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mot fail today on emissions, anybody on here able to give me any suggestions for possible causes etc
The car is turbod, trd panel filter and put wynns clean burn in the fuel but still no joy.
Sports cat? They need to get pretty hot to work properly.
That was our thought so after the 1st failed test I took it on the motorway for a spin but still failed.
O2 reading is high, maybe a leak on the manifold
Ideally find a "more helpful" mot tester who maybe able to over look the problem s;) ;) s;)
Quote from: "rbuckingham"O2 reading is high, maybe a leak on the manifold
It also is making a rasping noise, very much like the heat shield rattle, but theres no heatshields s could it be manifold gasket ?
Quote from: "s12vea"Ideally find a "more helpful" mot tester who maybe able to over look the problem s;) ;) s;)
ha he was a good bloke to be fair, gave me 3 separate attempts at it, the 3rd one after a blast down the m42
Also was pointed out to me that id only done around 1000 miles since last mot, maybe needs some help like cataclean to aid cat efficiency. Any one tried this?
I have some readings from o2 sensors too,what should they be operating at as mine fluctuate wildly.
I've got a 200 Cel sports cat and it caused no problems at my last MOT.
Do a few more miles than you though.
I've had no end of trouble with exhaust manifold and turbo gaskets sucking in air and causing fueling issues. Mine had a tiny leak between the turbo and manifold which over time caused the long term fuel trims to adjust incorrectly. Disconnecting the battery resets the fuel trims until they have been relearnt. The only way to fix it permantly is the fix the exhaust leak then reset the fuel trims.
Fuel trims if anyone can decipher them for me, car was at 3000 rpm
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Well it needs sorting one way or another s:evil: :evil: s:evil: ive just tightened the manifold to engine, but as ive no mot I cant get out and test it.
Been doing some amateur sleuthing on this and it looks quite odd. First fast idle suggests a lean mixture (lambda >1), but the second suggest it is rich (high CO)!
You say you had 3 tests, we're the results all consistent with the above in terms of how it failed?
Quote from: "lamcote"Been doing some amateur sleuthing on this and it looks quite odd. First fast idle suggests a lean mixture (lambda >1), but the second suggest it is rich (high CO)!
You say you had 3 tests, we're the results all consistent with the above in terms of how it failed?
Yep all the same, the tester thought it was odd too.
It's the long term fuel trims you need to look at.
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Quote from: "Davegtst"It's the long term fuel trims you need to look at.
There you go. They are idling at 1200 then rev to 2500 rpm.
Quote from: "wotugonado"Quote from: "rbuckingham"O2 reading is high, maybe a leak on the manifold
It also is making a rasping noise, very much like the heat shield rattle, but theres no heatshields s could it be manifold gasket ?
Quote from: "s12vea"Ideally find a "more helpful" mot tester who maybe able to over look the problem s;) ;) s;)
ha he was a good bloke to be fair, gave me 3 separate attempts at it, the 3rd one after a blast down the m42
Also was pointed out to me that id only done around 1000 miles since last mot, maybe needs some help like cataclean to aid cat efficiency. Any one tried this?
I have some readings from o2 sensors too,what should they be operating at as mine fluctuate wildly.
I would say it's leaking then, most likely at the turbo, that where my leak was.
One point I have realised in my research is that fuel trims and emissions tests are affected by very different things even though at first glance I didn't realise it:
Fuel trims are influenced only by the car's O2 sensors which are before the cat, there are no CO sensors or HC sensors for the engine to react to and the exhaust gasses haven't been through the cat.
The emissions test is looking at all these things, and after cat treatment, so I wonder how relevant fuel trims are to helping find emissions problems detected in the mot?
The odd thing for me is the fact that it is both lean and rich in consecutive tests. A leak after the O2 sensors and or cat would certainly give a lean reading for the mot test without affecting fuel trims but wouldn't explain the failure for high CO which is a rich issue (I assume).
Thanks for that lamcote.
ive a feeling its an accumulation of things. So im going to do an oil change, run some cataclean through, work my way along the intake checking for leaks.Im going to heat wrap the cat to help get it warmer quicker And change the turbo manifold gasket as its all 2nd hand I cant say if its any good or not. I will also check the 3 amigos and the donut rings as I remember me and my mechanic having fun doing those up. Also after some researching on dual exit exhausts when the probe is put in the one exit block the other up with a damp cloth,
as according to another forum it contributed towards giving a false reading.
