M.O.T. FAILURE EXHAUST EMMISIONS

[IDI AMIN]

Car failed m.o.t on exhaust emissions so would be grateful for tips on how to sort it list is as follows

Exhaust emissions carbon monoxide content after 2nd fast idle excessive [ 7.3.D.4]
Exhaust emissions hydrocarbon content after 2nd fast idle excessive [ 7.3.D.4]
Exhaust emissions Lambda reading after 2nd fast idle outside specified limits [7.3.D.4]

Fast idle test readings

MAX LIMIT ACTUAL VALUE
CO 0.300 0.459
HC 200 209
LAMBDA 1.030 1.039


SECOND FAST IDLE TEST

CO 0.300 0.455
HC 200 210
LAMBDA 1.030 1.033

I've only listed the readings it failed on hopefully someone can help someone has already suggested injector cleaner so i'm wondering what others suggest. would redex help any . There is a few others on the mot list but i can sort them its just the emissions i need advice on thanks

hope you can understand the list i tried to space it but when posted all readings are together

 

[MikeS]

did you thrash it down the motorway for a good 30 mins before mot ?

 

[IDI AMIN]

No never done that should i do that with some redex in before retest

 

[MikeS]

wont hurt

usual service helps also

give the car a good 30 - 1 hour drive before mot

if it still fails then you need to look at the fueling

 

[IDI AMIN]

I will write again so its easier to understand
Idle test
CO : max limit - 0.300 actual value - 0.459
HC : max limit - 0.200 actual value - 209
Lambda : max limit - 1.030 actual value -1.039

Second fast idle test
CO : max limit - 0.300 actual value - 0.459
HC : max limit - 0.300 actual value - 0.455
Lambda : max limit -1.030 actual value - 1.033

 

[IDI AMIN]

wont hurt

usual service helps also

give the car a good 30 - 1 hour drive before mot

if it still fails then you need to look at the fueling

Maybe a new fuel filter? it got new spark plugs couple of months ago. maybe clean air filter element or a new one i also wire brushed the two sensors on the exhaust at the weekend and gave them a blow out with air to remove carbon build up

 

[IDI AMIN]

natural idle test reading
passed on this one
max limit
0.500

actual value
0.405
if this helps any more info on what to do

 

[Matt]

Have you got any modifications to the exhaust? Sports cat fitted?

 

[astra22bertoneauto]

wont hurt

usual service helps also

give the car a good 30 - 1 hour drive before mot

if it still fails then you need to look at the fueling

As mike said!

 

[IDI AMIN]

No mods done exhaust or air filter or anything like that its just standard as far as i know
does look at fueling mean new fuel filter and some rededx

 

[IDI AMIN]

s**ts getting expensive just now 148.50 on road tax 40 for mot 42 quid on rear discs pads and handbrake shoes need a new tyre also for test new wipers and whatever else to sort emissions all in less than a week think i need a new abs sensor also. will go for a run just now got half a bottle of redex will put it in then get another tomorrow for before the retest. i'll just eat water for dinner for the next couple of weeks

 

[evocarlos]

i'll just eat water for dinner for the next couple of weeks

its better if you freeze the water and suck on it i found it lasts longer and you can save more money lol

i hate to think what ive spent on my astra since last year prolly 3 times the cars value

 

[IDI AMIN]

Its crazy what we spend on cars the big killer for me is its all at once

 

[evocarlos]

i meant to add did you check for leaks in the system
i had one of my old cars fail the mot on emissions due to a bent flange and it was causing high readings had to beat it with a big hammer to make it flat then gungum it up it passed after that
may be worth just checking my astra weeps out the center joint always has once its warm it seals up but drips water when its cold out the joint

 

[IDI AMIN]

yeah its possible i'll give it a check tomorrow meant to do that last saturday when i cleaned the exhaust sensors you wouldnt happen to know the size of bolts that hold the middle pipe to manifold would you i had replacements on it a while back but they were the wrong size to thin and too long was all i had available at the time the old ones were worn and the heads too big .im guessing about m8 or m10

 

[jwalker]

They're M8 but not sure of the length

 

[IDI AMIN]

cheers for that the ones on just now are a bit rusty

 

[evocarlos]

edit - i was to late in reply lol
looking at a pic of the flange i would say m10 but maybe someone else can confirm if there m8 or m10
ive never touched that flange on mine in all the time ive had it so not much help sorry

 

[jwalker]

M8 for the bolts joining the centre section to the downpipe, the bolts above are part of the manifold and not listed as a separate part. If you think that's a problem then maybe check the gasket

 

[IDI AMIN]

Sorry not they ones carlos and j walker i meant middle pipe to cat section i done the ones pictured when i changed manifold when i done cylinder head work the newer one i got had one of the studs missing.