J-Spec Stock ECU

[Soop Dogg]

Just took my car for MOT.  Everything was going swimmingly until the last bit....emissions.

 

It seems it is being massively over-fuelled.  The CO levels were over 8% where they should be under 0.3%!!!:o :o :o

 

Everything else was fine, but what can I do about this?  Can the ECU be adjusted by Toyota to rectify this or could it be a different problem?  Are the NA and TT ECU's very different? (As I suspect they would be)  Would an aftermarket ECU be a better idea?

 

 

Someone pleeeaaasseee help.....I'm in a panic now and want some good news!!!

[Guest Ash]

 

 

Check some idiot hasn't performed the "12v Fuel-Pump Mod" given on the Yankie website. Or your Oxy sensor may be *uggered but I suspect the ECU would show a fault code. You could try seeing if any codes are stored before jumping to conclusions. But there is no adjustment on the ECU just to answer your point.

 

Yours,

J

[Soop Dogg]

Cheers, Ash.

 

Re the 12V Fuel Pump thing, do you have a link to that?

[Guest Ash]

 

 

Look I gotta rush right now but you'll find it on the MKIV.com website. If my memory serves me correct I think Pete Betts had the same problem after he did the mod but I might be mistaken.

 

But I can categorically confirm there is NO ECU adjustment.

 

If you want something to do tonight,while there is still daylight, go to the MKIV.com website and lookup how to check for any fault codes. It only takes a bit of wire.

 

Yours,

J  

[Alex]

http://www.mkiv.com/techarticles/12v_mod/12v_mod.htm

 

Ta da!!

[Soop Dogg]

Thanks Alex.  By the way, you don't happen to have a spare ECU kicking around, do you?

[Alex]

regular spare parts bin am I??

 

Nope sorry...

[Matt Harwood]

Take this with a massive lorry full of salt as I am certainly no expert by a long way, (Was that enough of a personal disclaimer )

 

I used to have a Sierra Cosworth that failed because the emissions were too high. It turned out that the airfilter was mucky. Changed the filter and it passed straight away. - Could have been coincidence but it worked.

 

Could a bad air flow make the fuel mixture read higher? - Dunno but it sounds feasable

 

OK, I'm going now 'cause it feels like I'm talking to myself, (Or talking crap One or the other!)

[Alex]

I was going to suggest using some injector cleaner and de-coke stuff...

 

if the O2 sensor is dirty can you clean it or do you have to replace it?

[Soop Dogg]

I was thinking of just taking the air filter out just for the MOT to help drop the figure a bit.  But look at how rich it seems to be running, nearly 30 times the LIMIT.  And there lies my problem, it isn't just running at 30 times normal mixture, but 30 times the limit!!

 

I'd like to borrow an ECU for an hour and have the emissions checked before I spent £X000 on a replacement ECU.  If a sensor was up the wall, wouldn't the ECU pick up the fact that there was a problem because all the other inputs were showing that the engine is at idle and the throttle is closed yet we're pumping in shedloads of fuel?  It just seems very strange to me that no warning is being given of a problem and the system is putting in this amount of fuel.

 

I think it would be unusual for the ECU to have become corrupted rather than breaking down in some way either causing it to stop functioning completely or to at least flag up a problem.

 

I'll be checking out this 12V mod tomorrow morning as that sounds feasible.

 

Any other thoughts will b egreatly appreciated.  Mr Betts, are you about?  Are there any checks I can get done?

[matt]

Quote: from Matt Harwood on 10:46 pm on April 5, 2002[br]

 

It turned out that the airfilter was mucky. Changed the filter and it passed straight away. - Could have been coincidence but it worked.

 

 

Spot on  Matt .............. thats the first thing I'd check

[Guest Martin F]

 

Does the J-spec have an airflow meter ? I don't think they do.

 

You could also check out the throttle position sensor, there is an alignment procedure for this somewhere. Let me know if you need me to take a photo.

 

Also temperature sensors can cause the car to run rich if they think things are cold when they aren't. They are all plugged in OK aren't they ? Left hand front side of the block where the top rad hose connects to.

 

Also a leak in the inlet piping could cause problems, look for split hoses.

 

There really is a number of things and it's hard to know where to start. You may want to check the state of teh plugs and see if they have heavy deposits on them indicating the car has been running rich for sometime.

 

 

 

[GavinL]

Quote: from Alex Holdroyd on 10:56 pm on April 5, 2002[br]

if the O2 sensor is dirty can you clean it or do you have to replace it?

 

Leave it overnight in lemon juice I heard

[Guest Mycroft]

Your diagnostics can detect whether the O2 sensor is out.

 

I agree with Martin, the most likely cause is cold running when warm, check the sensor is giving the correct signal, a simple Ohmeter is all you need.

 

The check is in the WSM.

[THOR Racing]

>If my memory serves me correct I think Pete Betts had the same

>problem after he did the mod but I might be mistaken.

 

This is correct. I did the mod and unlike others my fuelilng went skyrocketing to around 8% as well.

 

I think my stock fuel pressure regulator is a bit faulty (still haven't changed it :-( )

After removing the 12V fuel pump mod the emmisions dropped to about 0.5% (still above the 0.3% limit unfortunately, but with patience and a kind MOT guy we just get through now)

 

Check the O2 sensor as well (as already stated). I've cleaned mine by emersing in lemon juice over night. No noticeable difference but didn't hurst anything.

