4.6 running very rich

Hi all,

I've recently become the owner of a 1995 Range Rover 4.6 HSE. I like it a lot but it's unfortunately running rich.

I thought the fuel consumption would be fairly excessive, but only really decided to investigate when I took note of mileometer readings.
£25 of unleaded did less than 50 miles, on a mixed journey, ie a roads, some stopping at traffic lights etc.

I checked the spark plugs and they're sooty black, but the tip is slightly better-



Is this normal or should I expect light brown plugs as per usual.

The tailpipe is also black/ sooty and the exhaust noticeably stinks quite a lot when I've just reverse parked.

Other info-
It has a single-point LPG conversion, not ideal I know but it works fine. However, it also runs rich on gas.
It starts, runs and performs as it should- very powerfull when using kickdown.
It has the Mark Adams 'Tornado' chips.

Any tips to get those plugs correct?

Many thanks

did u try reading ur ecm?any faults found?i suggest u read ur faults first if any is available

Hi Jorjio K, I have not yet read the codes- I am new to Range Rovers and expected to see a engine light illuminated on the dash, do they not have this?

Incidentally, I am not using gas until the petrol running is correct. The plug in the picture is 10 miles old, the originals were just the same.

I notice that one of the last invoices to the previous owner was for a new ECM coolant temperature sensor, the lambda sensors are both new too...:suspicious:

Sounds like it needs re-mapped especially if it's been chipped. Are these the correct grade of plug? Fuel pump? Think you need it plugged in to tell why it's overfuelling.

Hi Hippo lover!

I agree, I need to get it plugged in to see what's going on, I've phoned a few people- only one seemed confident that he could properly assess a P38.

However, I have made progress.
Looking through the previous receipts, I noticed both O2 sensors had been replaced, along with the coolant temperature sensor. The previous owner must have noticed a problem too.
I removed the Air Mass Meter to check it, and gave the internals a good soaking with carb cleaner.
I then went for a good run on petrol, and achieved 20 mpg
The plug tips are now clean, although the surround is still black- is this more normal?



I'm still having a scan done (maybe a reset of the long-term map?) but I'm much happier with the mpg now.
I will also buy a new AMM. The car has a cone filter, which I'm not overly keen on but will have to stay for now. I wonder if the (oiled?) filter has contaminated the AMM?

David.

The gems engines need a fair few miles to adapt to any new parts fitted on the fuelling side, so a reset of the long term trims is always recommended when fitting new or cleaning old parts. I would suspect the MAF to start. You say you have squirted it with carb cleaner but I would be a little more thorough and get in there with a cotton bud. Be gentle ! And then have the adaptions reset. Fit a new set of of NGK BPR6ES plugs while your at it.

Hi Rewmer- I am enjoying learning more about the GEMS system, it seems slightly different to other systems of it's time. Having to have the trims reset is slightly annoying every time something is replaced, but I suppose Land Rover always thought owners would have main dealers do all repair work!
I will clean the AMM again. Question regarding this, should there be a tiny hole at the back of the centre part that houses the wire? There wasn't on mine... but after a thorough clean.. there was!!
The new plugs pictured are MGK BPR6ES's- I have a Halfords trade card and they are a bargain £5.89 for a set of 4 with the discount