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Old 07-21-2016, 01:01 PM   #1
Tini_Lynn
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Join Date: Jul 2016
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My Ride: '03 325i
Moody starting problem

Looking for a little help.
Ok so this is my first post so if I leave out some details or something I'm sorry. So my car ('03 325i) has been being a moody b*tch lately. Out of nowhere when I would go to start it. It would start up and the immediately the RPMs would drop all the way back down and it would die. Sometimes I can rev it up right after I start it and it would stay going. Sometimes though it won't even let me rev it up. When I try I will hear a noise, I don't really know how to explain it, but it's like the car recognizes that I'm trying to rev it but the powers not going through all the way. And sometimes my car starts freaking perfectly without revving it up or anything. So when I can't get it to start at all I will pull out the code reader and hook it up cause my check light will be in. Again it likes to be moody. Sometimes it will pull up no codes. When it does that I will try to start it and bam it magically freaking starts up perfectly again and stays going. Other times I will get a 'MAF or VAF A Ckt low input' code. I will be honest, I'm a girl no one taught me anything about cars except how to change my oil and a tire. I'm slowly learning, mostly because I'm a stubborn woman that wants to fix everything herself. So with that said... I basically understand that MAF means mass air flow and I have no idea what the rest of that means lol. Also as soon as I plug in the code reader and get that message, I start up the car and bam it's freaking perfect again. WTF!? So right now I'm carrying my code reader around in my car to make sure I don't get stuck anywhere.

Summery
Car sometimes starts perfectly
Sometimes dies immediately after start-up
Sometimes Reving solves issue
Sometimes not
Sometimes no codes
Sometimes MAF code
Always starts after reading codes
Bi-polar car + dumb girl can't solve issue

Any advice on what might fix this?
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Old 07-21-2016, 01:11 PM   #2
lingon300k
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You're smarter than the majority of people who own these cars; you know what a code reader is and want to fix things yourself.

JFOJ, who seems to be the expert on this sort of thing, will chime it at some point with much better info.

It sounds to me like it's either the mass airflow sensor, or an alternator/battery issue. A vacuum leak is always a possibility as well.

If it is the mass airflow sensor, you could consider this part--it's OEM and it's $130 less than the Siemens/VDO: https://www.fcpeuro.com/products/bmw...56-13621432358
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Old 07-21-2016, 02:39 PM   #3
Tini_Lynn
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Thanks I will have to try to look into that a little better. Since it seems so randomly picky I was really wasn't sure what was going on. I don't really think there is anything wrong with my batter or alternator though. It starts perfectly everytime just dies immediately, and I'm not having any other problems with it. Once I get it started everything is perfect I won't have any lights on or funny noises. It's just getting it to stay going upon starting. Since it starts everytime after I plug in the code reader I was a bit concerned of some kind of electrical issue though. I will look into the MAF sensor though. Thank you.
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Old 07-21-2016, 02:48 PM   #4
lingon300k
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Quote:
Originally Posted by Tini_Lynn View Post
Thanks I will have to try to look into that a little better. Since it seems so randomly picky I was really wasn't sure what was going on. I don't really think there is anything wrong with my batter or alternator though. It starts perfectly everytime just dies immediately, and I'm not having any other problems with it. Once I get it started everything is perfect I won't have any lights on or funny noises. It's just getting it to stay going upon starting. Since it starts everytime after I plug in the code reader I was a bit concerned of some kind of electrical issue though. I will look into the MAF sensor though. Thank you.
The code points to the MAF.

Does the car ever stall after it's been running for awhile? Or is is always immediate?

These cars, apparently, are quite sensitive to voltage irregularities, and can show multiple problems due to alternator/battery issues.

How many miles?
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Old 07-21-2016, 03:05 PM   #5
tks
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Sounds like that dirty son of a MAF again!!

Che k out jfoj's thread, and see if you can pull the actual code, usually a Pxxxx (4 numbers)
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Old 07-21-2016, 03:11 PM   #6
Tini_Lynn
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Oh yeah now that I think of it. Sometimes it does. If I'm zooming along on the highway and hit traffic. I don't think it has actually stalled... Maybe once or twice I'm not sure. Usually though once I hit traffic and have to stop really quick, the RPMs will drop supper fast and it will kinda struggle a second and my oil light will pop on for a brief second like it died but then it stabilizes. Does it sometimes in stop and go traffic only on the freeway though for some reason. I just assumed I'm a bad driver in Houston traffic with a five speed.
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Old 07-21-2016, 03:14 PM   #7
Tini_Lynn
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Yeah the code is P0102 and it's got about 180k miles so it's getting up there. I fully intent to run her till she just can't no more though she's my baby. My first owned dream car.
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Old 07-21-2016, 06:12 PM   #8
lingon300k
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Sounds like MAF. And fuel pump. Much lower on the list would be alternator/battery.

I would replace both the MAF and fuel pump, if the fuel pump is original. Siemens/VDO for the fuel pump and the Bremi unit I linked to for the MAF. The Bremi is my recommendation and what I'm planning to install when mine goes, and the Siemens/VDO pump is overwhelming considered to be the only good option by almost everyone on this forum. FCP has a lifetime warranty on all parts, and they really do mean it. Full refund within 90 days, replacements after that.
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Old 07-21-2016, 07:04 PM   #9
jfoj
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So P0102 is a code for MAF circuit Low Voltage.

