850 T5 Running badly & lambda light on.

[cammy33]

Over the weekend my T5 has started misfiring & running poorly the lamda light has also come on. I have checked the basic stuff like plugs & rotor arm. Also cant find any leaks around the induction. It is idling poorly aswell & seems to be over fueling. Any info would be great or things I can check before I send it to the garage, the car has been faultless untill now.

[cammy33]

I did try unplugging the o2 probe, and the car runs exactly the same so could be worth a try? Where is best to purchase one? are the universal probes anygood?

[Rockatansky]

You need to get the codes read rather than swapping random parts.

Where are you located?

[cammy33]

I am in North Lanarksire- Scotland. Thanks.

[Rockatansky]

If you happen to find yourself near Edinburgh then I can read the codes for you.

[cammy33]

Thanks thats a very kind offer. I am not sure it would be good to drive it to Edinburgh. I have booked it in at a local garage on Thurs just to have the codes read. Hope it's not anything major.

[irf]

Sounds like a boost leak. Dunno which t5 you have but common places on the 850 t5 for a boost leak are the elbows under the fuel rail or the one under the power steering resovoir which is hard to find if you don't know where to look.

Also, check all the intercooler piping very carefully.

Edit. Duh, says 850 in the title lol.

Edited by irf on Tuesday 31st July 20:20

[cammy33]

Thanks it's a 1996, not sure about a boost leak because it will still pull well up to the limiter, but lower down its coughing n spluttering, around 2000-3000 rpm is the worse part of the range, also the idle is very rough, sometimes cutting out.

[Skellen]

My bet is front 02 sensor or MAF - and my money is on the later.

[Pothole]

Could also be a temp sender. My S90 showed the same symptoms. Does the fan come on randomly?

[cammy33]

I got the codes read today & the MAF was at fault. I have replaced it with a new part & car is running well but the idle speed is slightly high just about 1000rpm.

[cammy33]

I think it is now sorted, I cleaned out the idle control valve. It now idles just under 1000rpm, but the new MAF has defo released some missing BHP, in the wet it will now spin the wheels in 3rd!

[morgrp]

Is it the cam sensor gone? - very common on 800 series - later fixed on the V/S models