04 precat failure? Jury is out....

Anonymous · March 15, 2006, 10:41

I have a couple of questions people.

My 2 was in for it's 2 year/20,000 mile service two days ago. Car is exactly two years old and has done a smidge under 14,000 miles. Completely standard, no mods at all.

The only thing I asked them to have a look at / listen to on top of the normal service was my exhaust. Over the last six weeks I had noticed the "note" of the exhaust had changed, particularly at low revs/under load/pull away. Not a blowing sound, just a throatier/farty/hollow sound.

I specifically asked them to pop the O2 sensors and have a peek at the precats. Apparently it was easier for them to just do an emissions test s:roll: :roll: s:roll: (yeah right.......) which it failed. They said the 3rd 02 sensor was not working. I just got a shrug of the shoulders when I pointed out I had not had a sniff of a CEL light.

They have booked it in for 2 days next week for "investigation". When I commented that was a long time for investigating, they sheepishly said they had seen this before where (in their words) "the cat has collapsed and is smothering the 3rd sensor".

So, my questions are......

Can broken pre-cat material make it as far as the 3rd 02 sensor, I thought the sensor was after the main cat which would catch most of the crap?

I didn't think the 3rd O2 sensor could fail and not throw a CEL?

Thanks for your help guys, I just get that feeling I am not being told 100% of the facts. s:? :? s:?

Chris · March 15, 2006, 11:50

I seem to recall the sensors get covered in oil and stop working - have you noticed increased oil use?

Or maybe i'm getting the wobbly crank/oil use problem and the pre cat problem mixed up... s:roll: :roll: s:roll: s:oops: :oops: s:oops:

Anonymous · March 15, 2006, 12:34

Quote from: "Chris"have you noticed increased oil use?

Possibly. It's all in the timing!

In the 6 months I have owned the car it has not used a drop of oil. I check it religiously every week. Literally the weekend before the service the level had dropped to half way down the dipstick. This was in a weeks worth of driving (about 300 miles for me). So I can't say conclusively at this stage if it will continue to eat more oil. Time will tell!

Anonymous · March 15, 2006, 16:31

IIRC, the 3rd O2 sensor is just a check to see if the correct emissions are being released, and that's all. The JDM cars don't even have one.

The main cat itself should not collapse (or at least, I've never heard of it), so I'm willing to bet that the pre-cats have gone and blocked the main cat, and that's what they're trying to tell you.

MAKE THEM CHANGE THE PRECAT MANIFOLD AND THE CAT STRAIGHT AWAY.

They will do it under warranty, as they did for me. If you're very lucky, you may have caught it in time, although I have to admit that's unlikely at this point.
Don't drive the car if you help it, you'll just make the problem worse.

Sounds like to me you're the 2nd case of pre-cat failure on a post-facelift car, after me (although I caught mine just in time). s:(

s:(

Anonymous · March 15, 2006, 19:35

Quote from: "Ekona"Sounds like to me you're the 2nd case of pre-cat failure on a post-facelift car, after me (although I caught mine just in time). s:( s:(

My gut feeling is you are correct......I got the distinct impression they had looked into it further than they were letting on. They were insistent at this stage they would need it for 2 days....hmmm. s:roll: :roll: s:roll:

It could be just paranoia in my case, and it may just be a faulty O2 sensor. But that wouldn't explain the distinct change in exhaust note, which is NOT my imagination!! s:o

s:o

Anyway, will find out for sure next week. It's a good first test for them, being my first visit to this dealer (ironically my first visit to ANY Toyota dealer since buying the 2!!).

FWIW, they stopped talking to me like an idiot once I mentioned MR2ROC, and they visibly paled when I mentioned a certain Stuart.....he appears to be somewhat infamous in there! (Abbey Redhill) s:wink: :wink: s:wink:

Anonymous · March 15, 2006, 21:37

If the 3rd O2 breaks, then you will definately get a CEL. The car will run as normal apart from that.

