Has Anyone Replaced pre-cat Lambda (Oxygen) Sensor Without Removing Manifold?
#21
AudiWorld Super User
Sorry, I don't get this component reference in general--mixing history
Thanks, interesting what Audi had to do to get those 10-cylinders past US EPA *****!
In that cross-reference are the wire lengths & connectors the same? Curious, not argumentative. I've personally used the "generic" Bosch lambda sensors without any trouble many times. I think the key is weather proof crimp terminals - they have built-in shrink tubing (i.e., the plastic part of the terminal shrinks to become one with its mate) covered with another layer of heat shrink tubing. Just bought a pack of these; they actually solder and shrink simultaneously with a heat gun or a crack torch (I have one in my "road" toolbox for soldering and shrink tubing)! Great reviews but kinda pricey. Have not tried one yet.
I've been crossing Bosch parts for my Alfa since (pre-internet!) 1989... The dealer would give an Alfa/Ferrari P/N and it'd be, say, $250. There was a tiny Bosch authorized shop down the road and he'd cross them over to the "root" Bosch number and it'd be $50.
In that cross-reference are the wire lengths & connectors the same? Curious, not argumentative. I've personally used the "generic" Bosch lambda sensors without any trouble many times. I think the key is weather proof crimp terminals - they have built-in shrink tubing (i.e., the plastic part of the terminal shrinks to become one with its mate) covered with another layer of heat shrink tubing. Just bought a pack of these; they actually solder and shrink simultaneously with a heat gun or a crack torch (I have one in my "road" toolbox for soldering and shrink tubing)! Great reviews but kinda pricey. Have not tried one yet.
I've been crossing Bosch parts for my Alfa since (pre-internet!) 1989... The dealer would give an Alfa/Ferrari P/N and it'd be, say, $250. There was a tiny Bosch authorized shop down the road and he'd cross them over to the "root" Bosch number and it'd be $50.
Yes, you can start down the road of concluding the wideband sensors are essentially generic, and assume your connector or nearby conductors is not actually the issue. Since you will be splicing that is--that is a big assumption BTW and contradicted by W12 experience and fragility of the signal (non power) individual conductors in the overall O2 wire set. Then you can proceed to do the solder in repair (takes two people realistically--BTDT with those specific Tyco connectors), and then either dynamite the wiring harness tape with plastic electrical tape that will fall off in a year, or do it right with the Audi cloth tape that will cost you another tens of dollars.
Net, notice some "***-u-m-ptions" in here and essentially the (non-)economics if you just get the right Bosch sensor by 5 digit #, let alone risk of a connector (or proximity) related failure. There is a time for those Tyco type connectors and I have used them quite successfully on 02 W12 work specifically on the car harness and connector side where you have no other option anyway realistically. Plus, I have used generic 02's back in yesteryear before full plug compatible ones were offered by Bosch. (The old ones were also either simple two wire, or 3 wire heated, and way before the internal electric feedback check systems that often drive the errors/codes now). But in my practical judgment and experience, this is not the scenario really, unless and until following a sensor replace you still have a conductor related O2 error and then conclude it is on the car side of the final connector that comes with the sensor. That is the W12 specific issue for example, and documented in a W12 specific TSB. But here it should be much simpler--plug and play replace a simple O2 at the connector and move on. Use the Bosch one OES at +/- $80-100, or Audi one at 2 1/2x that.
Last edited by MP4.2+6.0; 04-16-2015 at 08:24 AM.
#22
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Thanks, interesting what Audi had to do to get those 10-cylinders past US EPA *****!
In that cross-reference are the wire lengths & connectors the same? Curious, not argumentative. I've personally used the "generic" Bosch lambda sensors without any trouble many times. I think the key is weather proof crimp terminals - they have built-in shrink tubing (i.e., the plastic part of the terminal shrinks to become one with its mate) covered with another layer of heat shrink tubing....