The issue is you need to narrow down is the problem with the "circuit" (i.e. wiring) or the actual sensor.

These cars are known to have wiring breaks inside the wiring harness back near the throttle body. Also the female terminals can spread and become loose on the the male pins in the MAF.

Not sure what OBDII tool you have. If is supports Live/Realtime data, you can bring up the MAF reading while the engine is idling, note the MAF reading in grams/second, then wiggle the MAF connector and wiring and see if the MAF signal drops out. This may help isolate if the problem is with the "circuit" or wiring rather than the sensor.

Post any Freeze Frame info you may get. Also post warm idle Fuel Trims values as well.

A fair note on the Bremi replacement MAF. I worked with someone recently that felt the Bremi was a good replacement option at a lower price point. The had been chasing problems for a while. Bought a Bremi MAF and thought the problems were resolved, a few days later, same problems. Was somehow able to return the Bremi MAF and purchased a quality Siemens/VDO MAF, problems solved.

Given the age of the car, I would consider a fuel pump replacement as mentioned. Assuming the car is not an SULEV it is fairly cheap and easy to install. Around $135 and easier than changing the oil or a tire IMHO.
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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 07-22-2016, 12:12 AM   #10
Tini_Lynn
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Thanks I think the code reader can do the real time thing I will try to test it out tomorrow if I get time. Next question real quick though... What is SULEV?
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Old 07-22-2016, 12:29 AM   #11
lingon300k
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Quote:
Originally Posted by Tini_Lynn View Post
Thanks I think the code reader can do the real time thing I will try to test it out tomorrow if I get time. Next question real quick though... What is SULEV?
Super Ultra-Low Emission Vehicle. The fuel pump is sealed in the gas tank. Apparently it's a fortune to replace.

I think they were only sold in California, Massachusetts, New York and Vermont. Your car probably isn't SULEV in Texas.

Last edited by lingon300k; 07-22-2016 at 12:32 AM.
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Old 07-22-2016, 04:01 AM   #12
jfoj
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Quote:
Originally Posted by lingon300k View Post
Super Ultra-Low Emission Vehicle. The fuel pump is sealed in the gas tank. Apparently it's a fortune to replace.

I think they were only sold in California, Massachusetts, New York and Vermont. Your car probably isn't SULEV in Texas.
SULEV vehicle may have originally been sold in limited areas, but after 10+ years you never know where these cars will end up. Typically 2003-2004 and sometimes 2005 models could be SULEV. The fuel pump is sealed in a $7000+ stainless steel gas tank. The pump is warranted for 15 years/150k miles, but you only get it replaced if it fails, not from a PM standpoint. The entire fuel tank needs to be replaced in a SULEV vehicle.

The VIN can be run via www.realoem.com or look under the car and see if the gas tank seems to be black plastic or metal. If metal, the car is a SULEV.
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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 07-22-2016, 04:02 AM   #13
jfoj
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Quote:
Originally Posted by Tini_Lynn View Post
Thanks I think the code reader can do the real time thing I will try to test it out tomorrow if I get time. Next question real quick though... What is SULEV?
What is the make and model of the OBDII tool?

Is the OBDII tool an smart phone/tablet based App?
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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 07-22-2016, 04:39 AM   #14
finewayne
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OBDII Tool is available on Iphone, Android, and Windows

This video might helps:




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Old 07-30-2016, 11:39 PM   #15
Tini_Lynn
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Thanks guys! Sorry I haven't replied apparently my notification emails have been going to me spam folder. I've been busy and haven't checked if my scanner can do real time yet. I should be able to check it tomorrow. Hopefully. However, while I'm here... I'll probably make another post about how this but... So with all this happening my car has been sitting for about a week now and this morning I went to go check it out and someone apparently hit it. So yay me it's already acting up and now I have physical damage. They didn't leave any info so I'm stuck fixing this on my own. I'll be needing a new hood, front passenger fender panel and headlight. Do you guys have any advice on a good place to order these parts? Can your order them already painted to match? And how hard are they to replace? I already mentioned I'm stubborn and cheap lol I'll take a grinder with a cutting disk to get the old side panel off if I have to but I obviously will have to put the new one on too.
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Old 07-31-2016, 03:44 PM   #16
Tini_Lynn
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Ok I got the code reader hooked up while its idling. It does to real time but it's showing 0.00 for my MAF values. Still looking to find out which is the fuel trims one... Lol
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Old 07-31-2016, 04:04 PM   #17
Tini_Lynn
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Ok my FTRM 1&2 both ST and LT are showing 0.0 my FTRM 3&4 ST and LT are showing -100.6
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Old 07-31-2016, 04:09 PM   #18
Tini_Lynn
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Also I can completely disconnect my MAF connection and my car still runs...
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Old 07-31-2016, 04:13 PM   #19
Tini_Lynn
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Ok... I erased the codes and restarted the car now I'm getting different FTRM values
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Old 07-31-2016, 04:24 PM   #20
jfoj
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What OBDII tool are you using???

MAF's rarely fail and show 0 g/s. More likely a wiring/connection problem.

LTFT will probalby be 0% if the MAF is not working, but STFT may be showing some value.

Fuel Trims should not show as 100%, if is does, I question the OBDII tool.
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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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