MOT Failure - Emissions - no Lambda Sensor

[AJSGSE1990]

Good morning, finally have the time to crack on with the Elan and dealing with bearings and suspension should be reasonably linear. Also making an ElanScan cable tomorrow. The failures are:

Exhaust monoxide, hydrocarbon, and lambda outside limits at fast idle. Also monoxide at idle.

From the test station the lambda is reporting 0.81 and at 750-1050 RPM CO level is a whopping 9.3% versus a maximum expected 0.5%.

I have driven the car for a few hundred miles hoping for the mystery bearing would worsen so it could be easier to find, so the car has been through a bit of new fuel. I will do the basics today, like clean injectors, check wiring, leaks, etc. The car always has felt a little sluggish for the theoretical weight/power but have no reference as I have not driven anyone else's.

FUNDAMENTAL ISSUES:
1. Car is not equipped with a Lambda sensor
2. Do not possess an exhaust emissions tester

Question at this stage is, install a Lambda first and confirm the MOT test result so I have a baseline, or will data from ElanScan be able to tell me if my combustion is in any way changing as I do works. In my short experience a faulty MAP tends to make the car run really badly, undrivable.

Both MAP and MAT are cheap and will obviously check vacuum hoses, but was just wondering what the collective wisdom is at this stage.

Thank you very much in advance.

[Tuga2112]

first question is

is it a S2 or a SE/NA ?

the older ones have a 3.5 limit as they will be tested on a pre-cat basis.

if its an older one, converting the car to close loop (adding the O2/lambda sensor) is not rocket science, but may require you to add more wires to the car, and a ECU upgrade (Ron can help with that)

if its a newer one. i would be very surprised how the hell is it runing. because the close loop mappings will trigger limp mode when the sensor is not connected and the car is warm.. i found that out in the middle of the motorway 2-3 years ago

[AJSGSE1990]

if its an older one, converting the car to close loop (adding the O2/lambda sensor) is not rocket science, but may require you to add more wires to the car, and a ECU upgrade (Ron can help with that)

It's an SE Turbo with no Lambda, so open loop. To be honest I am very close to go down the MaxxECU route rather than playing around with chips and systems I do not understand. Been scanning all the wiring diagrams and I think it is doable.

The car currently has few "mods" which perplex me but according to the previous owner predate the last MOT. Could the EGR have failed?

I am not interested in power gains really, mostly reliability.

Cheers.

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[alan e]

Did the mot station put the wrong details in and tested for a S2 Elan which as a Lambda sensor fitted.

[AJSGSE1990]

Did the mot station put the wrong details in and tested for a S2 Elan which as a Lambda sensor fitted.

Good point, answer is that it looks that way. An old MOT test from 2001 shows the Max limit at idle for CO is 3.5%, where the current MOT test centre had it at 0.3%. However, the car was running at 7.5%. HC was marked as max 1200 in 2001, current test max was 200ppm. So in theory it would have passed HC but not CO.

Their Lambda reading was 0.81 which is way off.

Thanks,

Andrew.

[Tuga2112]

the ECU upgrade is the easiest part of changing it to close loop.

even if the wires are already in place. removing the blanking plug is a pretty challenging task. (even more when your forced to do it using an open socket... but thats a story for another day)

i dont think i have a video on the ECU bit. but may equally be part of this one.. i honestly cant remmebr

again to the topic of emissions.
injectors being stuck open can happen, also having the ingition timing wrong can affect the emissions. and you have the CO pot that you can adjust as well https://wikilec.com/view/CO_pot

also that first picture. with the boost solenoid not plugged.. i mean if thats just as the picture. it will be a vacum leak. which will make it rev high on idle and i wouldnt be surprised if that was the cause for the high emissions

another thing to check is if theres a leak in the exhaust. because that can cause the readings to go off as the back pressure is not as high as the reader would expect

[AJSGSE1990]

the ECU upgrade is the easiest part of changing it to close loop.
also that first picture. with the boost solenoid not plugged.. i mean if thats just as the picture. it will be a vacum leak. which will make it rev high on idle and I wouldnt be surprised if that was the cause for the high emissions

Thank you. The exhaust has some evidence of leaking, and the boost solenoid was not plugged in when I bought it a few months back. I managed to release the bolt for the Lambda sensor so at least that worked!

To be honest, on my two Lancias and one Alfa, all pre 1992, I installed Motec and they have been almost 100% reliable (from the electronics side) ever since. MaxxECU are the new contenders for the "street" cars and the expense of getting a new loom made up may outweigh hours and hours looking for an issue.

I might go and buy some scratch cards and if I win get the car an electronic throttle body. In fact I might go and measure up....hmmm...if I get lucky its the same as some random japanese shopping trolley.

The car feels a little strangled and certainly not what I would expect from the power/weight ratio but I have no reference so I could be wrong.

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[Tuga2112]

a complete harness change for the sake of not opening a box and plugging a slot. seems pretty excessive.

look up details about installing the ecu upgrade. its a trivial task for someone who managed to get the clam shell out... i would know.. i done it twice (the clam shell... and the ecu upgrade as well)

[AJSGSE1990]

a complete harness change for the sake of not opening a box and plugging a slot. seems pretty excessive.

Ahahaha...yes that would be logical....instead I just bought a BMW E46 62mm electronic throttle off eBay for £22!