S4 / RS4 (B5 Platform) Discussion Discussion forum for the B5 Audi S4 & RS4 produced from 1998-2002

2000S4 issues - Part 2

Thread Tools
 
Search this Thread
 
Old 02-12-2009, 02:06 PM
  #1  
New Member
Thread Starter
 
951guy's Avatar
 
Join Date: Feb 2009
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Default 2000S4 issues - Part 2

Problem solved, I thought I would share the result, especailly with my new buddy Reefer_Bob.
EGT sensors...fine (suggested replacement cost $500)
O2 sensors....fine (suggested replacement cost $500 for all 4)
Coil packs...fine, spark plugs fine (but replaced anyway).
Real problem - MAF Sensor.
As I mentioned in the original post , I don't like the concept of throwing $ at a problem just hoping to fix it. Based on recommendations I would have burned over $1k with no results.
Thanks to those that did offer real help.
Old 02-12-2009, 02:18 PM
  #2  
AudiWorld Super User
 
reefer_bob's Avatar
 
Join Date: Oct 2002
Posts: 14,321
Likes: 0
Received 0 Likes on 0 Posts
Default

f'in a cotton! f'in a...
Old 02-12-2009, 02:24 PM
  #3  
Member
 
sj6sp's Avatar
 
Join Date: Feb 2002
Posts: 2,908
Likes: 0
Received 0 Likes on 0 Posts
Default Glad you got it sorted out. You might x-post your fix to your original problem to help out others

that have similar symptoms.

How did you figure out it was the MAF?
BTW, the bosch MAF in 2000 S4s are prone to failure.
Old 02-12-2009, 02:34 PM
  #4  
New Member
Thread Starter
 
951guy's Avatar
 
Join Date: Feb 2009
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Default "So pretty please with sugar on top, change your f'ing egts"

so now I should change the cotton?
Old 02-12-2009, 02:36 PM
  #5  
AudiWorld Super User
 
reefer_bob's Avatar
 
Join Date: Oct 2002
Posts: 14,321
Likes: 0
Received 0 Likes on 0 Posts
Default

If you can dodge a wrench, you can dodge an egt!
Old 02-12-2009, 02:37 PM
  #6  
Junior Member
 
dzzeiks's Avatar
 
Join Date: Aug 2008
Posts: 760
Likes: 0
Received 0 Likes on 0 Posts
Default

nice, how did you figured it out?
Old 02-12-2009, 03:33 PM
  #7  
New Member
Thread Starter
 
951guy's Avatar
 
Join Date: Feb 2009
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Default Dodge? no, its an Audi

now I'm goofing on you...
Old 02-12-2009, 03:41 PM
  #8  
New Member
Thread Starter
 
951guy's Avatar
 
Join Date: Feb 2009
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Default Some logic and some investigation

The failed sensor answer couldn't really apply since the trouble occured even when dead cold - the EGT and the O2 both need a short warm up period - you can unplug the O2 sensors and the ECU will run on a default value.
It turns out you can do the same thing with the MAF, the ECU uses RPM and throttle position to approximate a air flow value. As soon as I unplugged the MAF it ran much better.
A little more research shows up a weakness in the 2000 MAF sensors, should be replaced with the latqer Hitahci unit.
Old 02-12-2009, 04:14 PM
  #9  
Member
 
sj6sp's Avatar
 
Join Date: Feb 2002
Posts: 2,908
Likes: 0
Received 0 Likes on 0 Posts
Default You can replace with a Hitachi but it's not plug n play.

Need software for a Hitachi car (01/02) and recode the instrument cluster.

When I popped a pressure hose my car wouldn't run for crap even to limp home. Unplugged the MAF and started right up and ran fine.

Nice troubleshooting! I hate throwing money at a problem when a little tinkering can find the culprit.
Old 02-12-2009, 06:23 PM
  #10  
Junior Member
 
DocSlowMiniPerson's Avatar
 
Join Date: Jan 2008
Posts: 1,679
Likes: 0
Received 0 Likes on 0 Posts
Default

Congrats! Totally overlooked that as a potential cause. :-(


Quick Reply: 2000S4 issues - Part 2



All times are GMT -8. The time now is 01:09 PM.