2011 on. So last of the 169 models and then the new one.From a certain year onward, yes.
2011 on. So last of the 169 models and then the new one.From a certain year onward, yes.
Hi Jock,Looks like it doesn't it Jack? As you'll know I'm sure, so for the benefit of others, a high (greater than 1.00) Lambda reading means there is excess free oxygen going past the upstream sensor so it outputs a voltage high, 1.4 volts is pretty impressive though, The ECU interprets this and drives the mixture rich to try to compensate. Pulling air round a gasket maybe? Can you hear any "puttering" sounds?
I'm still a bit unsure where diagnostics are concerned but I wonder if a MAP sensor could cause this? Either the sensor itself or an air leak affecting the vacuum the sensor is trying to monitor? However I'm less sure about the possibility of this. I'm very interested in MAP sensors just now and it's given me an excuse to buy a wee cheap (ebay) vacuum pump - something I've been trying to justify for years - so I can test them off the vehicle. Lots of other "stuff" you can do with a vacuum pump too. Ok Jock, you've just convinced yourself!
I have never seen a lambda value that high on an mot test.
Does car have an aftermarket exhaust? Something with twin tail pipes?
Can you hear any "puttering" sounds?
Thanks Jack. I'm still getting my head round all this diagnostics stuff. Making progress I think but also a lot to learn still. So every little bit helps!Hi Jock,
On this one the lambda test result of over 1.4 is the MOT emission test equipment calculation , not a voltage reading from the o2sensor of the car.
The car looks like it may be running ok as the co and hc readings are low and a pass on the MOT emmision test.
Normally a high mot lambda reading is due to leaks in the exhaust system allowing oxygen to enter the exhaust flow before the tailpipe sensor of the MOT test device .
I have never seen such a high mot lambda reading as 1.4.
Cheers
Jack
Plug or partially plug the tail pipe with a damp rag ,any exhaust leaks will be very greatly pronounced , don't rev the engine while doing this.So what can i check for now?
Leaks around the CAT? I know the CAT has 2 sensors on it one pre and one post.
A visual/audible inspection of the exhaust or is there anywhere else i need to look at?
Thanks.
Ok most live readings expired.
Did the engine keep running when you blocked tail pipe?Ok, I have a new oxy/lambda sensor and i tried in both the top and bottom positions either side of the CAT. This made no difference.
I also tried the damp rag up the exhaust trick and there is air blowing a little out of the back box on the front side.
As the car warmed up, there was dirty water coming of the front seam.
I carefully put my hand around the back box but could not feel anything but there is a definite sound.
Did the engine keep running when you blocked tail pipe?
That is 100% proof there is a huge hole in exhaust.Yes.
Anyone that can get the car in the air and is not totally blind should be able to find the leak in seconds !A garage with asmoke machine should be able to find any leaks within minutes
Mot emmisions test machine reading over 1.4 not a large leak of air into exhaust?It won't be a huge hole, as you'd hear that particularly as there is only one silencer that does any real silencing, so I suspect the hole is small. However, the exhaust pulses will allow low-pressure zones where air can be pulled in to the system from the outside, so the advice to get the exhaust fixed/changed is good. It does take quite a lot to make an engine stop by plugging the exhaust so I'm not entirely surprised that a damp rag didn't stall it completely, but it does look like it might be pointing you in the right direction.