FAO Efi experts: O2 Sensor Tolerance

Stu wrote in news:1137352930 snipped-for-privacy@sp6iad.superfeed.net:

BTW, tried a 30 mile 'italian tune up' today, revving nuts off it, highly illegal speeds etc. Made bugger all difference to sensor outputs :-(

The mother-in-law keeps coming on every few weeks on a Toyota Yaris?

"AstraVanMan" wrote in news:ouxyf.7125$ snipped-for-privacy@newsfe3-win.ntli.net:

Almost as annoying as that, but not quite. At least you can switch it off with the right interface ;-)

Well on the face of it, your live data capture shows exactly the symptoms of a dead or nearly dead Cat. Sensor 2 mimicing the switching of Sensor 1 means that its detecting exactly the same oxygen content downstream of the cat as whats entering it.

There can be no other reason for this to happen other than the cat not functioning.

To double check- have a tailpipe emissions test- bet you it fails, but only just.

Tim..

Assuming you've got the cat hot then it's dead. Although it might be cheaper to buy one from

than the length of time you'll spend arguing with toyota.

Thanks for confirming that, Tim. I've asked Toyota customer relations for an offer of good will and they have referred me to the dealer, so it'll get a 'proper' diagnosis. Whether or not I'll get anywhere with it is another matter!

BTW, sorry for the late response. My news server is playing up so I'm having to post via google for now.

Stu

Thanks for the link, Duncan. Looking at those prices, I would agree that I'm probably wasting my time with Toyota. That's assuming I can get hold of an aftermarket CAT for the 1.5 T-Sport - that website doesn't list it, nor does the online Bosal catalogue (not that I'd buy another component from them).

The Toyota dealer price is nearly =A3500, so they would have to offer a very substancial contribution to make it cheaper than an aftermarket part. I can't imagine that happening, despite the fact that the life of the CAT has been inadequate, to say the least.

The Toyota dealer price is nearly £500, so they would have to offer a very substancial contribution to make it cheaper than an aftermarket part. I can't imagine that happening, despite the fact that the life of the CAT has been inadequate, to say the least.

I've tried some of the cheaper pattern cats and they dont last, the substrate isnt pure enough. I only buy OE or Timax ones now, usually from fuelparts.co.uk

Tim..

"Tim \(remove obvious\)" wrote in news:dql1ld$sq0$ snipped-for-privacy@nwrdmz01.dmz.ncs.ea.ibs-infra.bt.com:

I can't get a price for an aftermarket one, anyway. It seems that nobody manufactures one for the 1.5 T-Sport yet. Looks like it'll have to be an OEM one. If Toyota don't offer anything then it won't be getting changed until it fails the MOT (next due in August).

In the meantime....I have learnt that the secondary O2 sensor should give a steady 0.6v signal to indicate that everything is OK with the CAT. Does the signal circuit sense voltage or resistance? I could easily create 0.6v with a couple of carefully selected resistors. Would that fool the ECU or would it flag a fault due to lack of sensor activity?

Indeed the 2nd sensor should respond with 0.6v or thereabouts which cunningly co-incides with a lambda of 1.00, showing that the cat is functioning.

The ECU only expects 0.6v x minutes after it enters closed loop (where x is enough time for the cat to reach operating temperature.)

I would think the resistor trick would work- no harm in trying.

Tim..

"Tim.." wrote in news:dqnn80$k22$ snipped-for-privacy@nwrdmz02.dmz.ncs.ea.ibs-infra.bt.com:

OK, I'll try that, unless Toyota come up with an offer far better than what I expect (nothing). Car goes in for inspection tommorrow.

I've also thought of another way to avoid getting ripped off - a custom made S/S front pipe incorporating a new CAT. I phoned the local powerflow dealer and he reckons they can make one, or cut out the old CAT and fit a replacement in, for about =A3180! No doubt it will be a bit dearer after I insist on a quality CAT with a S/S monolith and long guarantee, but I'm sure it would still be well short of the Toyota price, plus I would get it fitted.

Cheers

--=20 Stuart Sharp

"Stu" wrote in news:1137689409.992288.182530 @g49g2000cwa.googlegroups.com:

Got nowhere with Toyota, the service rep at the local dealer spouted a lot of crap about how their machine was better and could get more information from the ECU etc. So they plugged it in and read the code, which, of course, was exactly the same code as I had read myself. Then they phoned up and informed me that further diagnostics were required and that it would cost £55. I had a short and frustrating conversation with the service rep, trying to explain that I'd already been out with the car and diagnosed it myself and I wasn't going to pay £55 for someone else to do the same. Unfortunately, she obviously had no technical knowledge whatsoever, yet she refused to conceive that I might possibly know what I was talking about. Her attitude was that they were the dealer, they knew best, I knew nothing. After her ignorance became too frustrating to bear (about 30 sec), I informed her that I was coming to collect the car and hung up.

In any case, I was never going to get Toyota to offer enough cash to give me a cheap Cat replacement - the part from them is simply too expensive to start with. So I have decided on the option of having a new front pipe made that will accomodate a quality universal CAT by Timax or similar.

In the meantime, I have wired two resistors to supply the secondary O2 circuit with a steady 0.6V. The actual value I'm getting off the ECU is

0.57. I hope this will prevent the fault code from registering for now, and maybe it will still pass the MOT in August? The only worry is that the complete absence of switching activity will cause another fault to flag i.e. P0136. I suppose that depends upon how thorough the Toyota system is. Time will tell.

Thanks for the advice throughout.