If their diagnosis is correct, then two days just to replace the main cat and an O2 sensor? More like 2 hours, and that's being generous. If it were me, I'd stand over them and demand that they remove the top O2 sensors before you (accept any liability for any damage it may cause, it's a bit past that now if my suspicions are correct and you can get a new manifold easily enough i.e. I've got one you can have) and have a look down the holes. If there is no pre-cat left, then you will need a new manifold, new cat, and probably new engine if it's already damaged.

Don't take any rubbish from them: You're well under warranty, and stick by your guns and they will do what you ask. I did, and managed to save my engine in time. Good luck!

Anonymous · March 15, 2006, 22:15

Thanks for your thoughts Ekona. I will be making sure the car is put right, don't worry about that! Quite like a good confrontation every so often, gets the heart pumping... s:)

s:)

I made a conscious decision over the last six months not to gut my precats whilst the car was still under warranty. I can't say I wasn't well informed (by this OC) and have posted on a couple of occasions on threads about my decision.

Now's the time to stand by my decision (right or wrong) and make sure Toyota do right by me and the warranty we all pay for in the price of a new car. s:x :x s:x

I'm only kicking myself that I haven't got an O2 sensor tool yet, so I could have a quick peek inside the precats and know the score before handing the car over. Will see if I can pick one up locally or find one online with fast delivery (going to be tight though).

Anonymous · March 15, 2006, 22:18

See, I went the other way to you and decided that warranty alone wouldn't stop me from gutting them. Whilst I'd love to sit here and grin like a smug git, I can't because it's a horrible thing to have happen to a fellow '2 owner. s:(

s:(

Keep checking the oil usage, and keep notes. That'll help you when/if you need to push for a new engine.

Anonymous · March 16, 2006, 08:13

Quote from: "Ekona"See, I went the other way to you and decided that warranty alone wouldn't stop me from gutting them. Whilst I'd love to sit here and grin like a smug git, I can't

s:lol: :lol: s:lol: s:lol: :lol: s:lol: I've got a sneaky feeling there will be one or two members out there just itching to say "I told you so"! More than a couple of members tried to persuade me to gut the precats regardless of warranty........ At the moment I am still happy with my decision to rely on my warranty......that may well change if it is the precats and the (ahem) "negotiations" begin with Toyota.

I will update this post in a few days so the flaming s:flame: :flame: s:flame: can commence.

BTW, if it is the precats, does that mean I will have the newest reg. with lowest miles failure? Gee wow, golly gosh, one to tell the grandkids......... s:roll: :roll: s:roll:

Anonymous · March 23, 2006, 14:47

Just thought I would do a final post to tie up this thread.

Local T garage had the car yesterday. They removed the manifold and say they were surprised to find pre-cats were still completely intact. They still fitted a new manifold (as it wouldn't pass an emissions test with the old one in) and it then passed the test. s:)

s:)

Having had a good poke around this morning it does indeed look like a shiny new manifold.

The "odd' exhaust note has now gone, and to be fair, the car feels a little smoother in certain situations (not that I had noticed a change before!).

The best they could come with as to what was wrong with the old precats was "some form of contamination, perhaps sir?", so not really a conclusive answer. I couldn't push for a new cat aswell as they adamantly say the precats were 100% intact, and it now passes the gas test, so no grounds. s:? :? s:?

Suffice to say I will be watching the oil level just as carefully as before (hasn't used a drop since being serviced 500 miles ago) and chucking it back at them if there are any more probs s:wink: :wink: s:wink:

At least everything has been apart now so should make future gutting a relatively painless job....fingers crossed s:roll: :roll: s:roll:

mrsmr2 · March 23, 2006, 17:12

Very relieved for you.

Any chance you can see the old manifold and precats just to make sure?

Would make it easier to make a claim in future just in case they were not 100% and some bits had made it into the engine after all. Still, judging by the results of the recent pre-cat gutting meetings, the pre-cats seem to hold up on the newer cars.

