OBDII reader

kanujunkie · February 16, 2007, 20:52

Quote from: "Liz"
Quote from: "kanujunkie"
Quote from: "Liz"Does it cost?

nope, its FREE!

At work at moment, can you tell how busy I am !! Will do it moro and if it works will bring along in the evening if you like?

ooh,, yes please Lizzy s:D

s:D

Leeber · February 17, 2007, 16:50

Well that was short-lived. The CEL's back on, same code. Looks like a job for Mr T then, I just hope they don't notice that the car doesn't have a cat.

Liz · February 17, 2007, 17:02

Quote from: "Leeber"Well that was short-lived. The CEL's back on, same code. Looks like a job for Mr T then, I just hope they don't notice that the car doesn't have a cat.

Hmm think they might, I was waiting for my car when it had the oil flush done, it was parked next to the viewing window, I looked up to see 4 toyota technicians with their heads under the bonnet looking at the turbo!

aaronjb · February 17, 2007, 17:04

Maybe they were confused why you were keeping it with the spare tyre..... s;)

s;)

*hides* (Sorry Liz, couldn't resist!)

Anonymous · February 17, 2007, 18:06

I was thinking the same thing about the cat. I plan to tell them that it is part of the TTET kit if they ask as there is already a pre cat on it but really what are the chances of some MR T 18 year old spotty mecanic actually knowing what it is ?

Anonymous · February 18, 2007, 22:36

Well guy's I sorry to report - I'VE GOT A CEL s:cry: :cry: s:cry: s:cry: :cry: s:cry: Not sure what the code is yet, I'll have to wait until next week now. Guess what I fitted on Saturday - a SP de-cat pipe, I've reset it twice now - OK at first, give it some serious s*** no problem, run softly softly it's back.

Going to see if I can get a bush made, I've looked at the US for a "Spark Plug Non Fouler" but they don't seem available, unless any one over here knows where to get one from.

Might have to bring the Apexi forward a bit quicker at this rate.

Rob.

Liz · February 18, 2007, 23:38

I was under the impression that SP had included some sort of system that made the sensor sit further back in the pipe in anycase? I explain it better earlier on in this thread..

BenF · February 19, 2007, 00:57

FWIW .. I did some datalogging of the OBD-II O2 sensor outputs from a standard MK3 Roadster, and compared those with mine which has no cats at all.

Main difference is that the post main cat sensor's output only varies slowly with time - and only changes gradually from rich to lean with time. if you removed the main cat, it would definitely throw a CEL as this sensor would instead see the rapid changing in rich/lean as the ECU fine tunes the fuel/air mix at steady throttle.

I've tried various ways to bodge the sensor output to fool the ECU into thinking everything is fine (and so get rid of the CEL) but I've come to the conclusion the only thing to to is to build a small box of electronics that mimics the 'happy' type of output from the post-main cat sensor when the cat is present.

That way, even if you're running no cats at all, you shouldn't get a CEL as the ECU is fooled into thinking the O2 sensor output is good.

I've done the basic paper design of such a post-main cat O2 sensor circuit - for budding amateur Electronics bods - a classic NE555 timer, square wave output, but on/off cycle time of 80-100 seconds, swtiching between between 0v and 0.9v is what you want - but I need to find time to build, test and then install it into my Roadster.

Does anyone have a detailed pin-out of the 2003 ECU that I could use to potentially test this out with ...?

loadswine · February 19, 2007, 01:09

Clever stuff indeed matey. Hope you get it to work okay. Someone is bound to have the info.

Liz · February 19, 2007, 10:54

This is the reasoning behind the code, Matt drew the picture, I done the writing!!

Firstly Matt mentioned this, this is his diagram and my writing trying to explain it s:oops: :oops: s:oops: . Apparently when they developed the SP exhaust - the O2 sensor there kept throwing a code - which one I don't know - yes I should of asked. So in order for this not to throw a code they put the sensor a little further back from the airflow in what they called an antifouling. Therefore, the O2 sensor is not reading the amount of air that it would normally and Matt believes that this is the reason why that it is **reading** that it is running lean when in fact it isn't due to the sensor is set back and not picking up the full air flow - does that make sense? Here's the diagram..

loadswine · February 19, 2007, 11:18

All workshop manuals should be like that! s:)

s:)

Leeber · February 19, 2007, 11:28

That's pretty much the way Matt explained it to me as well Liz. I'm not 100% certain that the SP pipe is to blame in my case. It's a month since the TTET install and O2 sensor replacement, it's only started throwing up the codes in the last few days. Also, the code indicates that there is a problem with the circuit, not that that the parameters being sensed are out of limits. My (possibly incorrect) assumption is that if the O2 sensor was detecting too much or too little O2 in the exhaust gases it would give a different fault code e.g. the P0420 code that you were getting Liz.

BenF · February 19, 2007, 11:35

Cheers Liz, love the diagram - know exactly what you mean. s:D

s:D

I think a few people have used the anti-fouling trick, but it doesn't always 100% sort the problem. ISTR its basically a spacer (often used by motorbikes for spark plugs) to lift the sensor out of the gasflow in the exhaust. When it is protected from the gas - less will flow past it, so giving a more slowly varying rich/lean exhaust gas content.

