the hard pipes job!<img src="http://s1.E46Fanatics.com/forum/images/smilies/thinkerg.gif" border="0" alt="" title="Idea" class="inlineimg" /> More knowledgeable folks will chime in here.
I replaced the cap and the hose. Mine doesn't have the small cap portion from what I can tell. I will definitely take another look (or feel, rather).
Use the "search this forum" for lean codes, yours is probably the 1000th thread on the subject. Start by going over the vacuum lines again, throttle body o ring, rubber connected to the ICV, DISA o ring, SAP rubber bits, back of manifold where SAP line connects and CCV.
I have searched and read through dozens of the threads. I do NOT have lean codes. I've already replaced all the things you've mentioned except for the TB gasket (sprayed with no effect) and the CCV. CCV is next on the list, but I haven't seen any information as to what the symptoms would be in relation to the idle aside from "poor" or "rough".
 

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Discussion Starter #10
What was the air pressure of the smoke machine?
Not too sure honestly. It was a buddy's diy job.

I did, however, replace the vacuum lines from the SAP to the control valve to the intake, the caps, and had previously replaced pretty much every other vacuum line. I gave it another smoke test, and went through three cans of carb cleaner. Sprayed down TB, IAC, intake flange, all vacuum lines I could get to (even most all of it behind the intake, SAP and valve, as much of the CCV hoses I could get the spray to, DISA... Probably some other stuff. I cannot find a vacuum leak ANYWHERE. I will say, replacing all the hoses DID help the issue, but very minimally. It still has the dip down to 500+/-, but it stabilizes easier now. I didn't have to feather the gas for it to stabilize. Ran the AC on the way home, seemed to even out better there too, but still surged enough to be annoying. Kicked the headlights on with the AC so it would have a fair load and it did surge like hell in that scenario, about as bad as before.

I guess I'll continue with new CCV, hoses, and Vanos rebuild. Also, I've read in a couple of threads something about an software update for the DME that address a similar issue. Anyone have any details about that?
 

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Forget about the VANOS and DME updates, if the DME was an issue and needed to be updated, the problem would have happened 10+ years ago.

Fuel Trim values?? Don't have an OBDII tool, you NEED one. OBDFusion is what you want, search my user name, PLENTY of info.

Read the first post in this thread at least 3 times: Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Smoke testing WILL NOT find a bad power brake booster. Crankcase air leaks require the oil fill cap to be removed so all the air can be purged out of the crankcase.

Clean the ICV.
 

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Discussion Starter #12
Forget about the VANOS and DME updates, if the DME was an issue and needed to be updated, the problem would have happened 10+ years ago.

Fuel Trim values?? Don't have an OBDII tool, you NEED one. OBDFusion is what you want, search my user name, PLENTY of info.

Read the first post in this thread at least 3 times: Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Smoke testing WILL NOT find a bad power brake booster. Crankcase air leaks require the oil fill cap to be removed so all the air can be purged out of the crankcase.

Clean the ICV.
That makes the fourth time that I've read through that actually, lol. Most of it pertains to lean codes, which I replaced many of those things when I resolved my lean codes.

I have Torque Pro, I'll log some fuel trim readings tomorrow. I'll take a look/listen to my brake booster as well tomorrow. I have cleaned my ICV twice, now replaced. I still basically left with CCV, VANOS (reportedly can cause idle problems), brake booster...

From my reading about the DME update, a few folks are saying that it did help idle coming down from high RPM. I don't really expect it to FIX my issue, but maybe at least help a little.
 

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Hiya.

I had similar issues on my 325 when I first got it, including occasional CELs and really rough idle when cold
.
I haven't yet completely stopped this "hunting" behaviour, but it's now extremely rare.
I've done everything you've described, but have also replaced the CCV, throttle body gasket and inlet manifold gasket.

I've still got a leaking valve cover gasket to replace (leaks oil onto the exhaust), and intend to replace the oil filler cap gasket and the o-rings on the "distribution piece" and also injector o-rings. I'm hoping this will finally stop the hunting.

None of these parts are expensive, but I found the CCV to be particularly difficult. It would have been much easier if replaced at the same time as the inlet manifold gasket.

Good luck!
 

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Discussion Starter #14
That makes the fourth time that I've read through that actually, lol. Most of it pertains to lean codes, which I replaced many of those things when I resolved my lean codes.

I have Torque Pro, I'll log some fuel trim readings tomorrow. I'll take a look/listen to my brake booster as well tomorrow. I have cleaned my ICV twice, now replaced. I still basically left with CCV, VANOS (reportedly can cause idle problems), brake booster...

From my reading about the DME update, a few folks are saying that it did help idle coming down from high RPM. I don't really expect it to FIX my issue, but maybe at least help a little.
Here are the log files I was able to get today with Torque Pro. Now, I've not logged with this before, so I don't know if I got all of them right or which aren't even accurate. Let me know if you need something different, and if so how to get that done.

https://drive.google.com/file/d/1fkIl0IjaitNud2a_4ulHc91lRrgmSWLt/view?usp=sharing

Hiya.

I had similar issues on my 325 when I first got it, including occasional CELs and really rough idle when cold
.
I haven't yet completely stopped this "hunting" behaviour, but it's now extremely rare.
I've done everything you've described, but have also replaced the CCV, throttle body gasket and inlet manifold gasket.