Anonymous · March 23, 2006, 17:35

Quote from: "weaselchops"can commence.

BTW, if it is the precats, does that mean I will have the newest reg. with lowest miles failure? Gee wow, golly gosh, one to tell the grandkids......... s:roll: :roll: s:roll:

No I think MRMike had only done 6000 miles when his went

GSB · March 23, 2006, 18:00

Quote from: "weaselchops"The best they could come with as to what was wrong with the old precats was "some form of contamination, perhaps sir?",

Thats what happened to mine... s:cry: :cry: s:cry:

When I checked my '54 plate car with barely 500 miles on the clock, I found to my surprise they'd been contaminated with an enormous screwdriver...
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Chris_h · March 23, 2006, 18:37

Just wondering folks, why does pre cat failure = oil usage?

I would have thought they would only provoke oil usage if they had already broken AND damaged the engine?? - in which case the engine would already be pretty knackered...

I wish I'd never read anything about precats - makes me kinda nervous...

Anonymous · March 23, 2006, 21:43

Grant is, of course, correct. If you're a fanatic with respect to maintenance, you'll want to perform a precat inspection as soon as possible. The procedure requires removal of the manifold, and then removal of the precat material. Put the material into a small box and inspect it at your leisure.

Because Toyota has refused to publicly acknowledge this design fault, we really don't know exactly what causes precat failure. Could be the rings, the cylinder boring, the polystyrene wrapping of the precat material, the ceramic matrix itself, failure to warm the motor fully before use, or a harmonic resonance at upper RPMs. All have been suggested and there are various reasons to believe any of these theories. Possible it's a combination of the above. Maybe it's something else.

Since we don't the cause, we don't know how to evaluate the various rumors that Toyota has addressed the issue from a design standpoint. Maybe they fixed the problem. Or maybe they just did something that they believe fixes the problem but actually doesn't.

The prudent procedure is to perform a full precat inspection.

Anonymous · March 23, 2006, 22:19

chops, if its not 2 late i have an o2 sensor socket u can have free( give a £5 to the club) but i cant post it till monday aft, as im 12 hour shifts fri/sat.
let me know if u want it m8.

loadswine · March 23, 2006, 22:36

If you inspect the O2 sensors regularly, be careful with their threads. One of mine was seized solid when I did the gutting and had to be retapped.
Ill see if this link works for a few pics of my precats just before I introduced them to my large screwdriver!
http://photobucket.com/albums/f313/2000silver2/precats/?sc=1&multi=4&addtype=local&media=image&test=test
I think someone mentioned about the scooping effect on the precat surface. You should see something like that here. I'm guessing that's one of the reasons my 2 uses a drop of oil, as abrasive material may have been ingested into the bores at some stage. How much and extent of damage? Don't know, may have caught it in time, we shall see. Been done for a year, but that's only 2 or 3K for my car.

Anonymous · March 24, 2006, 09:59

Quote from: "GSB"When I checked my '54 plate car with barely 500 miles on the clock, I found to my surprise they'd been contaminated with an enormous screwdriver...

s:lol: :lol: s:lol:

Quoteyou'll want to perform a precat inspection as soon as possible. The procedure requires removal of the manifold, and then removal of the precat material. Put the material into a small box and inspect it at your leisure.

s:lol: :lol: s:lol: Who says sarcasm is the lowest form of wit?

Quotechops, if its not 2 late i have an o2 sensor socket u can have free( give a £5 to the club) but i cant post it till monday aft, as I'm 12 hour shifts fri/sat.
let me know if u want it m8.

Massive thanks for the offer. s:bowdown: :bowdown: s:bowdown: You are a top man. Now the car has been back to toyota I can pick one up at my (relative) leisure in readiness for the imminent gutting ahead. You hang on to it, maybe another more needy case will come along. s:wink: :wink: s:wink: