ClioSport.net

This is a sample guest message. Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

  • Due to ongoing maintenance work some features and functions (including Dark mode!) may be unavailable or visually appear differently.
  • When you purchase through links on our site, we may earn an affiliate commission. Read more here.

Faulty precat lambda sensor?

Car  Megane R26
Just need a bit of advice on my 182!

-Eml is on, diagnostics reads precat O2 sensor

-35 Mpg on long run compared to the 43+ I was getting in my 172 Cup

-Pulls hard to 5k rpm then becomes flat and strained. Noticeably dips in power

-idles fine, no spluttering or misfire

Is my front lambda sensor shagged? I thought it might be a blowing exhaust but that was welded up and sorted.

I am getting a slight whistling noise as the revs climb, just under full throttle.
Car is standard apart from cat back Scorpion exhaust.
 
I recently had a similar problem, and what finally made me change the lambda was mpg dropping from 42 on the motorway to 31.

Changed it at the weekend for a new Bosch unit from europarts and its back up to 42-44 on the motorway.

I paid 51 quid with a mates trade discount but if you put the weekend discount code in you will get it for about 62 quid

Whistle is probably the cat to manifold joint. Get a new one of those from renaultparts direct while your at it!
 
I recently had a similar problem, and what finally made me change the lambda was mpg dropping from 42 on the motorway to 31.

Changed it at the weekend for a new Bosch unit from europarts and its back up to 42-44 on the motorway.

I paid 51 quid with a mates trade discount but if you put the weekend discount code in you will get it for about 62 quid

Whistle is probably the cat to manifold joint. Get a new one of those from renaultparts direct while your at it!

Appreciate the reply, ordered both
 
best way to see is put it on diagnostics and look at the swing of the sensor... if its not swinging to its full range or is biased to one side then sensor may be at fault... lambdas are a common problem though and are fairly easy to replace
 
best way to see is put it on diagnostics and look at the swing of the sensor... if its not swinging to its full range or is biased to one side then sensor may be at fault... lambdas are a common problem though and are fairly easy to replace
OK nice, I'll have this checked tomorrow, ordered a new lambda sensor, will fit this tomorrow
 
Make sure you get some WD40 or something on it before hand. I tried to remove mine last week and neither lambda's would budge. I'm going to get a little blowtorch to apply some heat to try get them shifted.
 
Make sure you get some WD40 or something on it before hand. I tried to remove mine last week and neither lambda's would budge. I'm going to get a little blowtorch to apply some heat to try get them shifted.

I'll take it to my friendly neighborhood mechanic, he'll have to battle it out with the lambda sensor.
 
Back
Top