I've still got a leaking valve cover gasket to replace (leaks oil onto the exhaust), and intend to replace the oil filler cap gasket and the o-rings on the "distribution piece" and also injector o-rings. I'm hoping this will finally stop the hunting.

None of these parts are expensive, but I found the CCV to be particularly difficult. It would have been much easier if replaced at the same time as the inlet manifold gasket.

Good luck!
Thanks for the info Si. I've been getting a pretty rough idle on cold start lately too. Also, I just started getting a "belt squeak" from up front. Pulley and/or belt will be replaced soon, along with CCV and VANOS rebuild. I sprayed the hell out of the TB and didn't get any response to pinpoint a leak there. I do still have the P0491 and P0492 codes.

I'll look into the o-rings for the distribution piece and the oil cap seal. I'm not aware of any oil leaks, but it's difficult to tell for sure given that my PS leaks like crazy. I'll probably take the preventative measures and replace the OFHG, TB gasket, dipstick o-ring, and any other rubber bits that I'm coming close to during the CCV/VANOS job. May even just go buy some silicone vacuum line and replace them ALL at the same time. Can the plastic tubes to the SAP and the FPR be replaced with silicone or do they need to stay "hard" piped?
 

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MAF reading looks pretty bad. Most of these engines have a MAF reading of around 3.4-4.2 g/s at 700 RPM in park or neutral without other loads.

Low MAF values are either due to post MAF air leaks, do not forget about the brake booster you cannot smoke test it easily for leaks, or an under reporting MAF due to either a counterfeit Asian cheap knock off or a contaminated MAF that you cannot clean.

Really prefer OBDFusion over Torque Pro. OBDFusion is only $3.99 and will work with your current interface.

Suggest you read this:

Suggest you also read the PDF in this thread for more details about how to capture and share the data - http://forum.e46fanatics.com/showthread.php?t=1097893 This info is Android specific, iProducts is similar, menu options may be different.
 

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Discussion Starter #16
MAF reading looks pretty bad. Most of these engines have a MAF reading of around 3.4-4.2 g/s at 700 RPM in park or neutral without other loads.

Low MAF values are either due to post MAF air leaks, do not forget about the brake booster you cannot smoke test it easily for leaks, or an under reporting MAF due to either a counterfeit Asian cheap knock off or a contaminated MAF that you cannot clean.

Really prefer OBDFusion over Torque Pro. OBDFusion is only $3.99 and will work with your current interface.

Suggest you read this:

Suggest you also read the PDF in this thread for more details about how to capture and share the data - http://forum.e46fanatics.com/showthread.php?t=1097893 This info is Android specific, iProducts is similar, menu options may be different.
I'll read through that. I bought OBDFusion the other day as well, just haven't had any time to play with any of it yet.

I did roll up the windows and turn the AC/radio off, listened to the brake booster, but didn't hear anything that matched the descriptions given. No air flow sounds, not even really any hiss on pedal depression. I could probably at least throw a new booster hose and grommet on it and see if any symptoms change.

The MAF has been replaced a couple times. Replaced it originally due to MAF codes and lean codes. Bought a Bremi replacement new, and it caused stalls and far far rougher running than the OE bad one. Went to local junkyard and grabbed one off a parts car there, cleaned it, replaced it and no MAF codes since. Lean codes went away after that and intake boots. So I suppose there's a chance that it's also just faulty and not able to be cleaned, but there are not, not have there been, any MAF CEL since it was replaced.
 

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Not sure about the SAP pipework - I don't have one!
I'd presume that silicone vacuum lines would be an upgrade though.

Might also be worth double checking the DISA o-ring, as I rushed it when rebuilding it and didn't fully remove the old built-in gasket.:facepalm:

Did you get a chance to check the vacuum take-offs / caps at the back of the inlet manifold yet? (against the firewall)
 

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Not sure about the SAP pipework - I don't have one!
I'd presume that silicone vacuum lines would be an upgrade though.

Might also be worth double checking the DISA o-ring, as I rushed it when rebuilding it and didn't fully remove the old built-in gasket.:facepalm:

Did you get a chance to check the vacuum take-offs / caps at the back of the inlet manifold yet? (against the firewall)
I did replace the o-ring when I rebuilt the DISA. Checked it the other day with carb cleaner and seems to be leak free. I do, however, need to check again that my DISA is functioning properly. I know it can cause these issues as well and I haven't checked the vacuum on it since I rebuilt it. Could've crapped out I suppose. I would like to delete my SAP all together, just don't want the CEL perm lit.
 

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A few things.

Do not post a .XLS file, I only want .CSV file.

Your 2001 325ci DOES NOT have Wideband O2 sensors so forget about those. If you are following the guide I put together, I ask for these because I never know the model or year of the car, so I ask for too much so I get everything on the first attempt.

If you are having issues, restart your phone and see how things play on a fresh restart. Chances are there may be some conflicts or something running in the background unless your phone is taxed out due to lack of procession power and RAM. Often you may need to kill background processes or even put the phone is Airplane mode and only turn on Bluetooth and kill any other Bluetooth devices that are in and around the car.

I will not be able to review anything tomorrow, I will busy most of the day.
 
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