Failing emissions Celica ST20
Discussion
Morning all,
I've recently acquired a slightly modified Celica which continues to fail it emissions test at different local test centres. the various tests are shown in the pictures below.
The first test, no new parts installed.
The second test, new lambda.
The third test, new cat (plus lambda from above).
My comments are:
1. I've been told the vehicle was previously remapped, surely if it had been then it would already be tuned for optimum settings and therefore would easily pass emission tests.
2. I've run my hand up and down the exhaust and felt or heard no leaks.
3. I've checked the aftermarket cone air filter and pipe work to the throttle body for leaks, again nothing found.
4. I've pulled out the fuses to 'reset' the ecu.
I'm at a loss of what to check next, I was wondering if the new cat needs some mileage under it to 'break' it in. I am thinking of a remap, could anyone recommend anywhere in the Portsmouth area?
Mike
I've recently acquired a slightly modified Celica which continues to fail it emissions test at different local test centres. the various tests are shown in the pictures below.
The first test, no new parts installed.
The second test, new lambda.
The third test, new cat (plus lambda from above).
My comments are:
1. I've been told the vehicle was previously remapped, surely if it had been then it would already be tuned for optimum settings and therefore would easily pass emission tests.
2. I've run my hand up and down the exhaust and felt or heard no leaks.
3. I've checked the aftermarket cone air filter and pipe work to the throttle body for leaks, again nothing found.
4. I've pulled out the fuses to 'reset' the ecu.
I'm at a loss of what to check next, I was wondering if the new cat needs some mileage under it to 'break' it in. I am thinking of a remap, could anyone recommend anywhere in the Portsmouth area?
Mike
As lambda looks off,
Check the ignition, plugs, leads, distributor and rotor arm, etc.
Check for boost leak from turbo to head, holes in inter cooler, etc.
Check for vacuum leak from air filter to turbo.
Check MAF and O2 sensors.
Once lambda is fixed, then we can tell if the cat is working on the CO.
Check the ignition, plugs, leads, distributor and rotor arm, etc.
Check for boost leak from turbo to head, holes in inter cooler, etc.
Check for vacuum leak from air filter to turbo.
Check MAF and O2 sensors.
Once lambda is fixed, then we can tell if the cat is working on the CO.
Hygt,
Thanks for your comments, the car has a 3SGE engine (non turbo) so some of your comments won't apply.
I'll be changing plugs and I discovered this afternoon that I need a new cam cover gasket as my plug bores had oil in them indicating a leak from the gasket above.
I'm quite friendly with a local tester and his emissions analyser so I can try a few things and see what makes the biggest difference.
MJ
Thanks for your comments, the car has a 3SGE engine (non turbo) so some of your comments won't apply.
I'll be changing plugs and I discovered this afternoon that I need a new cam cover gasket as my plug bores had oil in them indicating a leak from the gasket above.
I'm quite friendly with a local tester and his emissions analyser so I can try a few things and see what makes the biggest difference.
MJ
pompeymj said:
Hygt,
Thanks for your comments, the car has a 3SGE engine (non turbo) so some of your comments won't apply.
I'll be changing plugs and I discovered this afternoon that I need a new cam cover gasket as my plug bores had oil in them indicating a leak from the gasket above.
I'm quite friendly with a local tester and his emissions analyser so I can try a few things and see what makes the biggest difference.
MJ
Sounds great. I run a SW20 MR2 Rev 3 95/N so also a 3SGE. I had rocker cover gasket changed as well. They are fundamentally reliable. My car has done 191,000 miles and I mostly used it for country road driving events and track days. The engine and gearbox are still original. Thanks for your comments, the car has a 3SGE engine (non turbo) so some of your comments won't apply.
I'll be changing plugs and I discovered this afternoon that I need a new cam cover gasket as my plug bores had oil in them indicating a leak from the gasket above.
I'm quite friendly with a local tester and his emissions analyser so I can try a few things and see what makes the biggest difference.
MJ
Start with pulling the fault codes and change only the cheapest parts first.
You may also want to change your title to ST202 as yours is a N/A.
Afternoon HYGT,
The Celica is just over 136000 km so nowhere near your MR2. The car is only going to be used at weekends really as I've got a couple of others for daily use, I also limited the policy mileage.