All that within the next 10 days .........
Can anybody give me an idea if those fuel trim readings are normal ?
I'm not sure there is an answer to that. The fuel trims are simply adjustments made to whatever Base map the engine is running, based on the readings taken from the O2 sensors. I assume your engine management runs in closed loop using the O2 sensors to initiate the fuel trims but I believe this can be switched off by whoever mapped the engine. There are lots of YouTube videos which explain all this but as I say fuel trims may not help. I have certainly seen comments about people getting false lean results from testers using the equipment wrongly and getting air trapped in the exhaust pipe next to the probe so air might be getting into your exhaust system via the second outlet, this may explain how you are getting the both lean and rich fails, which otherwise seems unusual.
I will continue with my web searching and report back if anything looks helpful.
Edit, having said that there is no answer, it seems that fuel trims at less than 10% are pretty normal and suggest the car is not trying to massively compensate for something. Levels of 25% seem to be a typical maximum.
What management system are you using and have you had it mapped on a rolling road?
This is quite a good read which supports what has already been said.
m http://www.obd-codes.com/faq/fuel-trims.php (http://www.obd-codes.com/faq/fuel-trims.php) m
Cheers guys for the help, good link mrzwei thanks.
Its a tte turbo so it has a chip that you cant alter.
Having thought about it a bit more there's more logic to it than I realised, I told you I am an amateur.....
The first run shows the mixture is too lean (lambda 1.2) and the CO is a pass. In the second test the mixture has got richer (lambda has decreased) and this has caused the CO to increase and fail (too rich). That would actually seem entirely logical. This presumably means that at any given point the engine is running rich relative to the exhaust measurements. That may be supported by the fact that the long term fuel trims all seem to be negative ie taking fuel away to make the mixture more lean.
That suggests that the exhaust has too much air relative to the mixture so the leak theory looks plausible.
Hope my ramblings are not too confusing...
No keep em coming s:D :D s:D i was already confused.
Think I may have an o2 sensor operating slightly out of maximum range too, not much so i dont know if it woud cause an issue.
I suppose having clean and properly functioning MAF and O2 sensors is essential to pass any MOT.
What makes you think the O2 sensor is out of range?
I think operating range should 0.2 to 0.8 volts mine is sometimes closer to 0 and maximum 0.96
dont know if this is enough to be an issue though.
MR2.com says:
Testing O2 sensors on the workbench.
Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age.
Interestingly in the same article it also says if the car thinks the O2 sensor is faulty it will not switch to closed loop operation and will therefore run rich in open loop on the Base map, but wouldn't you get an error code if an O2 sensor was not working properly?
Interesting. Yeah if it was a complete duffer it would give a code. But reading up it maybe just sluggish and may not throw a code.
So im gonna swap them round and see if the readings follow the 02 sensor. Cheers for all the info, appreciate it s:D :D s:D
Right ive swapped the 02 sensors round and now im just as confused. Im trying to learn as i go so if my logic is wrong please say, the long term fuel trims have followed the sensors which i thought was good, indicating a potential dodgy sensor buttttttttttttt then the voltage reading showed the one thats operating strangely mainly holding around 0.74v and not fluctuating (they should fluctuate between high and low volts correct ?)much isnt the one giving the high negative fuel trim.
So could it be the one thats not functioning as it should is giving a false leaner reading meaning that the car is running rich at around -11% ?
I think this is going to be very tricky if there is any suspicion that the O2 sensor(s) is/are not working properly because you will never know what to trust.
Please bear in mind that it is not that the O2 sensors job to fluctuate from high to low voltage. The only reason they fluctuate is because the ECU makes the mixture fluctuate from rich to lean and the O2 sensors then reflect that. If an O2 sensor gives a constant reading that probably means that the sensor is accurately reading a constant air fuel ratio which shouldn't be happening. If that constant ratio is lean, that could be because of a leak, as has been mentioned above. This is why it is essential to know if the sensors are working properly.
