[V8] Code 2341 - disconnected OXS, still rough, plus exhaust hissing

[Ed Kellock]

 One is the bolt that secures the cruise control bracket to the block.

Ed

> -----Original Message-----
> From: v8-bounces at audifans.com 
> [mailto:v8-bounces at audifans.com] On Behalf Of urq
> Sent: Tuesday, February 03, 2009 9:28 PM
> To: 'Audi V8Q Mailing list'
> Subject: Re: [V8] Code 2341 - disconnected OXS, still 
> rough,plus exhaust hissing
> 
> 
> If so, why didn't things pick up when the OXS is 
> disconnected?  The OXS or FPR may indeed be (or have been) 
> bad, but if so, the exhaust hissing indicates that the extra 
> rich exhaust caused damage to the cats.  
> 
> I must say that I don't think it is wise to recommend 
> connecting the ground for the 4-wire OXS to anything other 
> than the engine block.  If things get better at all after 
> grounding to the car body you must have had a really bad OXS. 
>  By connecting the ground of the OXS to the body of the car 
> you are guaranteeing that the ECU will get a signal which is 
> affected by battery/alternator load.  People seem to think 
> that there's such a bad connection between the crossover pipe 
> and the engine block that a good connection to the shiny 
> ground on the body of the car *has* got to be better ... but 
> since the OXS current is very small the resistance is less of 
> an issue.  
> 
> If you look at the wiring diagram for the PT/ABH and focus on 
> how the ground wires are arranged between the ECU and the 
> engine, the grounding was designed specifically to provide a 
> reference for the sending units which is not affected by the 
> current induced voltage changes on the circuits for the 
> output devices (injectors, ignition coils, solenoids).  By 
> connecting the OXS ground as you have the reference for the 
> OXS signal is having to pass through the high current ground 
> braid that goes from the body of the car to the engine block.  
> 
> There are at least two bolts on the back of the engine which 
> were intended for providing a proper reference.  It is 
> perfectly acceptable to recommend someone use a 4-wire OXS, 
> but for anyone who chooses to do so, look for these points on 
> the engine and figure out a way to connect the OXS ground 
> wire to one of these points.  
> 
> Steve B
> San Jose, CA (USA)
> 
> -----Original Message-----
> 
> 
> I'm gonna go with you just got a bad O2 Sensor, and when you 
> replace it 
> You should use a 4wire unit, Run the extra ground that you 
> have on the 
> 4wire one up to the drivers strut tower and ground it with 
> the rad fan. 
> 
> _______________________________________________
> Audifans V8 mailing list
> Send posts to: mailto:V8 at audifans.com
> Manage your list connection: 
> http://www.audifans.com/mailman/listinfo/v8
> 
> You can help keep the audifans site running by shopping at 
> http://audifans.com/shop/
> 
> No virus found in this incoming message.
> Checked by AVG - www.avg.com 
> Version: 8.0.233 / Virus Database: 270.10.17/1932 - Release 
> Date: 02/03/09 07:57:00
>