I've had no error codes appear (as in the EML isn't on) although it hasn't been plugged in for a diagnostics, there may be a couple of codes that aren't forcing the EML on.
I did originally have the title as ST202, I must've hit backspace before posting it. It's my first post on here and I can't seem to change the title.
I've ordered the gaskets from Toyota and I have a copy of the 3SGE manual which makes the whole process even simpler, I'll have to wait until the weekend though as the gasket won't be with my local dealer until tomorrow and I have to do my car work outside on the driveway.I am wondering if the cover has been off before as the fixings are bolts and not screw heads as described on other instructions I've seen. I'll be taking the opportunity to clean everything while it is off the car which should have an impact on running / breathing of the engine.
I'll report back over the weekend.
MJ
The Celica is just over 136000 km so nowhere near your MR2. The car is only going to be used at weekends really as I've got a couple of others for daily use, I also limited the policy mileage.
I've had no error codes appear (as in the EML isn't on) although it hasn't been plugged in for a diagnostics, there may be a couple of codes that aren't forcing the EML on.
I did originally have the title as ST202, I must've hit backspace before posting it. It's my first post on here and I can't seem to change the title.
I've ordered the gaskets from Toyota and I have a copy of the 3SGE manual which makes the whole process even simpler, I'll have to wait until the weekend though as the gasket won't be with my local dealer until tomorrow and I have to do my car work outside on the driveway.I am wondering if the cover has been off before as the fixings are bolts and not screw heads as described on other instructions I've seen. I'll be taking the opportunity to clean everything while it is off the car which should have an impact on running / breathing of the engine.
I'll report back over the weekend.
MJ
Afternoon,
I managed to swap the gasket and check all pipe work yesterday. I did find a couple of slightly split hoses which I replaced, these were only split at the junction with the connection. I left the gasket and the FIPG to settle, the FIPG needed 24 hours to set. Ran the car up today with no issues and no differences in its running behaviour so I figure that it will probably still fail emissions. I'll get it in after the bank holiday to confirm.
My only other thought is to swap the Denso lambda for a genuine Toyota one as everything else appears fine.
I'll report back with more updates once I know how it stands on the testing front.
MJ
I managed to swap the gasket and check all pipe work yesterday. I did find a couple of slightly split hoses which I replaced, these were only split at the junction with the connection. I left the gasket and the FIPG to settle, the FIPG needed 24 hours to set. Ran the car up today with no issues and no differences in its running behaviour so I figure that it will probably still fail emissions. I'll get it in after the bank holiday to confirm.
My only other thought is to swap the Denso lambda for a genuine Toyota one as everything else appears fine.
I'll report back with more updates once I know how it stands on the testing front.
MJ
pompeymj said:
1. I've been told the vehicle was previously remapped, surely if it had been then it would already be tuned for optimum settings and therefore would easily pass emission tests.
I'm at a loss of what to check next, I was wondering if the new cat needs some mileage under it to 'break' it in. I am thinking of a remap, could anyone recommend anywhere in the Portsmouth area?
Mike
The stock ECU is not remappable, so unless there's a piggyback or standalone unit in there, it's not been remapped. There are non mappable aftermarket ECU's available from people like TOMs, Mines, Blitz etc, so it might have one of those. They are quite rare on an NA though, much more common on a 3SGTE car. I'm at a loss of what to check next, I was wondering if the new cat needs some mileage under it to 'break' it in. I am thinking of a remap, could anyone recommend anywhere in the Portsmouth area?
Mike
Afternoon all,
I got the car back on the emissions machine today, she passed the CO but still failed lambda. An auto electrician is going to connect her up and see if there are any codes being stored, as was previously suggested, but this won't be until later in the week.
Sonic, I will assume she hasn't been remapped then if that is the case. Thanks for the info.
Mike
I got the car back on the emissions machine today, she passed the CO but still failed lambda. An auto electrician is going to connect her up and see if there are any codes being stored, as was previously suggested, but this won't be until later in the week.
Sonic, I will assume she hasn't been remapped then if that is the case. Thanks for the info.
