Is this Rich lean or correct?

[Ian Anderson]

My past experience has been on cars running leaded fuel and checking colour of plugs and exhaust gave the tune of the car away.

This is plug from number 5 cylinder on the Dax which is a NGK BP6ES in a Rover 3.9 EFi running Unleaded fuel

Rear of exhaust is black - but I know with unleaded that means very little - so he are pics of the plug

Does it need adjusted?

Thanks
Ian

 

[Joe T]

Are all the plugs roughly the same as this one? or did you pick this one specially.

To me it looks fine, I can still make out the white of the porcelian holding the electrode, and there does not look like any buildup on the tip of the electrode. If anything it may be a little rich, but if you only do short journeys plugs can stay dark. If you do a lot of high speed travelling you could try weakening it a notch and see what happens.

If it was darker, no white of the porcelain showing through a black soot coating, then defo too rich etc.

A CO meter is the only real test,

 

[Jac Mac]

Ian, Did you remove this plug after doing a 'Cut' or just remove it after a run.
As Joe T has stated unleaded doesnt give conclusive readings like the "Good Stuff" used to.

Jac Mac

 

[Ian Anderson]

Ok the story

At SVA the tester (I liken him to a certain German!) said the emissions passed but it was running lean - he would not quantify.

The engine is all brand new 16 years ago then sent away for a pile of hot bits and balancing etc. and ran for the first time this year.

I have now done about 150 miles on the car and this still niggles as to me lean = hot = expensive replacements.

I have tried 2 Landrover / Rangerover garages and one Rover one - none will give me the time of day and all sat unless it is in one of their cars they will not look at it.

In the meantime on the last couple of runs the engine seems to be running smoother and even idles instead of dying. I also found I had a dying / dead battery and perhaps at idle with fans and 2 fuel pumps etc running the fuel rail lost pressure to give the lean readings - again who knows?

Electronics to me is a black art and hence I leave to the experts - I'd love to see how they check and set these systems but they are welcome to the job.

cheers
Ian

 

[Ian Anderson]

Plug was chosen as easiest to remove

Car was run around the streets - about 10 miles or so, last bit (mile or so) has slow stuff 30mph and traffic lights.

Engine is only happy above about 1800 rpm - try to keep under 3000 as she is still so new and Rover people say 600 miles below 2000 and 500 more for each 100 thereafter. - slower than that and the water flow seems to reduce and water temp rises then stabilises.

Cheers
ian

 

[Joe T]

Ok, I think I would put more miles on it before worrying, it does not look too lean. You are right too lean is the more expensive setting as it can cause hotspots leading to engine damage, but you normally get a lot of signs. Misfire, pinking, generally poor performance.

To put you mind at rest drop in to any garage, most have a CO tester and ask for a print out. I am assuming yours does not have a CAT fitted due to the SVA testers comment.

He might be thinking of a older carburated rover V8 and comparing your reading to that.

I have a CO Gas analyser but your a fair trip from me.

Cheers

 

[John W]

Ian,
a mate of mine works in a range rover dealership.
I am guessing you would like him to connect up the diagnostics kit to your car. Chances are this would require you to get the car to him, unless it is something he can perform using a laptop and appropriate software.
FYI he lives in Addlestone, so not far from you.

I will ask him if he is prepared to have a look when I see him later in the week.
Please send me an email on Wednesday and Thursday to remind me as I am likely to have forgotten by then ! oke:

Cheers,
John.

 

[Ian Anderson]

John

that would be brilliant if he could and he obviously would have knowledge of the sensors etc and what they should be doing.

I'll give you a chase up as requested

cheers
Ian