daniel4781 Posted May 8, 2015 Share Posted May 8, 2015 (edited) Hi boyz. Just went to do get my MOT done, and i got rejected cause i had a high lambda value 1.25 (ref: 1.0 +/- .03). This suggests lean mixture? (or is it the other way around?) (Swedish MOT..) Now i'm down to plausible errors, no error codes as of yet except 3'rd o2 sensor not being connected. "Recently" swapped the o2 sensors, however 3'rd behind cat is not connected, voltage still fine. TB might need a recal not quite sure tho, will probably do anyway. Need to check MAF? (air flow) sensor Might need to check the fuel pressure, filter and the related stuff. Not quite sure if the o2 sensor behind the cat does anything useful, please correct me? if so is there any dummy i can plug in? Anything else i should be checking off while i'm at it? :sidenote: Have also been having rough idle, been hesitating when the acceleration pedal has been slightly pushed or been at the same position for a while. (TB related?) Thanks a lot. :-) Cheers Edited May 8, 2015 by daniel4781 typo's. ;-) (see edit history) Quote Link to comment Share on other sites More sharing options...
Morpheus Posted May 8, 2015 Share Posted May 8, 2015 This may help? http://mechanics.stackexchange.com/questions/7726/failed-emissions-high-lambda-low-hc-and-co Quote Link to comment Share on other sites More sharing options...
Morpheus Posted May 8, 2015 Share Posted May 8, 2015 (edited) The general consensus seems to be an exhaust leak or faulty lambda sensor. Presumably all three sensors are fitted and if so it might be an idea to connect all three as well? http://forums.motester.co.uk/forum3/896.html Edited May 8, 2015 by Morpheus (see edit history) Quote Link to comment Share on other sites More sharing options...
Morpheus Posted May 8, 2015 Share Posted May 8, 2015 (edited) See post 143 here also. Sounds a similar case. http://www.mkivsupra.net/vbb/showthread.php?214650-MOT-questions-and-queries-answered If you have no luck reading up then repost your problem in the above thread and more members will see it if they're subscribed and receive notifications. The best time to post is about 7-8pm for the most replies generally. Good luck! Edited May 8, 2015 by Morpheus (see edit history) Quote Link to comment Share on other sites More sharing options...
daniel4781 Posted May 9, 2015 Author Share Posted May 9, 2015 See post 143 here also. Sounds a similar case. http://www.mkivsupra.net/vbb/showthread.php?214650-MOT-questions-and-queries-answered If you have no luck reading up then repost your problem in the above thread and more members will see it if they're subscribed and receive notifications. The best time to post is about 7-8pm for the most replies generally. Good luck! Hi. No holes in the exhaust and i know the o2 sensors are working. Just want some help as to what parts/systems I need to check for faults and/or what experience others have had with a similar problem. [emoji3] Thanks :-) Quote Link to comment Share on other sites More sharing options...
Nic Posted May 9, 2015 Share Posted May 9, 2015 Not quite sure if the o2 sensor behind the cat does anything useful, please correct me? if so is there any dummy i can plug in? The 3rd sensor is the cat temperature sensor, it illuminates the cat warning light on the dash and has no effect on performance, they normally get removed or cable tied out of the way when decat pipes are fitted. Have you checked the ECU for stored fault codes? Quote Link to comment Share on other sites More sharing options...
daniel4781 Posted May 10, 2015 Author Share Posted May 10, 2015 Will check, however nothing they mentioned when i was there. :S Just ordered a obd dongle, so i will check it when i get it later. Quote Link to comment Share on other sites More sharing options...
daniel4781 Posted May 11, 2015 Author Share Posted May 11, 2015 Hi Just checked and the codes stored was: 24 and 42. Not sure what is up with 42, might be something in the odometer. Will need to check 24 tho, any idea? Quote Link to comment Share on other sites More sharing options...
daniel4781 Posted June 13, 2015 Author Share Posted June 13, 2015 Gonna bump this,. Still a bit off when it comes to 24. It says: Intake Air Temp. Sensor Signal. However i can't find it. :O However i do have the Air Flow sensor. But i can't find any wires to the "Intake Air temp sensor". Did an oil/filter swap, and unbolted most of the intake. Calibrated the TPS, cleaned it all up. I still have occasional fluctuating rpm during warm idle, not quite sure if that is normal?.? If i recall correctly the ECU pretends the air is 20°C when IAT is not working, so it shouldn't change the lambda value to much? or am i wrong? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.