Mike
pompeymj said:
Afternoon all,
I got the car back on the emissions machine today, she passed the CO but still failed lambda. An auto electrician is going to connect her up and see if there are any codes being stored, as was previously suggested, but this won't be until later in the week.
Sonic, I will assume she hasn't been remapped then if that is the case. Thanks for the info.
Mike
I assume the process for checking codes is the same as the MR2 - all you need is a paper clip to bridge terminals E1 and TE1, and then you count the flashes on the dash. I got the car back on the emissions machine today, she passed the CO but still failed lambda. An auto electrician is going to connect her up and see if there are any codes being stored, as was previously suggested, but this won't be until later in the week.
Sonic, I will assume she hasn't been remapped then if that is the case. Thanks for the info.
Mike
http://www.mr2oc.co.uk/know-your-2-knowledge-base....
That's similar to my Volvo 850, early ones had an onboard flashing light depending on where the flying lead was connected, one connection for engine, one for gearbox etc, mine doesn't have the module so I made my own blinking light box.
If I get a chance later today I'll give this a shot.
Mike
If I get a chance later today I'll give this a shot.
Mike
I didn't get any error codes appearing by using the paper clip method.
Assuming this is the case than is there an argument for a poor join or small crack somewhere in the exhaust, I've not felt or heard one but it's quite difficult laying on the ground and doing it.
Can someone answer this, the exhaust system is a closed loop in terms of lambda:exhaust manifold >> downpipe (which contains the lambda) >> cat (which contains a temperature sensor as its a JDM) >> centre silencer >> rear silencer. A high lambda reading from an exhaust probe is located at the rear silencer, if the system is working correctly and self adjusting then a lean reading (high lambda) would indicate a leak somewhere after the cars lambda sensor but before the end of the exhaust (obviously) - is this assumption correct? A poor joint or crack before the cars lambda would surely be rectified by the ECU making the car run richer or is this all false logic?
I'm planning on pulling the system apart, rejoin every junction, but if I can get away with just the rear half as per my logic above then I'll be happier.
Assuming this is the case than is there an argument for a poor join or small crack somewhere in the exhaust, I've not felt or heard one but it's quite difficult laying on the ground and doing it.
Can someone answer this, the exhaust system is a closed loop in terms of lambda:exhaust manifold >> downpipe (which contains the lambda) >> cat (which contains a temperature sensor as its a JDM) >> centre silencer >> rear silencer. A high lambda reading from an exhaust probe is located at the rear silencer, if the system is working correctly and self adjusting then a lean reading (high lambda) would indicate a leak somewhere after the cars lambda sensor but before the end of the exhaust (obviously) - is this assumption correct? A poor joint or crack before the cars lambda would surely be rectified by the ECU making the car run richer or is this all false logic?
I'm planning on pulling the system apart, rejoin every junction, but if I can get away with just the rear half as per my logic above then I'll be happier.
pompeymj said:
I didn't get any error codes appearing by using the paper clip method.
Assuming this is the case than is there an argument for a poor join or small crack somewhere in the exhaust, I've not felt or heard one but it's quite difficult laying on the ground and doing it.
Can someone answer this, the exhaust system is a closed loop in terms of lambda:exhaust manifold >> downpipe (which contains the lambda) >> cat (which contains a temperature sensor as its a JDM) >> centre silencer >> rear silencer. A high lambda reading from an exhaust probe is located at the rear silencer, if the system is working correctly and self adjusting then a lean reading (high lambda) would indicate a leak somewhere after the cars lambda sensor but before the end of the exhaust (obviously) - is this assumption correct? A poor joint or crack before the cars lambda would surely be rectified by the ECU making the car run richer or is this all false logic?
I'm planning on pulling the system apart, rejoin every junction, but if I can get away with just the rear half as per my logic above then I'll be happier.
IIRC, the cat temperature sensor only serves to operate the cat temperature warning light on the MR2, so I would think it would be the same on the Celica as the engine is the same - it doesn't affect the the car at all. Assuming your lambda sensor is functioning correctly, then yes, I think that's a fair assumption based on the info you have. Assuming this is the case than is there an argument for a poor join or small crack somewhere in the exhaust, I've not felt or heard one but it's quite difficult laying on the ground and doing it.
