MOT emissions fail with new CAT fitted

[coullstar 0]

My car failed its MOT last week on emissions but I expected that as no CAT was fitted. I had one fitted today and there is not really that much difference.

The car was converted last year to a 24v and has two lambda's on the downpipe, the other two were deleted.

Its failing on both HC and CO levels. The CO levels are still very high. The car did have a custom code remap and I did think it was running slight rich but Im stumped on what to do next. Maybe a new map which wont be cheap or does it sounds more like one or possibly both lambda's?

 

CO level is 3.71% (0.30%) and HC is 300ppm (200ppm).

[Rustynuts 0]

Does your setup allow you to plug into VAGCOM? If so that might give you the answer. If not it will be a case of suck it and see, changing/testing all sensors will be the only way forward otherwise. Has the conversion been done since the last MOT, if so it might be wise speaking to Custom Code to make sure you have the right map.

[Mawrick 0]

I had a problem with my passat VR6 turned out to be the O2 sensor that caused it, it came up on VAG-COM.

 

I searched around the net to find out if there was any way to "clean" the sensor, and found some info from a manufacturer (can't remember the link), and not 100% sure exactly how it was done but it was similar to doing this:

 

Go out and take the drive for a spin til you get it real hot, then while standing still rev the engine to around 3000 rpm's for around 1 minute......

 

(it's the rpm/time I'm a bit unsure of, but I think it was like this).

 

After I did this and cleared the fault from the ECU I put it in on a new test and it where just fine....:)

 

Just a tip though, have no idea if it will help you.....but it worked for me...;)

[coullstar 0]

Vagcom still works and just by chance I have a friend who did a log a few weeks back. Spoke to him tonight and it looks like the two lambda's after the CAT have not been accouunted for during the remap and they are coming up as open circuit. Therefore the car may have been running on the limp mode since Ive had it. :mad2: This would explain the excessive fuelling that Im seeing and to be honest have seen since Ive had the car. I just thought it was due to the remap. Will phone PSI tomorrow to see what they say. Will not be impressed if they have missed that out. Not good spending all that money and not being able to MOT the car.

 

Hopefully I can get the lamda codes cleared somehow and the car running properly. On the plus side the fitting of the CAT has taken the raspy edge of the exhaust note and its much more subtle.

 

All I would say is that if I was doing it myself I would have run the 4motion dual CATs to run the 4 lambdas.