[Oldfocus]

Okay, this is getting a touch tiring (kind of like Ford's lack of quality commitment...). My O2 sensor gets toasted every time I blast down tha 401 at 180k in 4th (with Ford's "brilliant" gearing who needs 5th? (A slight digression... The transmission is a four speed with overdrive NOT a 5 speed...)).

Mods... Cat2's and a chip to let it idle and enrichen the mixture above 4k revs. Also intake, throttle, and UDP.

My own theory (to be put to the test shortly) is that the sensor gets too hot in its close proximity to the head. I'm adding an SVT header with the Random cat from McNews which whould move the O2 sensors downstream a bit.

Without quoting from today's Toronto Star article could someone in the know enlighten me as to how to correct this situation permantly? O2 sensors aren't cheap, and the effects when they die are dangerous (step on the gas and car dies). I use PetroCan't 91 most of the time and sillycone has never been near my gaskets (unless my significant other has been lying about the naturally pendulous hooters...).

Any help would be appreciated.

[boost til'bust]

you said you have an intake? do you have an aftermarket air filter, such as a k&N, because they are soaked with a silicome based product.

I highly doubt it is the heat that is the problem, they work better when they are hot, and I have had to heat some up with a torch to remove them, and they have not failed.

posible causes: silicone as you mentioned, usually comes from that coating that is on aftermarket filters.

if you bang the sensor at all, the inside element will break very easily, and if there is any stress on the wires to the sensor this can cause problems too.

coolant leak into the cylinder will clog the sensor, or even a really rich mixture can cause the sensor to clog and read slowly, causing a code.

the question is...when you say toasted? what does that mean? is there a code? what is the code, the code will tell you which of these is most likely.

[tdot-zx3]

I have an extra ford focus o2 sensor hanging around the house somewhere.... Wish i knew where it was .. id sell it to ya cheap cheap.

Yes i know this doesnt help.

[ZX5]

take it in and ask them to clean it......they cleaned mine out for me and it worked fined after that......it mite cost you a little bit of ca$h...... so maybe you can try that

ZX5

[Oldfocus]

Boost: NO CEL ever with this thing. Yes, I have an aftermarket intake with a flat panel copy of a K&N (came with Iceman in 2000). Essentially the sensor seems to fail. Its especially noticeable when the engine becomes heat soaked. Engine just bogs below 3.5 grand and often times will just die. (Essentially all the behaviour listed in the FocusSport Focaljet thread on same...).

[darkpuppet]

Hmmm.. I've been in only 1 other person's focus running stage 2 cams...

and his car threw a cel...

then I gotta wonder what's up with your timing and fuel enrichment that is toasting the O2 sensor with that kind of frequency.

You need to hit a dyno with wideband O2 and see if the commanded air/fuel is what the car's really doing... if not, especially if you've richened the mixture in closed loop (over 4k), you may be experiencing a MAF problem... oil coating on filter could foul it, force the car to run the failed tables, and under heat, those tables are useless.

if, after a couple of runs you can confirm the command a/f is the same as what's coming out the tailpipe, you can go back and see what you can do about the O2 sensor...

after all that, I gotta wonder what you're doing blasting down the 401 at 180km/h .. and doing it that frequently... we're all susceptible to the odd moment of immaturity, but if this is your standard practice, you need to cool it down before you kill someone or yourself.

[Oldfocus]

Darkpuppet,

I will in fact be hitting a local dyno as soon as the header is installed. As for doing 180kph (and sometimes more...) probably has something to do with years of driving in Germany, France, Italy, and the UK. Oh, and of course it all started in Quebec. I'm not sure why Ontarians are so anal about speed. (Must be the Cracker Jack box licenses they hand out here... <grin>)

[darkpuppet]

the dyno will give you the best indications of what's going on. Do you have an OBDII scanner/datalogger to use?

I'm not going to debate the speed issue in this thread, but it's a common misconception that driving fast = good driving... regardless how much the autobahn has in common with the 401 (they have fast, crappy roads in germany?)..

[boost til'bust]

Oldfocus,Sep 13 2004, 07:17 PM Wrote:Boost: NO CEL ever with this thing. Yes, I have an aftermarket intake with a flat panel copy of a K&N (came with Iceman in 2000). Essentially the sensor seems to fail. Its especially noticeable when the engine becomes heat soaked. Engine just bogs below 3.5 grand and often times will just die. (Essentially all the behaviour listed in the FocusSport Focaljet thread on same...).

remind me agian why you think its the oxygen sensor?

is there a code????

maybe you have a different problem? there are many things that can cause that same problem. I highly recommend the car is properly diagnosed before you keep replaceing the sensor. it needs to be checked for codes first and if there are no codes, PID data must be monitored.

[Oldfocus]

Dark,

Sorry, no data logger.

Boost,

After reading about O2 sensor's curing this problem over in the Focaljet FocusSport thread I decide to try it on mine. Problem disappears completely. Three or four days later its back. Change sensor and it disappears again. (Interesting trivia... Motorcraft sensors are made in Japan, while Bosch (the Kaiser of Darkness) is made in the US...)

As noted in the afore mentioned thread the problem also disappears if I remove the chip, but then of course I don't have an idle either.