Let me start out by saying that I love my TTE exhaust. It's the happy mix of a little pop and burble, but without upsetting the neighbours.
However, I can't pass an MOT because my CO is too high. I've had nothing but trouble ever since I went with this exhaust.
I've replaced the gaskets with the Volvo ones from ECP numerous times (I reckon I'm about to replace with the 4th set now). And despite buying the Toyota donut, there's always a slight leak from this too. I've got another brand new one and I'll replace it yet again.
Am I the only one? I really don't want to change my exhaust, but every single year, I have this problem. I've even bought a Carbon Monoxide tester to try and work it all out.
If an MOT tester says you have exhaust leaks then you'll need to fix them. Repeated gasket purchases...???...sounds like you need to think different.
But Googling high CO2 doesn't mention exhaust leaks. It does suggest the MAF or O2 sensors. ?????
What cat are you running? If it's OEM it might be past its best.
High CO tends to be the cat.
Quote from: Carolyn on October 19, 2024, 09:02What cat are you running? If it's OEM it might be past its best.
High CO tends to be the cat.
Cat's fine apparently. I'm pretty sure it's all the leaks causing the problems.
I've had an idea. I have an OEM exhaust here. I might throw that one and see if that gets me through. Then I can start having another think.
@The Other Stu said of his TTE exhaust:
I've had nothing but trouble ever since I went with this exhaust.And then:
I've had an idea. I have an OEM exhaust here. I might throw that one and see if that gets me through. Then I can start having another think.
I'd say that sounds like a plan.
Had TTE on 3 different cars and no issues - I'd say the problem is not the backbox ::)
Quote from: boor on October 23, 2024, 09:13Had TTE on 3 different cars and no issues - I'd say the problem is not the backbox ::)
Oh it is.
I can feel the air coming out of the gaskets on the 2 pipes.
These have been fitted professionally in the past too and eventually, they start leaking.
Quote from: boor on October 23, 2024, 09:13Had TTE on 3 different cars and no issues - I'd say the problem is not the backbox ::)
Unless you had THEIR exhaust on your car, that's just YOUR experience.
They are not all absolutely identical. Especially given how old they are now.
Have you tried and OBD2 scan and checked there aren't obvious O2 sensor problems.
The only time I've failed on emissions are on my old sable: where somebody had blacked out my engine management light to hide the failing O2 sensors and it was running in a safety (VERY rich) mode... it sailed through as soon as that was fixed.
The local mechanic admitted that he runs it at the MOT "manual" rev range, so slightly higher.
In his words: "most Japanese engines are designed to rev higher". He said mine passes, but only scrapes through at standard revs and sails through (WELL within thresholds) at higher revs. My engine is standard, exhaust is Toyosport manifold and TTE, which is a great sounding combination BTW!
OK, so an update to this.
It was indeed the backbox. I replaced the gaskets and collars (I've done this more than once before as above). I also found a small hole on the silencer which is now fixed. And for good measure, I replaced the cat-box gaskets with genuine Toyota ones.
CO was 0.01% (Max 0.20%). Lambda was absolutely on the limit at 1.03. I have a 100cel cat. I'll take that.
I thought I'd replaced both sensors with genuine Denso ones, but having a quick peek, the one on the cat doesn't look genuine, so I'll probably replace that anyway.
I haven't done it.
But as a consumable limited life component, I've considered replacing the top two sensors but shyed away from it in the fear of something going wrong in the getting the old ones out.
Quote from: Ardent on November 14, 2024, 08:08I haven't done it.
But as a consumable limited life component, I've considered replacing the top two sensors but shyed away from it in the fear of something going wrong in the getting the old ones out.
They come out quite easily. I purchased the slotted socket and a breaker bar. Not much effort involved.
I um and ar between takling when stone cold vs hot.
Quote from: Ardent on November 14, 2024, 08:08I haven't done it.
But as a consumable limited life component, I've considered replacing the top two sensors but shyed away from it in the fear of something going wrong in the getting the old ones out.
2ZZ only has 2. One post cat, one pre cat.
I did replace them before when I was failing. It made it worse!
An O2 sensor socket as
@fawtytoo said, is a great investment.