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4x4menow Articulating
Joined: 02 Apr 2004 Odometer: 553 Location: stroud
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Posted: Tue Dec 15, 2009 9:18 pm Post subject: emisions too high
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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
Thanks Nick
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excossack Mud Obsessed
Joined: 06 Mar 2005 Odometer: 2903 Location: Somewhere
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Posted: Tue Dec 15, 2009 10:18 pm Post subject:
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Service, new filters, injection cleaner and take it for a good run before hand so its nice and warm.
__________________________________ Thanks - John |
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terence Guest
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Posted: Wed Dec 16, 2009 12:21 am Post subject:
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check the obvious , like lambda sensor, air mass , run 0.5% methanol in it.
after a good service as others have suggested..
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Ray_Jnr Banned!
Joined: 06 Mar 2006 Odometer: 4671 Location: The Northeast
1987 Land Rover 90 TD
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Posted: Wed Dec 16, 2009 2:36 am Post subject:
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^^^ now thats a comprehensive answer.
come on dennis
__________________________________ Founder of the Difflock Ginger Goatee Club! |
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4x4menow Articulating
Joined: 02 Apr 2004 Odometer: 553 Location: stroud
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Posted: Wed Dec 16, 2009 6:21 pm Post subject:
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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
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Rossko Articulating
Joined: 23 Jan 2007 Odometer: 757
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Posted: Thu Dec 17, 2009 9:06 am Post subject:
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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.
__________________________________ www.glass-uk.org |
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4x4menow Articulating
Joined: 02 Apr 2004 Odometer: 553 Location: stroud
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Posted: Thu Dec 17, 2009 7:59 pm Post subject:
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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 but i dont know how (or how much £££ )
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
Nick
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excossack Mud Obsessed
Joined: 06 Mar 2005 Odometer: 2903 Location: Somewhere
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Posted: Fri Dec 18, 2009 8:20 am Post subject:
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What colour are the spark plugs? Black - Overfuelling.
__________________________________ Thanks - John |
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blanche_90 Mud Obsessed
Joined: 23 Nov 2004 Odometer: 2515 Location: recession land
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Posted: Sun Dec 20, 2009 10:49 am Post subject:
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yep!
go on dennis, bung em up, your post are always a good read.
__________________________________ politicans are like a baby's nappy, they need changing often for the same reason |
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excossack Mud Obsessed
Joined: 06 Mar 2005 Odometer: 2903 Location: Somewhere
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Posted: Mon Dec 21, 2009 4:02 pm Post subject:
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Faulty sensor, split vacuum hose/MAP sensor hose.
Timing a tooth out ?
__________________________________ Thanks - John |
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Rossko Articulating
Joined: 23 Jan 2007 Odometer: 757
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Posted: Tue Dec 22, 2009 7:42 am Post subject:
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lindenengineering wrote: | .. with new plugs, wires, filters etc. |
Couple of odd-numbered plug leads crossed over?? ("It drives fine" often gets reported even with only six cyls!)
__________________________________ www.glass-uk.org |
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jamie_grieve Articulating
Joined: 19 Aug 2009 Odometer: 876 Location: South Scotland
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Posted: Wed Dec 23, 2009 1:25 am Post subject:
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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?
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jamie_grieve Articulating
Joined: 19 Aug 2009 Odometer: 876 Location: South Scotland
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Posted: Wed Dec 23, 2009 2:26 am Post subject:
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I think I'd need to go back to school if I had a scanner
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?
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Rossko Articulating
Joined: 23 Jan 2007 Odometer: 757
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Posted: Wed Dec 23, 2009 9:58 am Post subject:
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jamie_grieve wrote: | 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? |
The bank's fuelling trims are independantly managed.
I find it helpful to remember what the sensors do ; they are indeed Oxygen sensors, not mixture sensors. Can cause complex interactions...
For an ignition misfire (duff lead) for an unrelated example, unburnt mixture enters the exhaust. The sensor detects oxygen, the engine ECU misinterprets that as meaning "lean" and cranks up the fuel trim on that bank. Now we have one cylindering misfiring due to an ignition issue and three cylinders running way too rich, maybe rich enough to have mixture-based misfires. Then we get more oxygen in the exhaust and add even more fuel ...
If cats are fitted they will do their best to eat the unburnt fuel/air and probably be glowing red by now ! All from a wonky spark lead.
Just about anything that causes incomplete combustion - wear'n'tear, potato in the exhaust - can start us on the road to rich running which brings its own distracting symptoms.
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jamie_grieve Articulating
Joined: 19 Aug 2009 Odometer: 876 Location: South Scotland
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Posted: Wed Dec 23, 2009 11:10 am Post subject:
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Thanks guys for some really clear answers. makes perfect sense.
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4x4menow Articulating
Joined: 02 Apr 2004 Odometer: 553 Location: stroud
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Posted: Wed Dec 23, 2009 7:16 pm Post subject:
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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
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Oceantreader Off-Road Guru
Joined: 12 Aug 2007 Odometer: 1089 Location: 52:09:35 North, 1:30:32 West
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Posted: Wed Dec 23, 2009 10:17 pm Post subject:
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Dennis,
Not only is that very enlightening to us lay folk, but you explain it very clearly. Thanks mate.
Mike
__________________________________ RRC bobtail.... metal box on wheels into which you pour money. |
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