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General E46 Forum
This is the place to get answers, opinions and everything you need related to your E46 (sedan, coupe, convertible and wagon) BMW!

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Old 08-07-2015, 10:28 AM   #1
sportwagenmann
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Join Date: May 2013
Location: Florida
Posts: 5
My Ride: 2002 325it
Need help on diagnosis!

I have an 02 325it, with 145k miles. Have owned since 04. In the last several months it has been exhibiting a problem I have not been able to diagnose. When warm, if I am stopped in traffic for more than a couple of minutes, the rpm drops to around 500, and the idle becomes erratic and very rough. If I sit for much longer after this begins, when the light turns green and I start to move, it becomes bizarre. It's almost as if it has lost several cylinders, it has NO power, you can literally depress the gas completely, and the top speed may be 20mph. It literally will not go. I usually pull off to the side of the road quickly so as to not irritate anyone behind me and shut the motor off, and wait for 30 seconds and re-start. It usually clears itself and runs ok, until the next traffic light where if I sit for any amount of time, it will do the same thing. I have looked through many threads to see if the same thing is happening elsewhere and cannot find the exact symptoms. I have been to Autozone to get fault codes read, to no avail. I have had my mechanic look at it and he can't get any fault readings either. Any suggestions would greatly be appreciated. Thanks.
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Old 08-07-2015, 10:35 AM   #2
jfoj
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Location: Fairfax, VA USA
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My Ride: 330CiC, M5, X5, E93
Time to gather data. Sounds like misfire with Fuel Cut Off that is cleared when restarting the engine.

Read away:

Get an OBDII smart phone/tablet App and interface, typically $30 or less. These Apps are usually best for drivability issues and they support Emission Readiness Monitor Status, Freeze Frame and Live/Realtime data. They are also great for Logging data for review after the car has been driven and can really help find unusual problems.

Android - Touch Scan for $3.95 and ELM327 OBDII to Bluetooth interface.

iProduct - OBD Fusion for $9.95 and ELM327 OBDII to Wifi interface.

I usually suggest getting the OBDII interfaces from Amazon if you are located in the US/North America. Make sure you choose an interface that indicates that the order will be "Fulfilled by Amazon" otherwise you may be waiting for WEEKS for an interface to arrive from Asia. Ebay is another option, but pay attention where the interface will be shipped from, again weeks for an interface from Asia, so if you can wait and want to try to save some money, go for it, but if you need an interface soon, choose wisely.

Read the 2 links below:

http://forum.e46fanatics.com/showthread.php?t=897616

http://forum.e46fanatics.com/showthread.php?t=929501

Need to see Freeze Frame info if the SES/CEL/MIL is on and Fuel Trim values at both warm idle and a steady highway cruise between 45-60 MPH.

MAF issues, first cleaning a MAF RARELY resolves anything, the only thing it usually cleans is your wallet.

If you have recently replaced the MAF, put the original back on the engine until you sort out all of the obvious issues. There are MANY counterfeit MAF's on the market and the major trap is ASSUMING the MAF is not the problem since it was recently replaced. Also quite often the MAF is NOT the cause of idle related Lean conditions and misfires, faulty MAF's usually under report the airflow as a percentage and are more of a problem at highway cruise speeds and not engine idle.

Unplugging the MAF will often cause the engine idle to be smoother, reduce or eliminate idle misfires. This DOES not mean the MAF is bad, it is due to the DME going into a fixed fuel Map mode that is typically by default Richer than when the MAF is connected and this will mask Lean conditions caused by intake and/or crankcase air leaks.

P0102 means for some reason there is not likely a signal from the MAF. Verify if the MAF connector is properly plugged in, sometimes the female terminals in the connector are spread and loose on the MAF pins, sometimes there are broken wires inside the wiring harness between the MAF and the wiring box near the throttle body and sometimes the MAF just is bad with no output signal.

WARNING - DO NOT buy a cheap ebay MAF, there are many Asian counterfeits on the market that do not work properly. See of there is an MAF reading in Grams/Sec. Most E46 have an idle MAF reading of between 3.5-4

Note, there may or may not be Lean Codes showing up. Lean Codes usually trigger at around 10% Fuel Trim values or higher. Keep in mind that sometimes these engines can have a Lean condition that does not or only intermittently triggers Lean Codes. This is why monitoring the Fuel Trims in real time is important. Ideal Fuel Trim values are typically in the 0% to +2.5/+3.0% range.

Read this thread - http://forum.e46fanatics.com/showthread.php?t=1057387

Make ABSOLUTELY sure the O2 sensor wiring has not been mixed up, read these links:

http://forum.e46fanatics.com/showpos...0&postcount=27

http://forum.e46fanatics.com/showpos...0&postcount=26

Read my "BMW 20 Questions" comments in this thread - http://forum.e46fanatics.com/showthread.php?t=1059972

Check for or be aware of cracked valve covers and bad valve cover gaskets:

http://forum.e46fanatics.com/showthread.php?t=1021219

http://forum.e46fanatics.com/showthr...e=2&highlight=

http://forum.e46fanatics.com/showthread.php?t=1053359

This information ASSUMES that spark plugs have been checked/replaced. If they have not been inspected, you also need to check for oil filled spark plug wells due to a leaking/cracked valve cover gasket.

http://forum.e46fanatics.com/showpos...2&postcount=11

Search YouTube for Scotty Smoke Test. Do what Scotty does or build a tester from related video. Remove the oil fill cap and make sure the crankcase fills up with smoke, put the oil fill cap back on and check for leaks around the valve cover, oil fill cap, dipstick tube and CCV hoses. Cracked valve covers are pretty common on the E46 as it ages.

