MOT fail, emissions out on lambda.

[Joe M 0]

As above, my cars just failed mot on emissions. I expected it as im running a decat but what I did not expect was the lambda to be out as well. Shouldnt that still be ok? Even with a decat?

Im gonnae stick the cat back on tommorow and get it through the retest hopefully, the cat should sort the rest of the emissions but will it affect the lambda at all? It wasnt out by a lot, 0.06 too high I think.

If theres something at fault I take it the most likely would be the lambda sensor as well, im pretty confident most other things should be ok as theres no problems with power.

Good news was there was nothing major it failed on, just an exaust hanger missing and some brake pipes needing secured a bit better. easy fixes. :)

[h100vw 0]

Probe won't be affected by the de-cat. Is this in your rebuilt motor? Has it had some good runs? Wondered if there was maybe a bit of gas in the oil?

Can VRs not be tweaked at all?

Gavin

[Joe M 0]

It is the replacement engine, had some good runs but dunno about gas in the oil?

No easy tweaking on the vr, im just hoping its not my remap being out as it was done on the old engine that had a slightly skimmed cylinder head on it. :?

[h100vw 0]

I was thinking if it were rich maybe a bit of petrol had made it's way into the sump causing it to read rich with the breather connected.

Have you got/can you get a std ECU to swap in?

.

[Joe M 0]

Unfortunately I dont have access to another ecu, plus my vr is a later one with the immobiliser built in so could cause problems.

Ill see how it goes tommorow with the cat on it, might find the downpipe or manifold could have came a bit loose after refitting, though im sure I would have heard that.

If that doesnt work ill give Star P a phone, strangely my 6400rpm limiter seems to have kicked in again so i dont know if its reverted back to the original map or something. (If thats possible.)

[chris g 0]

I had this problem on my last car, Was a Punto GT that i'd just rebuilt the engine. replaced the lamda and gave it a good run before taking it to get it nice and hot and it sailed through.

 

Chris

[Heardy 0]

Joe M Have you got any leaks on the exhaust at all leaks on joints etc can make the lambda reading too high, make sure thereare no leaks.I checked mine at work after i took the cat off and i'm pretty sure it was just the co that it would fail on..

[Joe M 0]

I think that was the problem, the bracket that was missing had meant the exaust was moving about a bit and it was blowing a bit behind the decat. Its now all sealed and resecured properly with the cat back on and I done the brake hoses today so ill put it back in tommorow morning and hopefully all will be good.

[Joe M 0]

Now have mot, emmisions were passed easy with the cat back on.