Well I found a very good webpage on the denso website all about correct operation of there 02 sensors and they state, that if a sensor reads below 0.1 and above 0.9 then the sensor is faulty even if it doesnt trigger an eml. It shows the wave pattern of how it should operate in normal conditions, when its lean and when its rich.
mine mimics the rich reading quite closely average above 0.45 and spends more time in the top section with not much fluctuation towards the lower end. So ive ordered a new denso sensor for a bargain price of £53.00 delivered from amazon because sparkplugs .co didnt have any in stock s:D :D s:D
We shall see if that helps.........
To be continued s:D :D s:D
Hope it helps, good luck
Hope so, thanks for all your input so far.
Fingers crossed
Yeah cheers. Im still going to follow your advice Nath snd swap the original cat back over, belt and braces type of thing to get it through the mot.
It would be a good idea mate. At least you can eliminate it and it's to the end of the world to swap them over. Especially if it's been off already not all that long ago
Well spent the afternoon stripping it all down to see why ive been having emission problems.
And have to say I found quite a few additional problems on top of the 02 sensor. Theres a split in the internal wall of the cat flexis (see other thread) s:? :? s:? Cant for the life of me understand how that would of happened.
Jubilee clip had punctured the pipe attached to the turbo actuator, and the support bracket holding the exhaust was well on the wonk, so potentially making the main cat pipe to precat joint misaligned s:( :( s:(
2 separate mechanics have worked on the car over the years and not noticed any of these problems, annoyed doesnt cover it.
That's p1ss poor mate.
At least doing yourself you know can get everything how it should be.
Yeah but as an amateur should I really be finding problems that 2 qualified mechanics missed? All I can say is what a great forum this is, had a problem with it running a little rough a while back and actuator pipe was mentioned then.so it seem most problems are diagnosed better on here than by mechanics being hands on with the car s:? :? s:?
Sadly or rather fortunately that's generally the case. There's a lot of knowledge about these cars around here
Aghhhhh ive spent all day on it and am no further along. Its100% the pre cat to turbo join as I sprayed it with washing up liquid and watched the flippin bubbles froth out s:evil: :evil: s:evil: How can it not have a gasket s:? :? s:?
Any suggestion for something I can use as times running out for my retest.
You can get metal gasket paper that you can just cut and make a gasket
Quote from: "rbuckingham"You can get metal gasket paper that you can just cut and make a gasket
Really! Where from and how thick is it ?
Is this it?
m http://www.ebay.co.uk/itm/SHEET-METAL-E ... 0521429127 (http://www.ebay.co.uk/itm/SHEET-METAL-EXHAUST-GASKET-MATERIAL-GASKET-CARD-PACK-/220521429127) m
I tried using that gasket metal recently and wish I hadn't bothered. It lasted about a month then blew the inside fibres out and left me with the 2 metal skins. Get a proper one.
Quote from: "Davegtst"I tried using that gasket metal recently and wish I hadn't bothered. It lasted about a month then blew the inside fibres out and left me with the 2 metal skins. Get a proper one.
Thats my problem, they dont do a gasket for it!!!!!!!! s:? :? s:?
I cant understand how its meant to work without one, but the installation manual doesnt reference one and Nath who also had a tte said there was never one on his.
That's the stuff, I used it for my turbo to manifold gasket
Thanks problem ive got is ive only got till Tuesday to get back to the test centre so I cant order it online.
not sure it would work for my apllication anyway as the mating faces are not flat theyre conical.
Sounds like it was design to have a crush gasket in. I know its not the best idea but you can get exhaust paste that you need to heat up in hot water before using. That stuff is very good at sealing. Halfords might sell it?
Good call, I reckon thats gonna be my only option considering the time frame.
Rbuckingham, I have just looked at the photos on your profile, is that a rotrex supercharger? Did you run that before the turbo?
No he sold it before he was able to get it installed properly.
Exhaust paste was going to be my suggestion but I didn't bother mentioning because it shouldn't really need it. I can imagine it's going to be pretty difficult to get it around the whole join given it's location s:? :? s:?
Yep as said never installed it, but it was a trd / vortex supercharger not a rotrex.
Well ive stripped it all out so access to it isnt a problem, 1st lucky break, turns out my neighbours relative is a mechanic and he kindly gave me some high temp silicon gasket, ive applied it and will have to wait 24 hrs for it to cure. Its o2 sensor safe and is fully flexible, little wortied about it being blown out so i put a metal zip tie in it while it was still wet so it will cure in the join and around the tie, hopefully it will hold it in. Fingers crossed again that this will work.
