Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: downsmen on 19 September 2009, 15:52:28

Title: Failed MOT
Post by: downsmen on 19 September 2009, 15:52:28
Hi just got back from MOT, bad news it failed on Emmisions.

Here are the readings i got.

Fast Idle
CO 0.76            Fail
HC 97               Pass
Lambda 1.03     Pass

2nd Fast Idle

CO 0.80            Fail
HC 97               Pass
Lambda 1.03     Pass

If any one has ideas how to fix this i would be greatfull

Cheers
Paul
Title: Re: Failed MOT
Post by: rustym95 on 19 September 2009, 16:46:36
Sounds like u have the same problm as other member, try, mgetting a new air intake sesore, little one in front of the MAF see if it reads on a meter 0.08 oms or 0.10 oms if higher number its on its way out. check it first, if it has gone first before checking out other faults, have u done the paper clip test, do that see wha numbers comes up or not.
Try 1  these http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170376231488&ssPageName=STRK:MEBDIX:IT :y
Title: Re: Failed MOT
Post by: JayMV6 on 19 September 2009, 20:46:28
do them risitors actully work?
Title: Re: Failed MOT
Post by: rustym95 on 19 September 2009, 21:02:48
Yes I have 1 it just fools the ECU to think its at a higher climate, no slow take off, fuel consumption lowerd, was 25miles to gal now im 35miles to gal, + just changed timing belt so should be more now, but im not of out in her till wed as getting new ecu (revamp Voxecosport), but it is realy good should put your emmisions down, just on safe side check the flex pipe on exhaust they like to brake off had to weld mine back on they dont flex well.
Title: Re: Failed MOT
Post by: downsmen on 20 September 2009, 18:17:55
Hi whilst looking at the car earlier i noticed there was only 3 bolts holding the exhaust to the manifold, have now put all four bolts back in and put some gum gum on the gasket.
Could this have been the problem for the CO reading causing it to fail. :-/

Title: Re: Failed MOT
Post by: KillerWatt on 20 September 2009, 19:51:00
Quote
Hi whilst looking at the car earlier i noticed there was only 3 bolts holding the exhaust to the manifold, have now put all four bolts back in and put some gum gum on the gasket.
Could this have been the problem for the CO reading causing it to fail. :-/

No.
The CO reading is how much carbon monoxide is being emitted, for whatever reason your car is running too rich on the fuel/air mixture.

First thing I'd do before spending any money is take a look at the air filter.
Title: Re: Failed MOT
Post by: Andy H on 20 September 2009, 19:59:11
Quote
Hi whilst looking at the car earlier i noticed there was only 3 bolts holding the exhaust to the manifold, have now put all four bolts back in and put some gum gum on the gasket.
Could this have been the problem for the CO reading causing it to fail. :-/

Or on the other hand....
If air was being drawn in to the exhaust it would increase the quantity of oxygen in the exhaust & fool the lambda sensor in to reporting that the engine was running lean. The ECU would then alter the fuel trim to chuck more fuel in.

Once you have fixed any obvious faults (such as leaking manifolds and blocked air filters) you will save yourself a lot of wasted time if you can get someone who has Tech2 (and the skills to use it) to read the live values and fuel trims.
Title: Re: Failed MOT
Post by: KillerWatt on 20 September 2009, 20:08:29
Quote
Quote
Hi whilst looking at the car earlier i noticed there was only 3 bolts holding the exhaust to the manifold, have now put all four bolts back in and put some gum gum on the gasket.
Could this have been the problem for the CO reading causing it to fail. :-/

Or on the other hand....
If air was being drawn in to the exhaust it would increase the quantity of oxygen in the exhaust & fool the lambda sensor in to reporting that the engine was running lean. The ECU would then alter the fuel trim to chuck more fuel in.
Ignoring the fact that the exhaust blows gases out rather than sucking them in, the manifold would have to all but be hanging off the head to cause the lambda to think there isn't enough oxygen.
Title: Re: Failed MOT
Post by: Abiton on 21 September 2009, 08:46:30
Bump for some expert attention.  Apart from Andy H, there seems to be a lot of dodgy information/advice being offered here.
Title: Re: Failed MOT
Post by: Andy B on 21 September 2009, 08:56:29
Quote
......
Ignoring the fact that the exhaust blows gases out rather than sucking them in, the manifold would have to all but be hanging off the head to cause the lambda to think there isn't enough oxygen.

A pin hole in the exhaust further back can have quite a significant effect on the lambda readings .....  a well placed lump of Gum Gum can mean the difference between a pass & a fail - well it has for me.  :y
Title: Re: Failed MOT
Post by: KillerWatt on 21 September 2009, 09:12:33
Quote
Bump for some expert attention.  Apart from Andy H, there seems to be a lot of dodgy information/advice being offered here.
Other than what you have just written, I see no other input from yourself as to where the OP should start looking first.

Title: Re: Failed MOT
Post by: Andy H on 21 September 2009, 11:05:41
Tech 2 services available from http://theboy.omegaowners.com/tech2/prices.shtml

Or something like "My Naff Code Reader" can give you live readings if you like to do everything yourself http://www.omegaowners.com/forum/YaBB.pl?num=1236032406