Disco 2 V8 - What Now?

[Stokey]

I took the Disco for his MOT and sure enough, as expected, and in accordance with the law of sod, my slight intermittent leak of pas fluid from the steering box manifested itself all over MOT Testers bonce....FAIL! It also failed on emissions (lambda reading element) everything else was fine!
Having replaced the Steering box, exhaust and manifold gaskets, I took him for his re-test only for him to fail on CO2 emissions, which yesterday, it passed................I don't understand why my Disco is treating me so badly....in my tiny mind, I am thinking CAT failure as worse case scenario and my wallet will not cope with that. However, being a Disco owner, I am familiar with the concept of straw grasping, any body any ideas? Is it possible to like turn the emissions down via the BCU or something....I really really want my MOT!

Whats worse, my wife is casting an eye over the Disco, similar to the one that Ian McGregor cast over the pits 25 years ago.....I really can't see her allowing further expenditure this month, when the kids have no shoes and we are living on bread and water (joke in case any of you are Child Welfare Hippies)...and in any event, why should emissions matter on a 10 year old V8 Disco!!!!!!!!!Given the amount of pollution coming from the Far East, our very own 'nearly a Chernobyl' nuclear incident the expansion of airports, alien abduction, MP's expenses, the price of petrol (again!) et-al.....Sorry, I am now ranting...Please, somebody help me....................................

[Jon v8]

What were the actual emissions readings ?

[Stokey]

When it failed the first time the readings were reported as

on fast idle test CO was 0.000 HC was 1 and lambda was 1.471

on second fast idle CO was 0.002 HC was 0 and lambda was 1.510

on natural idle CO was 0.000

It only failed on the lambda readings, which upon gasket replacement appears to have cured the problem....

On retest, Lambda readings were all good, CO reading was 2.000................I could not believe it!

[Jimbob292]

You forget to mention the whale hugging,tree loving veggies in your rant, they will LOVE your V8:D

Emissions what are they, when you consider a Trent jet engine can drink up to 230 ltrs a minute I wouldn't worry.

Joking apart have you cleaned out your injectors with any additive, do you have a clean air filter / maf etc, as to help it breath better.

[Stokey]

Had a complete service, with engine flush.......

[Jimbob292]

Have you tried to reset the ECU, by disconnecting the battery?

[Stokey]

No, not yet, what will that do....forgive me, I have'nt a clue! If it works, I will be the happiest man in Cheshire!

[Jimbob292]

On my Disco 1, i disconnected the battery for a couple of minutes, reconnected, and it forces the ECU to restart its settings etc, i.e. relearn

Was the test done with the A/C at all, as you have the throttle idle valve that forces the engine to run faster with the increased load from the A/C compressor.

[Stokey]

On my Disco 1, i disconnected the battery for a couple of minutes, reconnected, and it forces the ECU to restart its settings etc, i.e. relearn

Was the test done with the A/C at all, as you have the throttle idle valve that forces the engine to run faster with the increased load from the A/C compressor.

AH AH! You little beauty, that may very well explain things....it is an unusually barmy day in South Cheshire, 15 degrees! Yes the AC was on......

[Jimbob292]

It causes rocker cover / crankcase fumes to re-enter the main manifold chamber, hence the crazy readings.

Before you take it for a re-test give it a bit of stick to make sure you blow all the clag out.

Hopefully its a job sorted!

[Jon v8]

The Motronic engine management on your DII is a bit more complex than on a 3.9 DI,disconnecting the battery will do little as it will not reset the long term fuel trims,and the Ecu will automatically compensate for the load imposed by the Hevac requesting the A/C clutch to engage.The original readings suggest a post oxygen sensor exhaust leak,but the second lot of Co readings seem more like the engine was not up to temp,or was running open loop because of sensor failure/disconnection etc.
Which "gasket" was replaced ?

[Stokey]

both the inlet manifold and exhaust down pipe gaskets on each side were replaced

[Jon v8]

Ok,if the inlet manifold has been off,check around that all pipes and sensors have been plugged back in correctly,something is causing it to run open loop to get the Co this high.

[Stokey]

Ta-Da! (I think) Jon V8 and guys, thank you all, It seems that I have a problem with my Idle Air Control Valve, I have un plugged it and low and behold, CO emissions were within tolerance....a pass....now I can just plug it back in and choke some hippies with my CO! Actually, being a caring and considerate sort, I will get the problem sorted soonest. Seems an easy job to do.....added to the list. On the plus side....There were no advisories, so I must be doing something right!

Thanks again Chaps,
Ta ta for now!

[Jimbob292]

You might just get away with gently removing it, and cleaning it with some electrical cleaner / brake cleaner, anything that evaporates quickly.