what to check first?
New air filter, new plugs. Hc over 300..
Been searching for air leaks, found none..

And the car is a 4wd sapph with cat.

 

Is the car standard mate. If the water temp sensor was faulty that could be giving the wrong readings to the ecu.

 

Is the cat still fitted?

Whats the CO? Why did it fail?

 

Stu:

 

co2 was ok, 0,30

 

Agreed but it may have also failed on CO, so id have looked at lambda etc as well as ignition system, now im looking only at ignition system.

 

Ok, look specifically at poor spark plugs, rotor arm, cap, or maybe just the plugs are gapped too small, or you have champion C57s in.

 

 

my 95 rs2k 4x4 passed without a cat found a friendly mot tester who wanted an extra tenner to pass emissions.

 

I am not a cossie expert but the Hydro-Carbons show if you are burning oil I believe. i know the cossie's use Oil so I would go for an oil change with a good quality oil and see if it helps. Your fuelling is Ok if it passed the CO so don't mess anything to do with fuelling.

Cheers Nick

 

Whoever told you that wasnt an expert either im afraid pal. Hydrocarbons are an indication of the amount of uncombusted feul present in the ehxhaust. (Measured in PPM = Parts Per Million)

Oil can affect the reading of course, but its certainly not what its supposed to indicate.

 

Thanks for your reply, I wasn't trying to give bad advice, I was pointing in another direction.
You say it measures unburnt fuel and I agree, however engine oil is just a few stages away from petrol in the fractional distillation column, all it takes is a lot of heat to turn engine oil into petrol in laymans terms.

Because Engine oil has 3 times the ammount of Hydrocarbons than petrol it would only take a bit of Oil being burnt to mess up the exhaust emissions. granted it needs a high temp to do this but we are talking about internal combustion under pressure.

Its just another way of looking at it but I don't intend to get in a fuss over it

Nick

 

I agree totallay with the fact that burning oil will increase the residual hydrocarbon count in the exhaust gas, what i disagree with is your suggestion that:

As if that was the case, any engine showing other than zero HC's (IE: Pretty much All of them) must be burning oil, which of course they are not. Anyway, lets try and get back on topic as knowning my luck this guys car will be burning oil now. ROFLOL.