Ok here are the details
2003 Disco II HSE. V8 4L w/SAI, Petrol Engine (2 years old, replaced original engine)
It is a right hand drive model as I live in New Zealand
Also replaced the exhaust manifolds and the down Y-pipe along with both Catalytics.

Put new O2s in all around (so 4 new ones) but just as with the old engine, I keep getting the Service Engine Ligth illuminating and it is always the O2 sensor codes that are popping up. I have replaced them 2 times in the last 18 months. I also replaced the MAF, the Temp Sensor, the Fuel Pressure Sensor under advise from the Land Rover mechanic here.
Still getting the bloomin' O2 sensor codes.
Have to admit I am not using original O2s because they were way too expensive (close to $300 each here in NZ). I ordered a pair of front and back from British Parts in the UK for something like $65 each.
Now I am just annoyed because with sensors out - even with a new engine, I am still getting crap fuel economy and the occasional sluggish acceleration. Not much else that can be replaced I reckon. I have been told it could be a vacuum leak. Have not had time to check that....but I have inspected pretty much every hose that - big and small, and cannot find any leaks (well to be honest in checking once...I did uncover a leaky coolant hose going into the firewall (f/or the heating system....caught that before it became a disaster.)
Any ideas

 

I am having similar issues... I have trouble shot the harness, ECU and replaced the O2 sensors multiple time. I would be interested in hearing how your issue progresses, might help me.

Cheers!

 

If you can attach a code reader that has dynamic data you can look at the voltage of the o2 sensors. The voltage should be switching back and forth between 2 values(not always the same but close). The fronts are usually more active than the rear.

If they are not, start twisting the harness looking for issues with the wiring. Also you can play with the connectors at the ECU.

This seems like a common problem and in my experience ends up being 50/50, bad wiring harness or bad ECU.

You could also try splicing in new wires direct from the ECU plug to the o2 sensor.

Good luck

 

I do have a computer which can read dynamic. Soon as the wife returns from work this arvo I will be plugging in and taking some readings.

I have not played with the wiring harnass for the O2s at all....I do know that sometimes voltage readings can be dodgy in particular if there is a ground wire issue (dirty, not well grounded, rusty etc).

I checked all the grounding points under the hood - they are all clean and tight - I find no reason to suspect them.

Now that ECU issue - that is something that has crossed my miod many times - in fact when I was doing research to purchase the new engine 2 years back, I was extremely tempted to order a new ECU, one that had some ability for custome user programability (Just because). I never did it, but the ECU thought has stayed with me....

Well - process of elimination - I will get the readings, wiggle some cables, check grounding....AND if all else fails, I might just go fpr a new ECU....(then at least I have covered all the bases before blowing the car up in a fit of rage! (lol)

If I get to ECU stage I will consult the forums for recommendations.

 

Guess I will be reading these codes for the O2s sometime tomorrow. Given that the truck is now out of commission.
Had an engine cut-out at a red light (city driving). Restarted right away.
Later in the day went to grocery store. On return to vehicle, it wont start.
Battery reads 12.7 volts and is holding charge so it appears alternator is charging it.
All lights n everything very strong. Cranks over but wont start - wait about 15-20 minutes and boom it started...>SUSPECT CRANK SENSOR> so will be checking that out tomorrow along with all other ailments
Starting to get annoyed with the DISCO II Attitude
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