Engine 850: B5234TR/2.3/20v/T5R: - Emissions - MOT Failure

Harvey1963 · Jul 25th, 2019, 20:11

My 1995 T5R has failed it's MOT due to the emissions being all to hell. Very fuel rich apparently.

I've checked hoses for air leaks, and replaced the Idle Control Valve with a new Volvo/Bosch unit as it was definitely faulty and I have run some CAT cleaner through the fuel system and also cleaned the MAF sensor (carefully!).

The emissions have greatly improved but still not enough to pass the MOT. About to go down the road of checking Lambda sensor / CAT replacement. Before I do this does anyone have any other suggestions or experience as to what else to check out?

Until the fail, I hadn't noticed that the Lambda warning light on the dash had a blown bulb. I have replaced this and on start up the the bulb stayed lit. I've cleared the codes which related only to the Idle Control Valve and now it goes out at start up despite there still being a problem with emissions.

volvo again · Jul 26th, 2019, 08:35

I would think it's a failed O2 sensor...

Harvey1963 · Jul 26th, 2019, 12:37

Thanks , heading in that direction.

Jul 25th, 2019, 20:11	#1
Harvey1963 Member Last Online: Dec 15th, 2023 15:35 Join Date: Dec 2015 Location: Montrose	Emissions - MOT Failure My 1995 T5R has failed it's MOT due to the emissions being all to hell. Very fuel rich apparently. I've checked hoses for air leaks, and replaced the Idle Control Valve with a new Volvo/Bosch unit as it was definitely faulty and I have run some CAT cleaner through the fuel system and also cleaned the MAF sensor (carefully!). The emissions have greatly improved but still not enough to pass the MOT. About to go down the road of checking Lambda sensor / CAT replacement. Before I do this does anyone have any other suggestions or experience as to what else to check out? Until the fail, I hadn't noticed that the Lambda warning light on the dash had a blown bulb. I have replaced this and on start up the the bulb stayed lit. I've cleared the codes which related only to the Idle Control Valve and now it goes out at start up despite there still being a problem with emissions.

Jul 26th, 2019, 08:35	#2
volvo again Master Member Last Online: Yesterday 11:03 Join Date: Jun 2018 Location: Presteigne, mid Wales	I would think it's a failed O2 sensor...

Jul 26th, 2019, 12:37	#3
Harvey1963 Member Last Online: Dec 15th, 2023 15:35 Join Date: Dec 2015 Location: Montrose	Thanks , heading in that direction.

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