Don Terrill’s Speed-Talk

The moisture was already IN THE SENSOR before you fired the engine. The moisture on the sensor element killed the sensor within seconds of firing that cold engine. Sensor was dead before you got to a two minute run warm temperature.

Again, why are you running more than two sensors anyway??

If you are running headers are your sensors mounted in the top and front area of the collector. If not you are asking for additional trouble.

Gravity controls moisture collection and most deposits, water included will not foul a 02 sensor as quickly if you keep the sensor in the top pointing downward.

cardo0 wrote: ↑Sun Feb 10, 2019 1:27 pm Bosch also tells us the following:

“The sensor must not stay in the exhaust gas stream when it is not heated or when the control unit is switched off.”

Most manufacturer’s of aftermarket wide-band Lambda controllers, pass this point on in their instruction manual in one form or another. It is indeed true that leaving a sensor in the exhaust system without it hooked up to a fully functional controller will kill the sensor. However, doing this for a couple of seconds isn’t a problem. In talking with many of our customers who are the end user’s of aftermarket wide-band controllers, we have often found that many interpret this piece of information to mean that the sensor needs to be fully heated up BEFORE starting the car. In reality nothing could be further from the truth. It isn’t a co-incidence that these customers are the same ones that are killing sensors frequently. After having a brief chat with them and setting them straight their ongoing sensor problems often disappear.

http://www.nzefi.com/bosch-lsu-wide-ban ... lications/

More takeaway from the linked article:

http://www.nzefi.com/bosch-lsu-wide-ban ... lications/

Bosch thoroughly points out that the sensor heating must only start after the engine is running and even then the heater power should be limited to about 15% of its full value until condensed water is sure to be gone. Only then should high-powered rapid-heating of the sensor occur. The following comments come directly from Bosch:

“In the warm-up phase at engine start, the sensor is operated with reduced heater power..……. The heater power must only be increased when the presence of condensed water in the exhaust gas system can be ruled out.”

“The sensor ceramic element is heated up quickly after heater start. Prior to heating up the ceramic element, it must be guaranteed that there is no condensed water present. This could damage the hot ceramic element.”

“Never switch on sensor heating or the control unit before engine start.”

“….. the sensor installation location design must be selected in a way to minimize, or eliminate, condensed water on the exhaust gas side from contacting the sensor. If this is not possible by design measures, the start of the sensor heater must be delayed until demonstrably no more condensation water appears.”

I use an ntk sensor and the manufacturer of the controller (AFR500) says that the for best life to let it warm up fully as indicating by the countdown provided (30s). I've used this to tune cold start with EFI for years it works a treat and have waited the full countdown for dozens and dozens of times. Usually I do not wait unless I'm tuning. The only time I had issues once was rich missfires over an extended period of time that killed a sensor.

I don't know what NGK say regarding warmup it would be interesting to compare the brands if anyone knows

Well the contradiction in information is clear.

I'm willing to give cleaning them a try (although I do not expect much). If rust, what would be a good cleaning method ?

Thanks

Rust on the sensor is not the problem!

Trying to clean an O2 sensor head and its coatings will destroy it quicker than the moisture that's killing yours.

If you don't believe people with actual years of experience then please call tech at BOSCH and they will tell you what your problem is.

I remember back last year how hard it was to get you to understand what the problem was with your EFI stack intake manifold PCV chamber oil problem.

You are a tough one to teach some needed knowledge.

Not saying to offend but I am glad you are not one of my customers! I'd have to fire you.

Have you reached out to 14point7, he is a very good tech resource.

Are the sensors clocked between 10-2 at a minimum? Moisture is not your problem unless you are mounted roughly 4 oclock to 8 oclock. They have to be basically submerged to be ruined by moisture. Millions of cars have a ton of condensation in the exhaust, most do not have problems with o2 sensors. Moisture is to be expected per innovate manual.. Unless your sensor is mounted at 6 oclock Moisture is NOT the problem.. Moisture burns off to quick unless sensor is placed wrong.
Also Lots of other things are considered way worse than a little bit of moisture. oil burning, very rich afr, wrong sensor placement, Oil with extra zinc, leaded fuel, oil burning, antifreeze (not moisture from antifreeze but the chemicals), , Ever see how much condensation and water that is present in exhaust systems? It is alot.

Installed a innovate mtxl in 2008 In a turbocharged application POST turbo. You know that sensor just died finally 6 months ago.. It was mounted at 12 o clock. If moisture killed 02 sensors with heaters in them, there would be an awful lot of bad sensors everyday. There is a few things to look at before saying what is killing your O2's.

Newold1 wrote: ↑Mon Feb 11, 2019 9:44 am Rust on the sensor is not the problem!

Trying to clean an O2 sensor head and its coatings will destroy it quicker than the moisture that's killing yours.

If you don't believe people with actual years of experience then please call tech at BOSCH and they will tell you what your problem is.

