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Discussion Starter #1
Posting on behalf of a mate!!!
He has a RR V8 around 95-96 model, it is EFI.

It started mising a little and became noisey, he noticed the exhaust was coming loose from the manifold, so he put 3 new bolts and new gasket in and it ran fine.

Then it started missing (felt like missing on 1 cylinder only) he was on his way home and it started getting worse, he pulled over and took a look and the RH CAT was glowing Red hot. He stopped the engine and after that it would not start.

Anyone got any ideas???? Thanks from a guy who runs a diesel TD6
 

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The unburnt fuel from the missfire will be burning off in the cat - making it overheat and glow red.Fix the missfire and the cat will stop glowing,leave it too long and the matrix will melt,resulting in higher emissions.
 

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2010-2012 Range Rover MkIII / L322
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Reading the DTC (P-Codes) via the OBD port could directly indicate if a sensor is not working correctly. The best way for you to see it is either via TestBook on the Live Data page, or better still via an Osciliscope such as the PicoScope. You don't need to remove the unit as it can be tested in situ by tapping into the HO2 sensor wires at the input multiplug on the ECU.
 

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2002-2005 Range Rover MkIII / L322
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kins12 said:
Does nobody know how test the oxygen sensors??

Or How can you tell when they are finished
kins12 said:
Could this engine have the CATs removed

How can you test the oxygen sensors

You need to READ the posts already made. You cannot just remove the cats to get around the problem, they will not cause your missfire. As Allyv8 has already said "Fix the missfire and the cat will stop glowing"
 

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Discussion Starter #6
Dan_UK_1984 said:
kins12 said:
Does nobody know how test the oxygen sensors??

Or How can you tell when they are finished
kins12 said:
Could this engine have the CATs removed

How can you test the oxygen sensors

You need to READ the posts already made. You cannot just remove the cats to get around the problem, they will not cause your missfire. As Allyv8 has already said "Fix the missfire and the cat will stop glowing"
The misfire has turned into a non starter, thats why I'm asking on how to test the oxygen sensors. It seems that over fueling is stopping it from starting,
So if I could get it started I might be able to look at the misfire

I have tried searching the posts and could not find out much, hence asking
 

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When you say it is not starting, is it turning over? If so have you checked spark? Have you checked fuel pressure? Since you have read the above posts we can then assume that you have pulled the error codes. Which codes came up? By knowing which codes you have pulled we can better help you. Apologies, but there simply is not enough info here to really give you/your buddy much of a hand.
 

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1995-2002 Range Rover P38A
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now non starting, test crankshaft sensor with a meter set on 20k should give a reading around 1.39
bad crank shaft sensor can and do fail resulting in a misfire then nothing but you may also have other issues too.
 

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Discussion Starter #9
Yes there is spark at the plug, but all plugs are very wet.
There is fuel pressure on the rail.

the wires for the oxygen sensor had melted so to get the sensor out I had to remove the exhaust, will now get another sensor for it.

not sure what error codes are on it, can anyone recommend a OBD scanner that would pull the codes off??

Thanks for your help
 

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There are three different types of O2 sensors for the P38s. Chances are your corner shop won't have them. Do you have enough good wire on each side of the melt to splice things back together just to get her running? While doing that I would pull all the plugs, give them a good spray with starter fluid to clean them off and let the cylinders dry out.
 

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2010-2012 Range Rover MkIII / L322
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In that case, make sure you get hold of a quality item, if not Genuine Part, then at least marked NGK/NTK to show it is OEM.
 

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Just to make sure you are clear - failed O2 sensors in themselves won't prevent the engine from starting you will need to look elsewhere as suggested for this. The fuelling for staring is not controlled by the O2 sensors. These only work once up to temperature and then allow the engine to go into closed loop fuelling. If the O2 sensors aren't working it will stay in a default open loop state which usually results in slightly rougher running, higher fuel consumption and poor emissions, but it will run.

Once fitting new sensors it would be worth having the adaptive values reset - it will need to hooked up to testbook or similar for this.
 

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As AllyV8 inferred earlier, if the cat has been running too hot for too long it wil be permanently damaged. Also, very high temperature can actually deform the matrix of cells/tubes inside the cat, essentially causing the cat to be almost sealed off. The engine will have massive difficulty turning over/running, if one side if the exhaust almost sealed. If you have a few hours, try disconnecting the exhaust "Y" piece, from both exhaust manifolds and the central siliencer (- also disconnect the wires to the O2 sensors). This will remove most of the exhaust system from the car (= very loud running), but if the engine starts, I would suggest that your "Y" section and cats have been toasted (= needs replacement).
 
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