E46 2004 325i Misfire Under Heavy Acceleration [SOLVED] - Page 2 - E46Fanatics E46 BMW Social Directory E46 FAQ 3-Series Discussion Forums BMW Photo Gallery BMW 3-Series Technical Information E46 Fanatics - The Ultimate BMW Resource BMW Vendors General E46 Forum The Tire Rack's Tire Wheel Forum Forced Induction Forum The Off-Topic The E46 BMW Showroom For Sale, For Trade or Wanting to Buy

Welcome to the E46Fanatics forums. E46Fanatics is the premiere website for BMW 3 series owners around the world with interactive forums, a geographical enthusiast directory, photo galleries, and technical information for BMW enthusiasts.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features. By joining our free community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join our community today!

If you have any problems with the registration process or your account login, please contact contact us.

Go Back   E46Fanatics > E46 BMW > General E46 Forum

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!

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 03-15-2017, 10:17 PM   #21
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
The problem is the MAF rate in g/s at idle is WAY low.

It makes sense, about 30% too low. MAF reading at warm idle 700 RPM in P/N should be around 3.8 g/s, yours is showing 2.78 g/s.

SO, is this due to a soft failed or counterfeit MAF or are the MAF readings this far off due to the VE of the engine being cut due to the restricted exhaust??

I guess you could play a bit, get a MAF reading, then pull the #1 Pre-cat O2 sensor and see if the MAF value increases by around 10-15% assuming the value reduced equally across both Banks.
__________________
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
jfoj is offline   Reply With Quote
Old 03-16-2017, 09:58 AM   #22
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
I guess you could play a bit, get a MAF reading, then pull the #1 Pre-cat O2 sensor and see if the MAF value increases by around 10-15% assuming the value reduced equally across both Banks.
I'll tinker with it more tonight after work. Thinking about this based on my limited knowledge, doesn't it almost have to be bad sensors? Either MAF or O2's or both? If the engine was really running THIS lean wouldn't it be running pretty poorly? When my E39 was running lean due to a broken CCV line it idled terribly.
ryanr1299 is offline   Reply With Quote
Old 03-16-2017, 10:25 AM   #23
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
The O2 sensors are not likely the problem, you first need to understand why the MAF reading is so low. Either a soft failing MAF, Asian counterfeit or the exhaust is highly restricted killing the VE of the engine.

I would pull the Bank #1 Pre-cat O2 sensor and see if the MAF reading increases noticeably. If it does, then you could pull the Bank #2 Pre-cat O2 sensor and see if the MAF value gets closer to 3.4-3.8 g/s.

Otherwise the MAF may need to be replaced for starters, but this car seems to have a number of problems. Maybe the converters are restricted due to an Asian counterfeit MAF being run for too long?
__________________
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
jfoj is offline   Reply With Quote
Old 03-16-2017, 11:12 AM   #24
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
this car seems to have a number of problems.
You can say that again! It's been a good learning exercise, though. No way to know about the MAF, it is a VDO MAF but to your point could be counterfeit and if not who knows how old it is. Thank you for your continued help, I shall do as you suggested and report back.
ryanr1299 is offline   Reply With Quote
Old 03-16-2017, 11:17 AM   #25
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
I just do not want you to drop big $$$ on a MAF when the problem may actually be clogged/restricted exhaust.

Easy enough to pull a Pre-cat O2 sensor and see if the MAF value changes, if not, then make sure the female MAF terminals inside the MAF connector are tightly grabbing the male terminals in the MAF. I often squeeze them closed just a bit to make sure there is a good contact. If no improvement, then the a replacement or test MAF is the next step.

Anyone can cast plastic and print labels these days, so you never know if the Siemens/VDO MAF is really a Siemens/VDO MAF!!!
__________________
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
jfoj is offline   Reply With Quote
Old 03-16-2017, 11:34 AM   #26
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
I just do not want you to drop big $$$ on a MAF when the problem may actually be clogged/restricted exhaust.
For sure! Especially when a MAF costs more than the car did. I'll also check the connections again. When you mentioned this I looked back at previous warm idle log and it was right around 3.7 to 4 g/s and the MAF has been in and out many times since then.

Sent from my Nexus 5X using Tapatalk
ryanr1299 is offline   Reply With Quote
Old 03-16-2017, 01:53 PM   #27
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
Maybe you have created an air leak that you did not have before? Maybe there is a loose connection?

I found that the clamp on my MAF was not even tight after someone else was under the hood for something!! You always need to check behind both yourself and others for the obvious things.

Good luck.
__________________
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
jfoj is offline   Reply With Quote
Old 03-17-2017, 04:35 PM   #28
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Checked the MAF connection before starting, and even pressed the female connections inward a bit to ensure good contact. Idled the car until it was warm and as the engine warmed up the MAF reading dropped back to around 2.8g/s and held pretty steady. Shut it down and pulled bank 1 pre-cat and started it back up, once the RPM's settled after a few seconds the MAF reading was still around 2.8g/s.

