Well I was tinkering with my new pride and joy a 97 Disco V8, knowing that it wasn't running quite right and the reason I got it for a good price (for Australia!) You guys would not believe what these things still fetch down under!!
After checking all the sensors, I checked the voltage on the MAF. Now, this should be around 1.0 to 1.5 Volts, but mine was reading 3.3V !!!!!! no wonder it felt lumpy, drank fuel and sooted up new plugs in an instant. Well I set it to 1.3V which is a good starting point and it is a good deal smoother and more responsive now but still doesn't quite feel right, so now I'm thinking ignition timing. If the MAF was that far out who knows what they have set the ignition timing to. Now I know you can't really trust the timing marks on the crank pulley so I'm tempted to just ease the distributor round until it sounds and feels better. Provided it doesn't pink on load it should be better than it feels now. At the moment it still kind of shakes and doesn't feel free or wanting to rev. It seems to be firing on all eight. My gut tells me its too far advanced but I can't get it to pink. However, it is an Auto so its difficult to labour it. Any thoughts?

 

My 97 has no distributor, the ECM controls the sparks from the sensors.

The factory tech manuals are a free download below, called the "RAVE" - which must stand for Rovers A'int Very Economical. Manuals cover all Land Rovers for a wide number of years, you may need to poke about to find your engine, as some models rolled out in different years around the globe, and the US versions have plenty of emmissions control extras.

Of course, you could also have a sloppy stretched timing chain under the front cover, if going in there plan on water pump and oil pump at same time.

 

Only the NAS versions up until the DII have distributorless ignition, the rest of the world used the 3.9 with a dizzy.

Start with the ignition timing and work from there.
Yes it is going to be hard to "lug" the engine with a autobox, you may just need to carry a spanner with you and adjust the timing as you go about your daily business.
The timing marks would be a starting point, but then adjusting by "feel" would be the fine tuning, also make sure your vacuum advance is working.
If not you can replace just that and not the whole dizzy.

How do you adjust the volts on the MAF?

 

I refer to the RPI website. I really trust the advice these guys give. If I was back in UK I would use a CO analyser as well but I've only got limited tools with me in Canberra.
RPI recommend adjusting the mixture on the MAF using the system voltage as a good guide.
Run engine up to temp. find the connector on the MAF push a sewing pin through the grommets on the back of the plug of the Blue/Red wire and the red/black wire.
Measure the volts between these wires. It should be between 1.0 and 1.4 Volts for a non Cat 3.9 i.e what we have in Australia. If it isn't remove the anti tamper plug on the boss on top of the MAF control box and adjust the screw until the volts comes into the right range. The screw takes about twenty turns from one extreme to the other so the adjustment is quite fine, e.g. a lot of screw movement to make much difference to the voltage reading.
For a UK version with Cats this voltage can be higher, even up to 1.8Volts because the Lambda sensors will control provide feedback about the mixture and influence the mixture setting over most of the rev range.

This will give an approximation to the right CO reading but obviously other factors like ignition timing etc will have another influence.

 

I did not know we could adjust our MAF's, I imagine with the NAS version and having a OBDII port (I can read MAF volts with my scanner) that it could still be adjusted only using the OBDII scanner instead of a volt meter.
Pretty cool, that you for letting us in on the secret.

 

sounds like an mpg tweak to me. A post from a while back references the voltage, but mentions that may be two versions. https://landroverforums.com/forum/di...dle+surge+cold

Having said that, we'll now be seeing a batch of 0103 and 0104 codes....

 

I know I'm not messing with mine, if it ain't broke...

 

amen.