emisions too high

4x4menow · Posted: Tue Dec 15, 2009 9:18 pm Post subject: emisions too high

P38 went for test today and failed on the emisions being too high 2.35 (from memory as i forgot to pickup the printout)
whats the best way to get them down?
Its a 4ltr v8 P reg
got the heater seals changed and thought all was well but the blend motor isnt working on the drivers side bit cold driveing to the test at 7 am Sad

Thanks Nick

excossack · Posted: Tue Dec 15, 2009 10:18 pm Post subject:

Service, new filters, injection cleaner and take it for a good run before hand so its nice and warm.

terence · Guest

check the obvious , like lambda sensor, air mass , run 0.5% methanol in it.

after a good service as others have suggested..

Ray_Jnr · Posted: Wed Dec 16, 2009 2:36 am Post subject:

^^^ now thats a comprehensive answer.

come on dennis

4x4menow · Posted: Wed Dec 16, 2009 6:21 pm Post subject:

Thanks for the replys
Ive picked up a service kit for it as it needs one because its an insurance write off i dont have any history and dont know when the last one was.
Dennis thanks for your reply was working next to the test centre today and like an idiot forgot to pick up the printout.
will pick it up tomorrow and fit the service kit then i will pick your brains again if thats alright.
Cheers Nick

Rossko · Articulating Joined: 23 Jan 2007 Odometer: 757

As already said, you will need to use an OBD scanner to diagnose this one ; when you do it will probably tell you what is wrong.

4x4menow · Posted: Thu Dec 17, 2009 7:59 pm Post subject:

Well put the service kit on and took it back was a bit better but not a pass
Left it there for the garage to sort out as i havent got a scanner
when i picked it up all was sorted Cool

but i dont know how (or how much £££ Shocked

)
as the mechanic wasnt there only the tester will get the bill tomorow
Thanks for the replys and as its a p38 im sure i will have more questions Laughing

Nick

excossack · Posted: Fri Dec 18, 2009 8:20 am Post subject:

What colour are the spark plugs? Black - Overfuelling.

blanche_90 · Posted: Sun Dec 20, 2009 10:49 am Post subject:

yep!
go on dennis, bung em up, your post are always a good read.

excossack · Posted: Mon Dec 21, 2009 4:02 pm Post subject:

Faulty sensor, split vacuum hose/MAP sensor hose.
Timing a tooth out ?

Rossko · Articulating Joined: 23 Jan 2007 Odometer: 757

jamie_grieve · Posted: Wed Dec 23, 2009 1:25 am Post subject:

My knowledge on petrol engines stops somewhere in the mid 80's before just about everything on your post relates to I'm sure. So I'm looking at the numbers and seeing the HC is like twice the legal limit. I dunno if the cat's supposed to deal with this full time. I doubt it. Is the knackered cat a symptom rather than a cause?
I'm totaly guessing here:
Recon head? Tappet clearance so lifter problem or sticky exhaust valve? Rag in the inlet manifold? Timing belt tooth out as above? Can burning oil give those numbers so some kind of stem seal valve guide thing be happening? I Reckon there's a simple mechanical cause rather than some injector overfueling thing going on. I say that just because I reckon a faulty sensor or something outwith its normal paramaters would shout out about it and would probably have been diagnosed to death but something silly might have been overlooked.
Sooooo?

jamie_grieve · Posted: Wed Dec 23, 2009 2:26 am Post subject:

I think I'd need to go back to school if I had a scanner Embarassed

It's nice to see how a pro approaches it and having the right tools and knowledge to use them really makes life better for everyone. From woah to go how long did it take to diagnose the problem?
I'm a little unclear why the mixture is so rich on the one bank and lean on the other. Does it not always try and maintain lambda 1? I can see a restricted exhaust causing less airflow through the engine, no scavenging taking place and being less efficient. I find it hard to believe it drove OK. Maybe a gradual thing was harder to notice? For talking sake if the car had a carburettor how would that change things?

Rossko · Articulating Joined: 23 Jan 2007 Odometer: 757

jamie_grieve · Posted: Wed Dec 23, 2009 11:10 am Post subject:

Thanks guys for some really clear answers. makes perfect sense.

4x4menow · Posted: Wed Dec 23, 2009 7:16 pm Post subject:

Hi dennis
the garage put some cat cleaner through it and with the service it scraped through its test
they said it was only a temporary fix and it needs checking over to see if anything is playing up will get it checked over after christmas or borrow their scanner and give it a try so i may be asking for help
and it only cost me the price of the test which cant be bad
Thanks Nick

Oceantreader · Posted: Wed Dec 23, 2009 10:17 pm Post subject:

Dennis,

Not only is that very enlightening to us lay folk, but you explain it very clearly. Thanks mate.

Mike