I remember back last year how hard it was to get you to understand what the problem was with your EFI stack intake manifold PCV chamber oil problem.

You are a tough one to teach some needed knowledge.

Not saying to offend but I am glad you are not one of my customers! I'd have to fire you.

Where is his moisture coming from? You mean normal everyday condensation in the exhaust system? Moisture will not kill an o2 in a very long long time if the sensor is mounted straight up. Also most people understand why he is running 8 o2 sensors. He may want to tune each individual cylinder.

Newold1 wrote: ↑Mon Feb 11, 2019 9:44 am Rust on the sensor is not the problem!

Trying to clean an O2 sensor head and its coatings will destroy it quicker than the moisture that's killing yours.

If you don't believe people with actual years of experience then please call tech at BOSCH and they will tell you what your problem is.

I remember back last year how hard it was to get you to understand what the problem was with your EFI stack intake manifold PCV chamber oil problem.

You are a tough one to teach some needed knowledge.

Not saying to offend but I am glad you are not one of my customers! I'd have to fire you.

you fire a customer ?

S10LS2 wrote: ↑Mon Feb 11, 2019 3:22 pm

Newold1 wrote: ↑Mon Feb 11, 2019 9:44 am Rust on the sensor is not the problem!

Trying to clean an O2 sensor head and its coatings will destroy it quicker than the moisture that's killing yours.

If you don't believe people with actual years of experience then please call tech at BOSCH and they will tell you what your problem is.

I remember back last year how hard it was to get you to understand what the problem was with your EFI stack intake manifold PCV chamber oil problem.

You are a tough one to teach some needed knowledge.

Not saying to offend but I am glad you are not one of my customers! I'd have to fire you.

Where is his moisture coming from? You mean normal everyday condensation in the exhaust system? Moisture will not kill an o2 in a very long long time if the sensor is mounted straight up. Also most people understand why he is running 8 o2 sensors. He may want to tune each individual cylinder.

correct for individual fueling of each cylinder.

So you are running 8 -O2 sensors? One for each cylinder? I would have to assume they are in bungs on the top of each header tube where it bends into the exhaust port in the head??

I have only seen and done something like this on a dyno, but not in a car. If this is your installation I wish you had described that configuration because when I read your post I took from it that you were talking about the two O2 sensors that are placed in the exhaust at each side of the engine that most EFI ECM's require for ECM tuning.

I don't think moisture is going to be an issue that far up the exhaust if that is how your 8 -O2's are mounted and used.

I can tell you when we tried a similar setup on a dyno and were attempting to tune an IR intake system and we had a heck of a time keeping the exhaust gas temperatures at that point just outside the head port in a range that did not cook the O2's.

We finally and ever since use the UNI-Syn air flow balance tool to adjust the IR throttle plates and linkage as close as needed.

If you use 8-O2's I am not sure they would all calibrate the same and if you get that setup to work for initial or on a wheel dyno. I would then remove the 8-O2's, plug the bungs and switch back to a in collector 2 sensor system for driving the vehicle.

If this is your situation and setup- please be more detailed in your system description in the future and I WON'T BE SO QUICK TO FIRE YOU!!

Yes, over the years there are few customers that you can't work for or with and firing them was and is the best solution! You can't please all customers all the time.

The sensors are not close to the head. They are about half way between the port and collector or close to the collector (as far towards the collector as I could put them physically). I have put them as much upright as possible. Some obviously needed to be more towards the 3 or 9 o'clock position because of space constraints.

The setup worked and has proven it's value, aside from the sensors getting destroyed. The only thing in common between sensors going bust is they do this after a winter of sitting still. Previously I had one or 2 of them fail, but this time they all went out, which is even more remarkable. Going to check electrical connections tomorrow and pull a number of them out to see if something turns up.

If I don't find anything I'll have to return to one sensor in each collector and pull them out every winter.

Did some checking today :
- battery : charged it and then tried again, no avail.
- disassembling a sensor and visual inspection : nothing
- blowing out sensor with compressed air : nothing
- checking resistance between pin 3 and 4 (heater wiring) : no resistance indicating the heater circuitry is in short circuit.

So at least it seems that this is not related to the ceramic element which usually goes bust when moist is involved (gauges show constantly 14.7/1 which seems to indicate the ceramic element is ok, but not working properly due to not being heated).

Something causes the heater to go into short circuit. Everything is properly wired with several inline fuses and each sensor has its own fuse according to instructions. Don't know.
If rust would be the cause: rust is not conductive...unless it's moist.

This makes me wonder what to do next : dry them ? blow them out ?

no resistance indicating the heater circuitry is in short circuit.

This sounds more like an open circuit?
Is the sensor heating element designed to be heated all the time or only long enough to get the sensor up to temp?
Maybe the heater is running all the time, burning the element out?

I think switching occurs at the controller. So when measuring from the plug towards the sensor, it should not show 0 resistance.