Gonna try and wing the NCT.

Phoole

I have mt NCT re-test tomorrow. I know I'm gonna fail it on the Lambda reading. But you never know in this country.

But here's my question to the experts. Is it better to have a warm engine or cold engine when testing the Lambda? Considering the car previously passed the Lambda reading when the engine temperature was tested at 79oC, but failed when it was tested at 100oC. Should I try and keep the engine as cold as possible or burn it up and down the motorway a few times before arriving for my test?

Thanks...

crosstownk

Phoole wrote: »

I have mt NCT re-test tomorrow. I know I'm gonna fail it on the Lambda reading. But you never know in this country.

But here's my question to the experts. Is it better to have a warm engine or cold engine when testing the Lambda? Considering the car previously passed the Lambda reading when the engine temperature was tested at 79oC, but failed when it was tested at 100oC. Should I try and keep the engine as cold as possible or burn it up and down the motorway a few times before arriving for my test?

Thanks...

100C sounds slightly on the hot side - low to mid 90s is more the norm. The test should be carried out at normal operating temperature which is determined by the manufacturer.

If you've a problem with the lambda or other emissions controls, you will most certainly fail the NCT. It'd be better to cancel the NCT and have the necessary repairs done. You may even get better fuel consumption once the repairs are complete.

Gerry

lambda is calculated by measuring the oxygen content of the exhaust. One simple thing that will throw the reading off is a leak in the exhaust. This lets extra oxygen in, screws up the reading. So, does your exhaust have leaks? You could try and patch it up if so. One way of finding leaks is to block the tailpipe with a rag when the engine is idling. This should strangle the engine, it should start to cut out. If it makes feck all difference, you've got a decent sized leak, and you if you keep the exhaust blocked, you should be able to figure out where its coming from. Best of luck.

Phoole

I have had the car up at my mechanics for the past two days. He can't find any leaks, but is confident he'll get to the bottom of it. First there was some corrosion around the back box so I replaced it but to no avail. The Lambda reading was still high. Everything else is reading perfect.

I've had the re-test booked since last week, plus they charge you to cancel it anyway, so I may as well just re-take the test and chance my arm. I know I'm gonna fail it but I'll at least get another 28 days to re-test.

So should I scoot up and down the motorway for half an hour before-hand or not???

BrianD3

IIRC from the previous thread your lambda result was too high/lean - so I reckon do the test with the engine as cold as possible. I don't think it wil make much difference though.

Phoole

BrianD3 wrote: »

IIRC from the previous thread your lambda result was too high/lean - so I reckon do the test with the engine as cold as possible. I don't think it wil make much difference though.

I was thinking that. Hopefully it'll be nice and cold out tomorrow morning

dudara

Phoole wrote: »

I have had the car up at my mechanics for the past two days. He can't find any leaks, but is confident he'll get to the bottom of it. First there was some corrosion around the back box so I replaced it but to no avail. The Lambda reading was still high. Everything else is reading perfect.

Have you replaced the Lambda sensor? They do degrade with age. They also get clogged over with dirt.

kikel

Phoole wrote: »

I was thinking that. Hopefully it'll be nice and cold out tomorrow morning

Better go early. Leave it idle for an hour