This setup is good as you're still using the sensor to measure the exhaust gasses - I seem to remember Sean used this with his Hass setup, but found it would still throw a CEL from time to time.

Unfortuantly for me, being completely Cat free the only real option is to do some kind of 02 Sensor emulator.

I don't think the ECU uses this output for anything other than checking the emissions are OK (and to send you to a dealer for a new sensor/ main cat if not) so I don't expect to run into other problems by doing this.

I've got to sort the rear calliper on mine first, but I'll be looking to build and test the circuit in a few weeks time ...

spit · February 19, 2007, 11:55

Quote from: "BenF"Does anyone have a detailed pin-out of the 2003 ECU that I could use to potentially test this out with ...?

Ben - you have email (s)

Liz · February 19, 2007, 12:28

Quote from: "Leeber"That's pretty much the way Matt explained it to me as well Liz. I'm not 100% certain that the SP pipe is to blame in my case. It's a month since the TTET install and O2 sensor replacement, it's only started throwing up the codes in the last few days. Also, the code indicates that there is a problem with the circuit, not that that the parameters being sensed are out of limits. My (possibly incorrect) assumption is that if the O2 sensor was detecting too much or too little O2 in the exhaust gases it would give a different fault code e.g. the P0420 code that you were getting Liz.

Thing is with mine to fix it I replaced the MAF, so it was that giving dodgy readings rather than the O2 sensor...as your car is practically brand new I would of thought your MAF would be ok.

Anonymous · February 19, 2007, 14:44

Interesting points, I have spoke to Matt this morning and yes he said exactly the same as you Liz, the big difference as Ben as pointed out is we are both cat free, the TTE as a cat fitted so that's why you only need a small amount of repositioning of the third sensor.

I'm looking at having a bush made in the mean time, I know I've not had the code confirmed but I thought it best to get something moving - just in case.

The car itself is running fine, and boy does it rev, what will be the effect of running with the CEL, does it affect the learning of the ECU, how long can you run on it for?

Thanks
Rob

markiii · February 19, 2007, 14:49

3rd o2 cel is just a warning for you, teh ecu does nothing about it.

only issue is if another cel pops up you won't see it.

other than youi can run it that way ad infintum

Anonymous · February 19, 2007, 14:54

Quote from: "markiii"3rd o2 cel is just a warning for you, the ecu does nothing about it.

only issue is if another cel pops up you won't see it.

other than youi can run it that way ad infintum

Cheers Mark, I've just brought one of the code readers off Flee bay, once I return on Friday I can start the ball rolling.

It'll all be sorted when I fit the Apexi, but need to build the funds up first s:wink: :wink: s:wink:

Rob

BenF · February 19, 2007, 19:59

Quote from: "markiii"3rd o2 cel is just a warning for you, the ecu does nothing about it.

only issue is if another cel pops up you won't see it.

other than youi can run it that way ad infintum

s:twisted: :twisted: s:twisted: Yep, that's the way I've been running mine for a while. I did get an OBD-II reader and some software for my iPAQ so I could read the error codes and reset them every so often and check all was Ok.

I am still tinkering with the idea of setting something permanent up that allows me to monitor the output from the ECU in real time.

Anonymous · February 20, 2007, 16:03

My OBD II arrived today and I have read the code as P0136 O2 Sensor malfunction (Bank 1 Sensor2) so it's the same as Lee's. The car is back at Mr T's on Thursday to have new O2 sensor's fitted and hopefull that will have sorted the problem.

Leeber · February 20, 2007, 18:37

Hmmm... that's quite a coincidence. Would you mind keeping us posted on how you get on with this? I'm not planning to get mine sorted for a couple of weeks, if replacing the sensors doesn't do the trick you'll know by then I guess. Good luck with it mate.

Anonymous · February 20, 2007, 19:02

Will do, after speaking to Matt he is convinced that it is nothing to do with the de-cat pipe and I have been doing a lot of searching and it seams that the O2 sensors are a common problem so hopefull when thay are changed this will cure the problem.

Anonymous · February 26, 2007, 19:50

Just a quick up-date.

My reader arrived today, put it on the car - guess what I've got a P0420 s:lol: :lol: s:lol: Reset the ECU plus I fitted my O2 extension bung over the weekend so lets see how long this lasts.

Going to Hyper Sport on Wednesday for a Dyno s:shock: :shock: s:shock: will report back with the figures.

Rob

philster_d · February 26, 2007, 19:59

The ecu logs the last few codes it might not be new.

Anonymous · February 26, 2007, 20:33

Quote from: "philster_d"The ecu logs the last few codes it might not be new.

It listed 3 which is correct Phil, they were all 0420's, this will be the first time I've re-set it with the new extension bung fitted, so it will be interesting to see how long it lasts. Nice little reader by the way, I like the fact it clears the fault for you.

Rob