Sounds like a good plan. How bad was it blowing?
Fingers crossed mate
Apologies in advance in case I am way off. (I believe we are talking TTE?)
If we are talking TTE
the following in the refrence section may be helpful in the long term if not before the re-test.
http://www.mr2roc.org/Repository/misc/referencelibrary/tteturbo.pdf
Page 11 shows the gaskets and page 20 - 21 gives the part numbers. Might be able to extract something from MR T armed with their own info.
Might be worth a look.
Sorry if wasted your time.
J
Thanks ardent for the link, but theyre just the gaskets for the main cat pipe ends. Theres nothing for the the pre cat pg 10. Appreciate your help though s:) :) s:)
Nath ive got a really blurry pic of it, the white bit in the middle was liquid solution which instantly foamed up. So pretty bad. Cant imagine im the only person whose tte did this with no gasket, just mine is very extreme.
Thanks Steve btw congrats on the 1year award s:lol: :lol: s:lol:
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Foaming away Almost instantly s:roll: :roll: s:roll:
Is it missing from the exploded diagram?
goes parts 10-1 to 10-8. Does not show 10-7 on page 10.
On page 21 does list a 10-7 Gasket exhaust pipe. 17451-22060
Possibly maybe ???
I thought it was at first to, but after a search it seems its the gasket to connect the main cat to back box
Ha well a big fat screw you to the designer of that gasket less joint s:evil: :evil: s:evil: Its sealed s:bounce: :bounce: s:bounce:
2 years of faffing around and trips to so called mechanics later and its fixed.
For how long, time will tell. Long enough to get through the test I hope s:D :D s:D
As its a massive pita to access, on top of the sealant I packed round the join with heat wrap and steel ties. Cant be having to go through all that again any time soon s:roll: :roll: s:roll:
Any one who owns a tte turbo these are your best friends if you need to get the precat off. Modified (cut the ring end off )13mm spanner and small ratchet.
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Impossible to access without the shortened spanner.
Have you seen this new topic :
l viewtopic.php?f=11&t=54346 (http://mr2roc.org/phpBB3/viewtopic.php?f=11&t=54346) l
This seems to report O2 sensors doing exactly what yours are doing ie one constantly running at 0.7 to 0.8v. Looks like this may be normal?
Hi lamcote heres a link for correct 02 operation
m http://www.aa1car.com/library/o2sensor.htm (http://www.aa1car.com/library/o2sensor.htm) m
may aswell put in here as reference if anyone needs it.
no mine was definitely dodgy, I swapped it out for the new one and the readings are much better. Just for a further comparison i put the dodgy one in the other sensor hole and the readings for that bank went rich again. As in link sensor should fluctuate as in the 1st wave pattern to be operating correctly.
Result s:bounce: :bounce: s:bounce:
Mot passed, hard fought victory but got there in the end.
Now I can actually get out and drive it.
Thanks all for the help along the way s:bowdown: :bowdown: s:bowdown:
Great! So the cause was a faulty sensor AND a leak?
Does the car feel any better or can't you feel it?
Just in time for the nice weather too s:) :) s:)
Glad youve got it sorted mate s:) :) s:)
Nice one Dan, well done for preserving.
Just need to to get the coilies on and you can really enjoy it! :-) :-) :-)
Thanks all.
yeah I think the leak(s)were causing it to run rich which in turn ruined the sensor as it was really dirty.long term fuel trims are all back at +2 from around -10 so massive improvement.
Can really notice the difference especially when boosting, weird because I think its seems a fraction slower but has more torque, probably due to the more restrictive cat being on.
yeah next spanner session is the coilovers, i know what im doing with them s:) :) s:) need a few weekends off to enjoy the car first s:D :D s:D
Well done, it was worth sticking at it.
Quote from: "rbuckingham"Well done, it was worth sticking at it.
All I can say is its a good job I
really like the car, as any other motor might of been sold on s:wink: :wink: s:wink:
Thank god!
s:) :) s:)
Praise be!!!
Nope not god it was me lol and my very understanding missus who gave up her easter holiday weekend to keep me in cups of tea s:D :D s:D