 

The Jap spec don't have a mass air flow meter only manifold air pressure sensors and these are not used for idle fueling.

 

What MPG do you get? And what were the other levels from the MOT?

 

If it's just excessive fuel you're using the hydrocarbons will be within spec still (mine were)it was only the unburnt fuel which was high hence high O2 percentage.

 

The other figures can normally give a clue as to the reason for the massive fuel usage.

 

 

Regards

 

Pete

 

[Soop Dogg]

Thanks everyone for all the advice.

 

I'm looking at error codes this morning.  Can anyone give me locations for the O2 sensor and the fuel pressure regulator.(Don't have a workshop manual)

 

Also, if anyone knows what resistance I should see across the O2 sensor I would appreciate that too.  (Am I just being a pain in the a*se now?)

 

Cheers,

 

Brian.

[Soop Dogg]

Quick update:

 

No trouble codes in the ECU.

No mod been preformed to fuel pump ECU.  Fuel pump input voltage at idle: 8.6V....normal.

 

Just something I came across while surfing for info,  when you guys select 'manual' on your auto box, does your box select overdrive when on a light throttle at speed?  The reason I ask is that apparently it should do so when warm.  However, mine never gets into overdrive from 3rd no matter how warm it is.  There is a protection system which stops it changing up into overdrive when cold.  This temp input is from the coolant temp sensor.  If mine has failed to cause it to stay in 3rd,  could this also make the car run on 'cold' fuelling when warm?

 

However, does this mean that the temp gauge uses a different coolant temp sensor as my gauge seems to act fine?

 

 

[Matt Harwood]

Mine never goes into 4th/overdrive when in manu mode either. Never has, hot or cold.

[Phil Wall]

 

Brian,

 

I only have a UK manual, but according to that the Fuel pressure regulator is underneath the throttle body, looks like you have to take the TB off to get at it, there is no data just physical check.   Martin might be able to scan the appropriate pages (EG 308 to 312) to you, sorry I have no scanner at home.

 

However the VSV for fuel pressure control, which is mounted just below the throttle cable bracket should have a resistance of 33- 39 ohm at 20 degree C

 

I the main Oxygen sensor on the Jap spec is on the mainfold just before the first cat, the procedure for checking is fairly complex and too detailed to post here, again you need a scan of pages EG 376- 378.

 

[Phil Wall]

In MANU mode the auto locks into 3rd in D there is no 4th or overdrive, according to my handbook.

 

In normal mode ie MANU off, the box will only change up to 4th if it is warm and OD is on.

 

If you use MANU and the box gets too hot the MANU light will flash and the box will revert to normal ie automatic changes.

 

[Soop Dogg]

Thanks for putting me right, i obviously misunderstood what I read and thought me box wasn't functioning correctly, which it obviously is.  Well that presumably means the temp sensor is working.  

 

With regard to what Mycroft suspected, i.e. cold running when warm.

When started from cold I get the usual increased idle speed which returns to the normal idle after a few minutes.  If it thought it was still cold, surely the idle speed would stay high?

 

The MOT emission figures are as follows:

Fast Idle Test:  

                         CO  8.86%  (Limit: 0.3%)

                         HC  236ppm(Limit 200)

                         Lambda 0.76(Limit 0.97-1.03)

 

Second Fast Idle Test:

                          CO  2.74%

                          HC  103 (PASS!!!)

                          Lambda (.92)

 

Natural Idle Test:

                          CO  1.77%

 

:( :( :( :(

 

 

 

[mikeh]

Hi  to all,

 

First post...      My emissions for MOT were;

 

Fast Idle Test:  

CO          0.64 % Vol               Fail

HC          51 ppm                     Pass

Lambda  1.010                

 

Second Fast Idle Test:

CO          0.19%                        Pass

HC          8 ppm                        Pass

Lambda  1.001

 

Natural Idle test;

CO          0.33                 Pass

 

That’s with Blitz ECU, Downpipe and HKS Super Dragger on an Import TTGZ.

At least that’s all I know about…

 

Hope this is some help,

 

Cheers

Mike

 

[Guest Mycroft]

The Soarer has an elevated rpm device which does that 1200,1100,1000 thing but a second device enrichns the mixture.

 

My mistake, I thought the Supra would have the same.

 

That's a pity, looked a good candidate to me.

[Guest Martin F]

Can somebody help me out here, that Lambda figure on the MOT test, is that a voltage taken from your own lambda sensor or is it one taken from the stations own test machine ?

 

Because if it's from Brian's own then it's showing that his sensor is indeed reading a rich condition (which should eliminate the oxygen sensor), but for some reason the ECU is not correcting this or is not able to, which in theory should throw up a fault code.

 

Brian, you can read your own oxygen sensor voltage direct from the diagnostic port (OX1) but if somebody can answer this for me it will save you the job.

 

As for the fuel pressure regulator you can test this but you need a fuel pressure gauge and attach this using an adapter to the fuel rail. My crystal ball tells me you just aren't going to have one of these lying around.

 

However there should be a vaccum pipe connected to the fuel pressure regulator and it is worth checking that this hasn't split or come off. If you had this on the gas analyser i would suggest bypassing the VSV for the FPR and see if that makes any difference.

 

This is a very hard problem to diagnose remotely (damn feedback circuits), but through a process of elimination we may get there.

 

 

 

[Phil Wall]

Surely the lambda figure must be from the test centre machine, otherwise it would be possible to rig the test.