MOT Probs - Fast Idle Test

[m888arc]

my cars failed on the CO% volume ..... it should be reading at about 0.30 or around it..... but mines reading at 0.50+.

according to my mechanic my car is running to rich.....DO YOU THINK it may have something to do with my has be running de-cat for best part of 6months, and i put that cat on yesterday hoping it would pass???

bcoz, doesnt the ECU kinda reset itself after a while, and with the cat just being put on, it wouldnt have had time to reset??

btw..... i dont think it has a PBV , as my mechanic asked me, coz we could just adjust the fuel/air ratio.

ANYHELP is appriated, thanx, Marc.

 

[m888arc]

**update**

just been out and started it up, its pretty cold here so i woz hoping to see ne fumes coming from around the cat or the joins......but nope, sealed tight. so there isnt a problem with when the cat got refitted.

also disconnected the battery (both - and +) hoping it will reset the ECU, and will leave it disconnected for a few hours while i go to uni.

ANYONE ELSE THINK OF WHAT IT MIGHT BE???

Thanx, Marc.

 

[Matbrown]

Take it for a good drive down the motorway and get the cat warmed up then take it for the test while its nice and toasty...

If it still fails it might be knackered, either that or your Lambda sensor is up the swanny.



Mat.

 

[BRUN]

euro car parts sell a lambda sensor tester mate, might be worth havin a look at that...

 

[m888arc]

according to the print out the lambda sensor passed the test?!

any other ideas people?

Marc.

 

[BRUN]

how did they test the lambda ?

 

[Just Bob]

The lambda sensor is NOT tested during the MOT.

What you see on the sheet is the Lambda reading. This should read between 0.97 - 1.030. If the reading is between these figures it passes. You say the CO is .50+ - this would more than likely be the Lambda sensor at fault on your car as you have fitted a "new?" cat!

The lambda reading is reached via a calculation of all the gasses emmitted by the exhaust. An engine running perfectly will read1.0.

Hope that helps.

Bob RTE

 

[m888arc]

print out as follow.......

1st fast idle test

CO% Vol - 0.73 - Fail
HC ppm VOL - 62 - Pass
Lambda - 1.02 - Pass

2nd fast idle test

CO% Vol - 0.42 - Fail
HC ppm VOL - 46 - Pass
Lambda - 1.02 - Pass

--------------------------------
Does this show nethign to anyone???

car is going in 2mos mornning for a retest and work to be done by the garage, just i will be paying them £££ an hour labour to find the problem, so its easier if i just surgest what it might be.

Thanx, Marc.

 

[BRUN]

thrash it within an inch of its life before it goes in

and did you stick your hand around the joins mate on the cat......you cant just look cos it might be comin out of the top...

 

[Just Bob]

Brun maybe right about giving it a good thrash before you take it in for a retest. A cat only works when its up to temperature, but with a high CO reading and all the other figures correct, I reckon its still the Lambda sensor, providing the cat you fitted is sound.

Bob RTE

 

[m888arc]

Well, dropped car off at garage this mornin hopeing they would have it sorted and fine for the Re-test...

the guess wot...... the f**ker fails again on the same thing!!!!! god its f**king me off big time. theres absolutly nothin wrong with the car at all..... just f**king emissions.

guy at the garage recommends to add fuel additives over the weekend and clock up as many miles as i can to get the cat settled.

and about getting it warmed up, it wont matter, as i take it to my mates garage who lets it sit around for couple of hours til he can fit it into the mot test center down the road, who is run by some1 else, so he cant fiddle the figures

im well f**ked off, sorry boys....
Marc.

 

[BRUN]

just take it to the test centre urself mate....