So to be thorough, I then pulled the bank 2 pre cat and started it again (bank 1 also still out at this point -- my neighbors love me!), and MAF reading jumps only very slightly to 3.0g/s and pretty much holds steady there.

Soooo...bad MAF?
ryanr1299 is offline   Reply With Quote
Old 03-17-2017, 05:38 PM   #29
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
I would be leaning on a MAF as a source of the low g/s reading.

Since this is a 2004, it should have a 5 wire MAF which has the IAT integrated into the MAF so it will be stupid expensive compared to the 3 wire MAF's.

I would show around, www.oembimmerparts.com seems to have good pricing on a reliable product (non Asian counterfeit) but you can also use this tool to find the best pricing www.bmwpnpc.com
__________________
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
jfoj is offline   Reply With Quote
Old 03-19-2017, 08:34 PM   #30
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
New manifolds are in. Didn't have the right bolts to connect them to the main pipes so holy crap it's loud right now. But it feels like a whole different car!

On to sorting out the lean condition!!

Sent from my Nexus 5X using Tapatalk
ryanr1299 is offline   Reply With Quote
Old 03-19-2017, 08:50 PM   #31
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
Pictures of the outlet side of the old manifolds if you have a borescope or can peek in the outlet side of the manifold. I would expect the outlet side of the catalyst to be melted.
__________________
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; 03-19-2017 at 08:54 PM.
jfoj is offline   Reply With Quote
Old 03-19-2017, 09:14 PM   #32
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
I have a cheapo USB snake camera, I'll try to get pictures... Might be able to get a decent shot with a regular camera on the bank 2 cat, it's pretty close to the outlet flange.
ryanr1299 is offline   Reply With Quote
Old 03-20-2017, 12:59 PM   #33
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
Pictures of the outlet side of the old manifolds if you have a borescope or can peek in the outlet side of the manifold. I would expect the outlet side of the catalyst to be melted.
Inlet seems to be the problem. First three images are the inlet side of the cat, last two are the outlet side.









ryanr1299 is offline   Reply With Quote
Old 03-20-2017, 01:41 PM   #34
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
Interesting.

We have seen a lot of these cars with problems more on the outlet side than the inlet side.

Helpful when we are able to get some sort of feedback, maybe at some point we will be able to fully understand what is causing the premature converter and/or exhaust valve problems.
__________________
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
jfoj is offline   Reply With Quote
Old 03-21-2017, 05:09 PM   #35
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
You always need to check behind both yourself and others for the obvious things.

Good luck.
MAF is on order but decided to heed this advice and check everything again. Evidently the clogged exhaust was adding more noise than I realized. Now that it's quieter i noticed the following: a high pitched whistle under high rpms while driving, definitely an air sucking sound. So if stand outside of the car with the hood open and engine running and blip the throttle, there is a very noticeable whoosh sound coming from around near the throttle body. I can only hear it for a second right when I hit the throttle and before the engine spools up and drowns out the sound.

I triple checked the intake boots were installed correctly but once the engine is cooled down again I will be going back in.

Sent from my Nexus 5X using Tapatalk
ryanr1299 is offline   Reply With Quote
Old 03-21-2017, 05:29 PM   #36
jfoj
OEM ///Member
 
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 23,188
My Ride: 330CiC, M5, X5, E93
These engines have a vacuum leak sound from the idle air bypass.

You cannot worry about the sounds too much.

Smoke Testing and monitoring Fuel Trim values are the best way to verify the engine fuel management system is working properly.
__________________
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; 03-21-2017 at 05:29 PM.
jfoj is offline   Reply With Quote
Old 03-21-2017, 06:40 PM   #37
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i
Quote:
Originally Posted by jfoj View Post
These engines have a vacuum leak sound from the idle air bypass.

You cannot worry about the sounds too much.

Smoke Testing and monitoring Fuel Trim values are the best way to verify the engine fuel management system is working properly.
Roger that.

I did some poking around before I saw your reply and found the vac cap missing from the CCV (on the extra port not used on this engine). So one small item corrected at least. I'll wait for the MAF before I do anything else. Car runs great right now. If I'm still lean after MAF I'll break out the smoke!

Sent from my Nexus 5X using Tapatalk
ryanr1299 is offline   Reply With Quote
Old 03-27-2017, 07:33 AM   #38
ryanr1299
Registered User
 
Join Date: Feb 2017
Location: DFW
Posts: 149
My Ride: 2004 325i, 2001 530i


The MAF did the trick! I think my fuel trims are still running a bit high so I'll circle back to that in the future (more pressing matters to address on the car). But after picking this thing up a month ago with a ton of codes and barely running to today when it's running like a champ and ready for emissions testing!! Great feeling.

Many many thanks jfoj! You're an asset to this forum -- much of your other info outside of this thread helped get me to this point as well.



Sent from my Nexus 5X using Tapatalk

Last edited by ryanr1299; 03-27-2017 at 07:44 AM.
ryanr1299 is offline   Reply With Quote
Reply

Tags
not fuel pump

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Censor is ON





All times are GMT -5. The time now is 04:02 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
(c) 1999 - VerticalScope Inc. All rights reserved.