Hi all
Just been presented with the emissions sheet for my tin-top and it doesn't look good. There seems to be a distinct pattern of failure but I've no experience in the "what causes what" of emissions.

Here's what they came up with:

Fast idle petrol + catalyst
Run1
RPM: 2755
CO: 4.63 (allowed 0.3)
HC: 157 (allowed 200)
Lambda: 0.878 (allowed 0.95-1.09)

Run2
RPM: 2583
CO: 4.43 (allowed 0.3)
HC: 149 (allowed 200)
Lambda: 0.881 (allowed 0.95-1.09)

Please can someone point me in the right direction? Don't be afraid to point out the obvious!

Cheers
Steve

running too rich,what car is it?

quote:

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Originally posted by theconrodkid
running too rich,what car is it?

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check the simple things first,is engine getting hot enough,check temp sensor (ohms meter reqd),air filter and lambda sensor

Leak on the air flow meter ?
Its a common problem , but dont know more than that????

well your lamda sensor
hc passed no probs
so all you have to worry about is your CO reading !

first start of with some fuel injector cleaner, air filter,try to remove your lamda sensor and clean it, (spray it with carb cleaner), also check to make sure your exhaust isnt blowing any where!
even the tinyist wisper will make your CO level high,
if that fails then would consider changing the cat converter (last choice!)
but do check for any small leak in the exhaust system

take it for a good run (thrash it a little and try to hold the revs up in each gear to get the cat warm) 5 to 10 miles if poss !
then try the emmision test again

hope that helps
cheers paul
p.s keep us informed of the results

[Edited on 13/10/05 by ch1ll1]

[Edited on 13/10/05 by ch1ll1]

Cheers for the pointers guys!

Will have a good check of everything you've mentioned in the morning! Too dark now

Even though I haven't found the cause, having a few pointers from the forum is enough to guarantee a more peaceful nights sleep

Luckily my Locost is "visible smoke only"
but then again...If it wasn't I may have learnt a little about emissions!

Cheers all
Steve

Check your plugs to see if you have fouling in a cylinder or two, or if the problem is generalized. A local problem will most likely be ignition.

How's the engine run?

Lambda sensor -- they get slow with age nothing youcan do to put it right but this might not be the problem.

Discovery MPi thats the 134 bhp 2 litre T16 from the Rover 820Sli with a Rover-Motorola Mems ECU.

The engine is running very rich so my first suspect would be the coolant temperature sensor, it could also be an ECU earth problem Rover cars of the period were prone the main earth point for the ECU not giving a good earth.

However with these early MEMS ECU the MAP sensor is mounted within the ECU and conected by a long capilary tube --- first thing to do is very carefully (nb the pipe fitting on the ECU is fragile and gets more brittle with age) remove the tube at both ends and blow it through -- often the vapour trap i the pipe will be full of fuel and gunge.


Next check the Lambda sensor heating element is working --- and put a digital voltmeter or better oscilloscope on the signal wires to see if the are rapidly "switching" up and down the voltage range.

Note if you do decide to replace the Lambda probe it has to be the correct 4-wire Zirconia oxygen sensor type see

http://www.gendan.co.uk/oxygen_sensors.php?manufacturer=Land%20Rover

Also because Land-Rover sold to the US market your Disco might have a standard OBD2 ISO2 connector for diagnostics.

[Edited on 13/10/05 by britishtrident]

" Well your lambda sensor passed " . Afraid not , should be between 0.95 and 1.09 . 0.881 is well out . Check items already suggested starting with the simple/cheap ones. Best of luck

PLEASE TAKE NOTICE OF THE LAST SECTION
Basic fault finding for advanced emission test failures:

If a vehicle fails for high CO at idle and /or fast idle then.... if Lambda is too low, the mixture is too rich. This can be caused either by a misfire or by a faulty Lambda sensor. If it's running very rich, the 02 and HC will be higher than normal.
if it has a high Lambda and high 02 (0.5 to 1.5%), the "CAT" could be faulty. Before condemning it make sure its hot enough to work, the Lambda and other sensors are working OK and the exhaust downpipe hasn't got any leaks.
if the vehicle fails for high HC then ...if the CO passes, the vehicle is probably misfiring. Or if the CO fails and the Lambda reading is too low, the mixture is probably too rich and it may also be misfiring.
if the CO fails, the Lambda reading is high and the O2 reading is high (0.5 to 1.5%) the "CAT" could be faulty. Again check out the simple measures above before condemning it.
if the Lambda fails then...if its too high the Lambda sensor may be faulty, the mixture may be too weak or there may be a hole in the exhaust downpipe. If Lambda is too low the sensor may be faulty, the mixture may be rich or the vehicle may be misfiring.
alittle

[Edited on 13/10/05 by ch1ll1]

[Edited on 13/10/05 by ch1ll1]

[Edited on 13/10/05 by ch1ll1]

All pointers duly noted...thanks to all

The level of knowledge (and the detail!) on the forum never ceases to amaze!

Just been informed I'm working away from home till feb, so I'm going to SORN it and sort out the emissions next year. There was a few more failure points that, although the parts are very cheap, I just don't have time now to do the work.

At least I'll have time to spam up on the subject.

Once again, many thanks

Steve

quote:

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Originally posted by big_wasa
Leak on the air flow meter ?
Its a common problem , but dont know more than that????

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One thing I forgot to mention was the thermostat --- they get "colder" with age stick in a new 88c degree one -- Halfrauds will try to sell you an 83 but should be an 88c same type as the Mini, Ford Xflow