In that cross-reference are the wire lengths & connectors the same? Curious, not argumentative. I've personally used the "generic" Bosch lambda sensors without any trouble many times. I think the key is weather proof crimp terminals - they have built-in shrink tubing (i.e., the plastic part of the terminal shrinks to become one with its mate) covered with another layer of heat shrink tubing....
I know exactly what these connectors are. I posted on them for the W12 repair, when you need to do the car side of the wiring harness and connector for O2 sensors. For a straight sensor replace, this is kind of yesteryear mid 80s stuff to me (for me, the 1985 Audi 5000S). For modern Bosch, if you just get the correct five digit part number, you then have the correct sensor, correct wire length and correct connector color for $80 to 100, instead of $200+ via dealer.
Yes, you can start down the road of concluding the wideband sensors are essentially generic, and assume your connector or nearby conductors is not actually the issue. Since you will be splicing that is--that is a big assumption BTW and contradicted by W12 experience and fragility of the signal (non power) individual conductors in the overall O2 wire set. Then you can proceed to do the solder in repair (takes two people realistically--BTDT with those specific Tyco connectors), and then either dynamite the wiring harness tape with plastic electrical tape that will fall off in a year, or do it right with the Audi cloth tape that will cost you another tens of dollars.
Net, notice some "***-u-m-ptions" in here and essentially the (non-)economics if you just get the right Bosch sensor by 5 digit #, let alone risk of a connector (or proximity) related failure...
...Use the Bosch one OES at +/- $80-100, or Audi one at 2 1/2x that.
Yes, you can start down the road of concluding the wideband sensors are essentially generic, and assume your connector or nearby conductors is not actually the issue. Since you will be splicing that is--that is a big assumption BTW and contradicted by W12 experience and fragility of the signal (non power) individual conductors in the overall O2 wire set. Then you can proceed to do the solder in repair (takes two people realistically--BTDT with those specific Tyco connectors), and then either dynamite the wiring harness tape with plastic electrical tape that will fall off in a year, or do it right with the Audi cloth tape that will cost you another tens of dollars.
Net, notice some "***-u-m-ptions" in here and essentially the (non-)economics if you just get the right Bosch sensor by 5 digit #, let alone risk of a connector (or proximity) related failure...
...Use the Bosch one OES at +/- $80-100, or Audi one at 2 1/2x that.
Audi cloth tape... must buy immediately. Probably won't ever need it. The story of my (garage) life.
"***-u-m-ptions". Yes, I see you attended university!
#24
AudiWorld Super User
B4 S1 means the forward sensors (S1) before the main converters. Bank 4 is the rear of the motor on the right side when you look under the hood--U.S. or Continental Europe driver's side. I'll leave you to figure out which sensor in turn is in the diagram for that rear part of the motor--on an S8 I think the down pipes do some up and down bends like headers so the diagram is confusing. PaulW (more frequent on QuattroWorld than here) and one other poster or two) have dealt with the O2's on an S8. W12 ones turn out to be a lot easier to reach apparently.
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therealfleen (07-28-2022)
#27
MP, are you sure? I "heard" that actually there are two sensors on the W12 that are impossible to swap without dropping engine. The two post cat, most forward ones. B1S2 and B2S2, right?
These two - in red:
I have this recurring nightmare of that happening.... Again....
These two - in red:
I have this recurring nightmare of that happening.... Again....
Last edited by carl viking; 05-28-2015 at 01:49 PM.
#28
AudiWorld Super User
MP, are you sure? I "heard" that actually there are two sensors on the W12 that are impossible to swap without dropping engine. The two post cat, most forward ones. B1S2 and B2S2, right?
These two - in red:
I have this recurring nightmare of that happening.... Again....
These two - in red:
I have this recurring nightmare of that happening.... Again....
Fortunately, pre cat ones are the ones that usually fail (if they do) rather than post cat. The post cat ones don't have the heating element either so are simpler in design.
Last edited by MP4.2+6.0; 05-28-2015 at 07:50 PM.
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