Note that the Scotty Smoke Test method is not so good for smaller air/vacuum leaks or fully filling the engine crankcase, for this you really need a smoke machine that can provide a solid and continuous low pressure smoke stream. So plan on building a smoke tester of you thing you will use if more than once or may have smaller and harder to find leaks.
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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, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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

Lower hose temp switch O-ring - BMW #13621743299
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Old 08-07-2015, 10:43 AM   #3
rsyed07
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My Ride: E92 335is, E46 330i
Did your mechanic pull any codes. Is your check engine light/service engine soon light on? It has to throw some codes. If you don't have a code reader with you right now you can at least go to your local autozone or advanced auto and pull the codes. It might not pull everything but it will pull most. Just by going with what you said I think you have one or a combination of the following: bad fuel pump, dirty fuel filter, intake cam sensor going bad, a coil going bad. But cannot confirm until you post codes.

And invest in one of the OBDII readers jfoj mentioned. It's an essential with our aged cars.
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Old 08-07-2015, 11:03 AM   #4
sportwagenmann
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Join Date: May 2013
Location: Florida
Posts: 5
My Ride: 2002 325it
Wow! Thanks so much to the both of you. It looks like I have a lot of reading to do. I will check the threads that are posted, and also stop by the local Autozone to see what they are showing as far as codes go. Does it make any difference as to if it's Autozone, or will any of the big box car parts places do just as well? We have most of them within a 5-10 mile radius. Thanks again.
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Old 08-07-2015, 12:34 PM   #5
330ci04vert
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My Ride: 2004 330ci Vert
doesn't matter which car place reads the codes for you, just so that you actually get the codes read! in my home town before I got the software and an obd2 cable myself, as well as a peake scanner (and everytime I read one of jfoj's posts I try to remind myself to buy a bt odb2 scanner lol) but the autozone in my home town had a cheap scanner that wouldn't connect to my car for some reason, but o'reilly had a little better scanner that connected and read my codes back then, so you may very well have to try differen't car parts stores for one that will read your cars codes, but as soon as one does then you're good to go
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Old 08-07-2015, 12:49 PM   #6
sportwagenmann
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Join Date: May 2013
Location: Florida
Posts: 5
My Ride: 2002 325it
Again, thanks for the valuable info. I seem to recollect that one of the auto parts stores I went to recently said they weren't getting any codes reading. I will stop by a couple, there are roughly three right in a line on the same road within 2 miles of each other.
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Old 08-07-2015, 02:04 PM   #7
jfoj
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Ignition needs to be on, engine can be running.

Sometimes the OBDII tools from parts stores have bent pins because these things can be abused, check the pins before you plug it into your car.
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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, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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

Lower hose temp switch O-ring - BMW #13621743299
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Old 08-07-2015, 02:25 PM   #8
BMWCaptain
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Posts: 3,427
My Ride: 03 330iT SportWagon
Check your DISA. check to make sure your flap is working and the pin is still installed.


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Old 08-13-2015, 02:08 AM   #9
joker330ci
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Hey I'm having the exact same problem quick fix I found is to unplug your maf sensor and tape up the connector till you can sort something out or figure the problem but other then that I'm clueless as to what it is I have a red light where your handbrake light is when I take the handbrake off and the abs light both on but the abs is probley to do with my traction control not working but I have a 330ci and its doing the exact same thing as yours any ideas anyone I don't want to go buy a code reader or get codes read because I haven't got time I replaced the rocker cover gasket a while ago can't remember if the problem was prior to it being changed, is there a possibility I cracked the cover putting it back on? And how do I find this pin and flap on the disa to see if it all still works

Last edited by joker330ci; 08-13-2015 at 02:08 AM.
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Old 08-13-2015, 04:20 AM   #10
jfoj
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My Ride: 330CiC, M5, X5, E93
Quote:
Originally Posted by joker330ci View Post
Hey I'm having the exact same problem. Quick fix I found is to unplug your maf sensor and tape up the connector till you can sort something out or figure the problem. Other then that, I'm clueless as to what it is.

I have a red light where your handbrake light is, when I take the handbrake off and the abs light both on but the abs is probley to do with my traction control not working. I have a 330ci and its doing the exact same thing as yours, any ideas anyone.

I don't want to go buy a code reader or get codes read because I haven't got time. I replaced the rocker cover gasket a while ago can't remember if the problem was prior to it being changed, is there a possibility I cracked the cover putting it back on? And how do I find this pin and flap on the disa to see if it all still works


A little bit of sentence structure goes a long way. I did not rewrite what you posted, just used some punctuation and spacing to make it easier to follow.

So, you do not want to buy a code reader or get the codes read because you do not have time? I am a pretty busy person and I seem to be able to respond to a lot of threads. How can I/we help you if you do not want to help yourself? $30 or less an you can have your own OBDII App that will pay for itself the first time you use it. Somehow I guess the Scottish/Wales hold on the wallet worked its way half way around the world? Without any data or clues, everything is a pure guess.

Also suggest you start your own thread once you have some form of data, until then, read what I wrote in post #2 above and you pick your next plan of action.
__________________
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, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

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

Lower hose temp switch O-ring - BMW #13621743299

Last edited by jfoj; 08-13-2015 at 04:22 AM.
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Old 08-13-2015, 06:11 AM   #11
Jaundiced Outlook
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e e cummings, E46 owner...
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