Can someone answer this, the exhaust system is a closed loop in terms of lambda:exhaust manifold >> downpipe (which contains the lambda) >> cat (which contains a temperature sensor as its a JDM) >> centre silencer >> rear silencer. A high lambda reading from an exhaust probe is located at the rear silencer, if the system is working correctly and self adjusting then a lean reading (high lambda) would indicate a leak somewhere after the cars lambda sensor but before the end of the exhaust (obviously) - is this assumption correct? A poor joint or crack before the cars lambda would surely be rectified by the ECU making the car run richer or is this all false logic?
I'm planning on pulling the system apart, rejoin every junction, but if I can get away with just the rear half as per my logic above then I'll be happier.
Evening,
I've popped my head under tonight to verify the condition of the pipe after the cat, generally it looks fine. Tomorrow I'll be fitting new gaskets either side of the cat but I'll definitely clean up all mating faces first. The centre to rear silencer is welded so I can't do much about that.
I'm booked in for another emissions check on Thursday so I'll update then.
I've popped my head under tonight to verify the condition of the pipe after the cat, generally it looks fine. Tomorrow I'll be fitting new gaskets either side of the cat but I'll definitely clean up all mating faces first. The centre to rear silencer is welded so I can't do much about that.
I'm booked in for another emissions check on Thursday so I'll update then.
pompeymj said:
Evening,
I've popped my head under tonight to verify the condition of the pipe after the cat, generally it looks fine. Tomorrow I'll be fitting new gaskets either side of the cat but I'll definitely clean up all mating faces first. The centre to rear silencer is welded so I can't do much about that.
I'm booked in for another emissions check on Thursday so I'll update then.
It is easier to check for leaks, especially small / pinhole type leaks, with the car on a 2-post ramp and the engine running. The MoT station found all the leaks on my MR2 and their body-shop welder welded everything up. I could not be bother to move the car so I thought the easiest way is to give the welder beer money (£20) and get the job some all at once.I've popped my head under tonight to verify the condition of the pipe after the cat, generally it looks fine. Tomorrow I'll be fitting new gaskets either side of the cat but I'll definitely clean up all mating faces first. The centre to rear silencer is welded so I can't do much about that.
I'm booked in for another emissions check on Thursday so I'll update then.
Afternoon all,
Sorry for the lack of updates I haven't been able to post due to being a newbie and lots of crap was going on in the forums.
Anyway, last Thursday I managed to experiment with the Celica's emissions on my friendly MoT guys machine. Eventually we got it to pass but I had to replicate this effort with another tester without my presence. We had discovered that due to the large bore of the tail of my exhaust pipe there wasn't sufficient back pressure, the exhaust sensor on the MoT machines were reading the exhaust and the atmosphere, for our test we stuffed blue roll loosely in the pipe which removed the atmospheric portion and so it passed.
Ideally I would switch the tail for a new, more normal sized one, which I would've done had it not been welded to the centre silencer. The eventual answer was a McGuyver type affair involving a mushy pea tin, the ring off a single camp burner, tinfoil and cotton pads. This formed a restricted flow at the end which was sufficient to pass the test.
The rear and centre silencers will be switched out at some point but for now all is good. Thanks for your comments guys. I'll post a picture of the solution later on.
Michael
Sorry for the lack of updates I haven't been able to post due to being a newbie and lots of crap was going on in the forums.
Anyway, last Thursday I managed to experiment with the Celica's emissions on my friendly MoT guys machine. Eventually we got it to pass but I had to replicate this effort with another tester without my presence. We had discovered that due to the large bore of the tail of my exhaust pipe there wasn't sufficient back pressure, the exhaust sensor on the MoT machines were reading the exhaust and the atmosphere, for our test we stuffed blue roll loosely in the pipe which removed the atmospheric portion and so it passed.
Ideally I would switch the tail for a new, more normal sized one, which I would've done had it not been welded to the centre silencer. The eventual answer was a McGuyver type affair involving a mushy pea tin, the ring off a single camp burner, tinfoil and cotton pads. This formed a restricted flow at the end which was sufficient to pass the test.
The rear and centre silencers will be switched out at some point but for now all is good. Thanks for your comments guys. I'll post a picture of the solution later on.
Michael
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