nyzrox
Member
Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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Hi,
Looking for maybe some advice or something, i know or have read somewhere the Z18XE ECU's are common to failure?
Basically, the cars failed due to Emissions, here are some resaults
Last Year:
Fast Idle Test,
CO: < 0.20% Vol (Limits) - 0.00% Vol (Actual Value)
Natural Idle Test,
CO: < 0.30% Vol (Limits) - 0.00% Vol (Actual Value)
This Year:
Fast Idle Test,
CO: < 0.30% Vol (Limits) - 4.79% Vol (Actual Value)
Natural Idle Test,
CO: < 0.50% Vol (Limits) - 9.09% Vol (Actual Value)
So, from last years resaults to this year something major has happened. The ECU has been reporting the O2 Sensor1 Bank1 as faulty, it was replaced, it still persisted to say this was faulty, so i put another on... It still said it was faulty so i gave in and left Management light on for the past 6 months. AFM has also been replaced.
Today, i got those figures from the MOT. We tried putting a 1.5v Battery on +/- of the Lambda sensors connector (So basically disconnecting the lambda and putting a battery on +/-) figures were still the same.
We plugged in the scanner, the lambdas were reading 4.12v thats both PRE and POST. Reved the car a couple of times, the lambda readings went to 4.30v ... again PRE and POST.
Could it be possible my ECU is shot causing this issue being that it repeatedly reports a faulty sensor.
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modded_corsa
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Registered: 9th May 03
Location: Middlesbrough
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you using OE/ GENUINE parts or using a universal lambda probe?
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nyzrox
Member
Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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Genuine from VX
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Adam-D
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Registered: 11th May 02
Location: Cheshire
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im more sceptical your car put out zero emssions last year
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Warren G
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Registered: 14th May 06
Location: Kent
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cat?
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nyzrox
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Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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quote:
Originally posted by Adam-D
im more sceptical your car put out zero emssions last year
I just got the readings off the printout.
quote:
Originally posted by warren.g
cat?
Well, it doesnt rattle or anything like that.
Maybe im thinking if ECU is gone, its killed the lambda again causing the engine to run rich therefore knacking the CAT?
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Warren G
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Registered: 14th May 06
Location: Kent
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there are two o2 sensors
whats the lambda reading?
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nyzrox
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Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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See #1
quote:
e plugged in the scanner, the lambdas were reading 4.12v thats both PRE and POST. Reved the car a couple of times, the lambda readings went to 4.30v ... again PRE and POST.
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Warren G
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Registered: 14th May 06
Location: Kent
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not on the reader -
on the emsissions machine
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nyzrox
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Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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Oh, uh im not sure mate.
I dont remember, only thing i have is the printout now of the tests.
Youd think on the Z18XE Bank1 Sensor1 being PRE-CAT? Or am i being stupid and its POST-CAT thats the knackered sensor?
Would be disconnecting the coolant sensor then doing the emissions get it threw, as this should cause the engine to run lean shouldnt it?
[Edited on 20-06-2008 by nyzrox]
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Warren G
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Registered: 14th May 06
Location: Kent
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bank one sensor 1 - pre cat
bank one sensor 2 - post cat
check to see the post cat sensor isnt runing rich, should be a round 450mv and not flucate much
discccounting the coolant temp sensor will prob make it worse
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nyzrox
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Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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Man all i need is to make it pass the bloody mot.
Will not disconnecting the coolant sensor make it run lean?
It always says sensor1 is out. But its been replaced a couple of times.
How can i test to see if the post cat sensor is running rich, i have a multi meter, or do i need to use the emissions machine thing down the garage?
Is it worth replacing both lambda's, AFM... try again. If still not at right, is it work ECU, or CAT?
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Warren G
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Registered: 14th May 06
Location: Kent
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dunno, i only just tech2!
well without looking at it, i couldnt say what it is
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nyzrox
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Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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il try taking coolant sensor off.
IF that doesnt work,
new lambda's (pre and post), AFM - Try again.
IF still same,
ECU - Try again.
If again, only can be the cat.
Unless being the ecu is reporting lambda's been knacked for about 11 months now the engines been running rich for so long its knacked the CAT? This a possibilty?
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Warren G
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Registered: 14th May 06
Location: Kent
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need to check the o2 readings tbh
you can remove the o2 sensor and down pipe to see if the cat looks broken up
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nyzrox
Member
Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
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Ive had the manifold off many times in the past and seemed fine, last time it was off was 4 months ago.
in my mind i think the cats fine...
BTW, PM me some details to your TB's for z18xe, are you converting to cable throttle?
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Warren G
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Registered: 14th May 06
Location: Kent
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i personaly dont think its the cat
could be a number of things, but you have stated the most likely items, and you have replaced them
so not sure
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ainsley_brader
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Registered: 24th Mar 02
Location: Tattershall, Lincolnshire
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A o2 sensor voltage of 4.12 or whatever tells you nothing with o2 you are looking for a switching signal both pre and post.
If you have replaced the afm and o2 sensor with genuine parts and it has made no difference then there is little point in changing them again atm.
The post cat sensor i would ignore for the moment tbh. It has more to do with checking the gat efficiency than actually adjusting emissions.
If the computer thinks there is a problem with the precat lambda then thats where you need to start looking.
You need to test the lambda properly to see if it is switching as it should if it is then you have to look at what is fooling the ECU. Earths/air leaks etc!
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nyzrox
Member
Registered: 19th Jan 06
Location: Nottinghamshire Drives: MK4 Astra GSi
User status: Offline
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Problem = ECU. Earth is ****ed on it by the looks, its been looked at for 5 hours. Ground loop, seems.
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