Fouled oxegen sensor

[rfoll]

I have an aftermarket afr gauge setup in my car. The 12 volt supply to the system failed while I was on the road, (gauge quit working, reason unknown), and I ended up putting over 50 miles on it with no sensor heat. When I found the voltage issue and hooked it back up, the gauge started reading erratically. Number on the sensor 0 258 007 206, LSU4.2, 12 575 657. I managed to find a replacement for $40, shipped directly from China. Everything else was over $100. I'm back and running again, but I wonder if the fouled item can be cleaned to restore it to usable condition. A bath of oven cleaner comes to mind.

[peejay]

Nah, if you run a Bosch wideband sensor without heat, it wrecks it.

Throw in a new sensor and call it a day.

I'm actually kind of surprised at the price jump recently. I used to treat the 4.2 in my Innovate LC-1 setup as a consumable/disposable because I could easily find them for $35 thanks to some VW class-action lawsuit regarding failures or price gouging or something. The last one I bought was late last year for under $40, retail, with sales tax. Now, I can't find them for under $80 at jobber pricing.

Might be time to finally upgrade to something that uses an NTK sensor. Those things are pretty much bulletproof. They can even handle leaded fuel!

[In-Tech]

As far as I know once they are ruined from non power, they are toast, David???

The reason for my reply...how many holes are in the exhaust end of the o2 sensor, 6 or 12? Can you post pictures of exhaust end as well as connector end?

edit,

peejay, the bosch 17014(6 hole lsu 4.2) the innovate LC-1 uses can be had at oreillys or autozone for 49.95 and if you have a commercial acct they are 46.95

[Tuner]

Connect the fouled sensor to the gauge/controller and power it up so the heater circuit is on and roast it with a propane torch while you watch the gauge. It should eventually come around when the carbon burns off. A propane torch can't heat it any hotter than it gets in an exhaust stream, probably not as hot. The thimble will need to be red or orange/yellow hot (as viewed in a dark room - not sunlight) to burn off the carbon. You should be able to see the gauge respond to the A/F of the torch flame. If a sensor is fouled with silicone it will be slow to change numbers, but if the numbers change rapidly it is probably OK. I have cleaned a lot of them this way. I snag them out of the trash at the ricerboi shop (Home of the Rolin' Coal Turbo Power Tunes for Honda and Subaru) and roast them, they almost always come back to functional.

[user-23911]

If it's getting fouled up in the first place, you've got an engine problem.


NB sensors are similar.
If you run it so rich (cold start) that it chokes with soot, it'll stop working until the soot burns off.
In this case it's got nothing to do with the heater but the tuning.

[In-Tech]

Sorry Joe, I will disagree based on I have seen the WB go dead in a stoich deal when the power was forgotten to the WB. I am speaking of stock vehicles on pump unleaded with NB active and in closed loop. I would like to hear more of peoples experience, good or bad. You bring up a valid point though, how about all those early single wire NB vs heated NB that seemed to recover once the tune was better and closed loop worked correctly.

Carry on

Also, still would like to see the 6 vs 12 hole bosch WB vs part number and connector convo

[rfoll]

It's a 12 hole sensor. It's for the FAST 170634 system. I picked it up at a swap meet in a box full of Autometer gauges for $20. To prove the sensor failure I installed the one from my Innovate LM2.

[rfoll]

If it's getting fouled up in the first place, you've got an engine problem.


NB sensors are similar.
If you run it so rich (cold start) that it chokes with soot, it'll stop working until the soot burns off.
In this case it's got nothing to do with the heater but the tuning.

It got fouled up for lack of 12 volt power as indicated I my original post. The engine is a carbureted 98 Vortec 350. Even when the choke is on, it never runs below stoich. Cruising is around 16.5-17.5.

[user-23911]

It'll be reading wrong.

They're waaaaay over rated.


It's always good to use a NB sensor alongside as a check.

[In-Tech]

It's always good to use a NB sensor alongside as a check.

Yes

I'd like to poll the knowledge base here. All of the research I have done indicates that the bosch 12 hole sensor is a LSU 4.9 and the 6 hole is a LSU4.1 regardless of the connector. There are a few that I have come across that have the exact same connector yet one is 4.2 and another is 4.9 Comments?

p.s. I'll take some pics later and post.

[sr4440]

I run up to 10 O2's on my dyno, some are 6 hole some are 12, all are LSU 4.2's

Joe

[stealth]

Nah, if you run a Bosch wideband sensor without heat, it wrecks it.

Throw in a new sensor and call it a day.

I'm actually kind of surprised at the price jump recently. I used to treat the 4.2 in my Innovate LC-1 setup as a consumable/disposable because I could easily find them for $35 thanks to some VW class-action lawsuit regarding failures or price gouging or something. The last one I bought was late last year for under $40, retail, with sales tax. Now, I can't find them for under $80 at jobber pricing.

Might be time to finally upgrade to something that uses an NTK sensor. Those things are pretty much bulletproof. They can even handle leaded fuel!

Is there a better part number to search by? VW pt number or something?

[In-Tech]

I run up to 10 O2's on my dyno, some are 6 hole some are 12, all are LSU 4.2's

Joe

I will start another post about this. The heater circuit is completely different on the 4.2 and 4.9. I will contact my bosch injector guy in europe and try to get a engineer contact for the o2 so we can get to the bottom of this as far as identifying which is which. From what I have seen, the 4.9 works but not accurately when driven with 4.2 firmware and depending on the circuit will fail the hardware.

Again, I would like to get to the bottom of this. Thank you for your reply.

[adam728]

Connect the fouled sensor to the gauge/controller and power it up so the heater circuit is on and roast it with a propane torch while you watch the gauge. It should eventually come around when the carbon burns off. A propane torch can't heat it any hotter than it gets in an exhaust stream, probably not as hot. The thimble will need to be red or orange/yellow hot (as viewed in a dark room - not sunlight) to burn off the carbon. You should be able to see the gauge respond to the A/F of the torch flame. If a sensor is fouled with silicone it will be slow to change numbers, but if the numbers change rapidly it is probably OK. I have cleaned a lot of them this way. I snag them out of the trash at the ricerboi shop (Home of the Rolin' Coal Turbo Power Tunes for Honda and Subaru) and roast them, they almost always come back to functional.

I've not tried this method, but will say this: Bosch gives EGT limits of 930°C continuous for both the 4.2 and 4.9 sensors, and 1,030°C "for short time". A healthy propane torch will run around 1800-1900 °C.

http://www.bosch-motorsport.com/media/c ... 435pdf.pdf

http://www.bosch-motorsport.com/media/c ... 659pdf.pdf


Of course, if you have a dead/fouled sensor and try the propane trick, about the worst you can do is kill it, which is where you are starting from anyway.

[In-Tech]

Notice the 12 hole in the 4.9 pic vs the 6 hole in the 4.2 pic?

It is my belief the aftermarket has had it wrong for a long lime...I will research