any ideas ?

wotugonado · March 31, 2015, 22:38

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% ?

lamcote · April 1, 2015, 09:45

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.

wotugonado · April 1, 2015, 12:42

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

s:D
We shall see if that helps.........

To be continued s:D

s:D

lamcote · April 1, 2015, 13:22

Hope it helps, good luck

wotugonado · April 1, 2015, 13:24

Hope so, thanks for all your input so far.

nathanMR2 · April 1, 2015, 14:19

Fingers crossed

wotugonado · April 1, 2015, 15:06

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.

nathanMR2 · April 1, 2015, 17:47

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

wotugonado · April 2, 2015, 22:25

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.

nathanMR2 · April 3, 2015, 09:00

That's p1ss poor mate.

At least doing yourself you know can get everything how it should be.

wotugonado · April 3, 2015, 09:52

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:?

nathanMR2 · April 3, 2015, 10:06

Sadly or rather fortunately that's generally the case. There's a lot of knowledge about these cars around here

wotugonado · April 3, 2015, 18:22

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.

Anonymous · April 3, 2015, 23:16

You can get metal gasket paper that you can just cut and make a gasket

wotugonado · April 4, 2015, 00:18

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 ?

lamcote · April 4, 2015, 06:56

Is this it?

m http://www.ebay.co.uk/itm/SHEET-METAL-E ... 0521429127 m

Davegtst · April 4, 2015, 08:29

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.

wotugonado · April 4, 2015, 09:26

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.

Anonymous · April 4, 2015, 09:57

That's the stuff, I used it for my turbo to manifold gasket

wotugonado · April 4, 2015, 10:03

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.

Anonymous · April 4, 2015, 10:48

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?

wotugonado · April 4, 2015, 10:57

Good call, I reckon thats gonna be my only option considering the time frame.

lamcote · April 4, 2015, 11:59

Rbuckingham, I have just looked at the photos on your profile, is that a rotrex supercharger? Did you run that before the turbo?

nathanMR2 · April 4, 2015, 13:13

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:?

Anonymous · April 4, 2015, 13:40

Yep as said never installed it, but it was a trd / vortex supercharger not a rotrex.