Hi All, been a while since I've been on the site but as they say "true friends know no time limits" my 53 plate MK 3 with 102,000 mls on the clock has just failed it MOT on exhaust emissions, specifically the Lamba readings. I put it back into my garage to fix and they have called me and said they don't know what wrong. They say they have fitted new sensors and that everything is working but still the reading is too high. They suggest I book it i with Toyota which I have done but does anyone have any ideas. I'm off to France in it on 28th and the MOT runs out on27th so it's a bit of a problem that I could do without. Any advice would be welcomed
How far out? Any scans you can post.
Cat up to temp before test
Zorst or induction air leak?
Are you able to read the fuel trims?
Any codes to read
Stock answer: clean MAF.
When was the car last serviced?
Air filter has a massive effect on fueling. You'd be surprised how many garages "service" your car and leave the air filter.
Pass co and hc but fail lambda I'd think might be an air leak - flexies are a common cuplrit.
Wish I knew how to post pics, this would be a lot easier.
Min temp 60 deg Fast Idle Failed
Passed CO and HC
failed lambda 0.97-1.03 temp 1.08
Second fast idle
Passed CO and HC
Failed lambda
Min temp 60deg 0.97-1.03
Temp gauge 1.07
Natural Idle pass
All double Dutch to me
Methinks the lads be correct. Leak somewhere after the MAF. So that's anywhere from directly after the MAF where it connects to the throttle body, to an exhaust leak before the post-cat sensor.
By the by the next person to come in here saying the post-cat o2 sensor doesn't affect fueling is getting the pants of shame for 2 years
Would the fact that both sensors read the same indicate anything
Quote from: Midlifecrisisman on July 17, 2018, 16:18
Would the fact that both sensors read the same indicate anything
Yes. It indicates that your cat is thoroughly knackered.
Assuming you mean o2 sensors in manifold vs o2 sensor post-cat.
But that would most likely lead to high CO levels as well
If the post-cat is following the manifold o2s, the cat is doing nothing
Mine failed on Lambda readings, my HC and CO were well within limits - I found a slight exhaust leak on my TTE system between the backbox and the tip - I have a feeling that this then meant that a small amount of air was getting into the exhaust stream just before the tester's emissions sniffer probe.
Do you have an OBD2 reader as you can then check to see the O2 sensors in the manifold are correctly cycling between rich and lean.
As said, given the above, most likely just a small leak. It's barely out of spec
Quote from: Midlifecrisisman on July 17, 2018, 13:42
Wish I knew how to post pics
@Midlifecrisisman (https://www.mr2roc.org/forum/index.php?action=profile;u=22437) , use the "attachments and other options" if you're using the forum website (if your photos are too large and aren't accepted, you can take a screenshot of the photo, and attach the screenshot instead :) )
Does it have a duel exit exhaust?
I've had high lambda readings doing mots if the other pipe isn't bunged up with a cloth..
Just a thought..
Yahoo, Sorted,
After Toyota had the car 3 1/2 days and charged me £300, problem solved. Turns out that the TTE exhaust is probably an after market affair and where it clamps to the silencer, it was simply a butt joint which was sucking in air. They welded two sleeves onto the twin tail pipes and fitted new gaskets and jobs a good'n
Of to France for a fortnight all legal Go. Thanks for all the advice Guys
I'm the last person here that wants to rain on your parade. (Or pi55 in your chips) as we say in lecky.
But, the TTE is Toyota's own exhaust.(and highly desirable) If the the Toyota dealership is not aware of that, that is quite worrying. They were never welded. Just 2 gaskets and 2 clamps £10 parts, tops.
I'm pleased for you and truly wish you a great time in France.
But, on your return. You might want to question their actions.
All your ammunition is right here on this site.
Quote from: Ardent on July 26, 2018, 22:23
I'm the last person here that wants to rain on your parade. (Or pi55 in your chips) as we say in lecky.
But, the TTE is Toyota's own exhaust.(and highly desirable) If the the Toyota dealership is not aware of that, that is quite worrying. They were never welded. Just 2 gaskets and 2 clamps £10 parts, tops.
I'm pleased for you and truly wish you a great time in France.
But, on your return. You might want to question their actions.
All your ammunition is right here on this site.
Is he possibly trying to say that his zorst isnt an actual TTE but another after market zorst perhaps with TTE tips?
Maybe.
Quote from: shnazzle on July 17, 2018, 15:53
By the by the next person to come in here saying the post-cat o2 sensor doesn't affect fueling is getting the pants of shame for 2 years
LOL - I've heard that so many times, but figured I'd rather get everything working than fudge it when my sensors needed replacing... glad I did.
I take it the JDM cars have different ECU coding then, so they don't look to use that data for fueling... as apparently "JDM don't have the post-cat sensor" or is that another PantsOfShame-worthy regurgitation of misinformation?
I still can't believe the difference it made to my fuel economy (all three sensors).... I thought I was getting 25-27mpg because I was just driving it THAT hard... still driving it the same (if not slightly harder in the dry weather)... and now I'm consistently getting 33-35mpg!
Quote from: Midlifecrisisman on July 26, 2018, 21:47
Yahoo, Sorted,
After Toyota had the car 3 1/2 days and charged me £300, problem solved. Turns out that the TTE exhaust is probably an after market affair and where it clamps to the silencer, it was simply a butt joint which was sucking in air. They welded two sleeves onto the twin tail pipes and fitted new gaskets and jobs a good'n
Of to France for a fortnight all legal Go. Thanks for all the advice Guys
The OEM TTE exhaust is made by Remus, worth around £3-400 and are highly sought after, the original TTE clamps aren't available anymore but there are alternatives from different cars - I think the gasket is from an Audi 80 and the clamp from a Citroen Berlingo - I had to seal up one of mine for the MOT, cost around £10 in parts and about 15 minutes to fit. Its a conical gasket much like the main cat to backbox join and can leak over time.
Interesting to see what your exhaust looks like, very concerned the dealer didn't know what an OEM part looked like and how to fix it.
The JDM ECU definitely doesn't support a post cat o2 sensor. It's deffo a different piece of software in there compared to the UK market cars.
Quote from: jonbill on July 27, 2018, 15:13
The JDM ECU definitely doesn't support a post cat o2 sensor. It's deffo a different piece of software in there compared to the UK market cars.
Now we just need to stop people with UK spec cars from saving £40 and trying to run theirs without the post-cat sensor! Not sure which of the three sensors made the difference (two were failing: one manifold, one cat), but that's >20% improvement in fuel economy!
Quote from: BahnStormer on August 3, 2018, 08:31
Quote from: jonbill on July 27, 2018, 15:13
The JDM ECU definitely doesn't support a post cat o2 sensor. It's deffo a different piece of software in there compared to the UK market cars.
Now we just need to stop people with UK spec cars from saving £40 and trying to run theirs without the post-cat sensor! Not sure which of the three sensors made the difference (two were failing: one manifold, one cat), but that's >20% improvement in fuel economy!
Amen brother
Just to add to that...my post-cat o2 readings are whack (either o2 or exhaust leaks) and my car is now dumping between 8 to 13% more fuel in than it did the day before.