Black smoke

Ok, just when I thought I had a light at the end of the tunnel.........

When I rev the RR (4.6 petrol) I'm getting black smoke. The running is pretty rough and seems under powered. Seems a little hesitant to get off the mark aswell. Fuel consumption is very very bad. 6mpg according to the trip computer.
So far this week I've done:
1) engine flush, oil, change, oil filter change, air filter change
2) New plugs and leads.
3) 2 new lambda sensors
4)new MAF sensor
5) new brake actuator
6) 2 new front abs sensors (still showing abs fault)
7) 2nd hand ultrasonic detector (that cleared the alarm fault)
8) cleaned stepper motor.

I'm starting to get a little peeved with it now!! It also smells quite heavily of petrol when I'm driving, but there are no obvious leaks.

Any ideas on where to go next???

Whats the air filter like ?

Badly over fueling. Did you have it on diagnostics before fitting all the bits or were you just guessing. Guessing i presume. Find someone with diag it could have saved you a fortune.

I got it plugged in and it came up with both front abs sensors ( I changed them and the light is still on).
And it came up with an o2 sensor so I changed em both.
Everything I've changed it needed, the only "guess" part was the MAF I replaced today and I was sort of hoping that might have sorted it
I haven't even had the damn thing a fortnight, so all the service items I would have done anyway, inc plugs and leads.

mightywolf said:

I got it plugged in and it came up with both front abs sensors ( I changed them and the light is still on).
And it came up with an o2 sensor so I changed em both.
Everything I've changed it needed, the only "guess" part was the MAF I replaced today and I was sort of hoping that might have sorted it
I haven't even had the damn thing a fortnight, so all the service items I would have done anyway, inc plugs and leads.

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OK but it is dramatically over fueling for some reason, so i suggest you get it stuck back on diag.

Unusual for black smog from a petrol ? First for me ! Lol

It is unusual, but not unheard of...

Usually means it is overfuelling or heavily carbon deposited...also could mean the exhaust system is fouled too....

Wammers, is it possible to reset the fuel trims on the 4.6?? He doesn't mention year, and I am guessing only certain years were resettable...could the fuel trims be way off causing a chronic overfuelling??

sorry should have said, its 1998 4.6 ltd.
Poor thing looks like a diesel when you put your toe down

Saint.V8 said:

It is unusual, but not unheard of...

Usually means it is overfuelling or heavily carbon deposited...also could mean the exhaust system is fouled too....

Wammers, is it possible to reset the fuel trims on the 4.6?? He doesn't mention year, and I am guessing only certain years were resettable...could the fuel trims be way off causing a chronic overfuelling??

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Think it maybe something more than fuel trims. Only diag can help him i would think. Crystal ball a bit foggy to night. Won't be doing his cats a lot of good either.

if you keep moving about your driveway and revving it you can re-tarmac your drive for the price of pertol

What about dirty or knackered injectors dumping fuel in some of the pots instead of spraying it in just a thought.

Just found an old thread about this and it turned out to be the engine ecu at fault? Symptoms seemed identical to mine and after replacing everything like me, it seems the ecu wasn't sending the correct signal to the lambda sensors and messing up the fueling.
I have a feeling its been running like this for a long time before I got it.
Had a quick look on the flea bay and second hand ecu's ain't too expensive. Might be worth a shot?

fett said:

if you keep moving about your driveway and revving it you can re-tarmac your drive for the price of pertol

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Now your laughing at the thought of that but it really does leave black sooty spots on the drive underneath the exhausts lol

Did you ever get to the bottom of this problem ?

wrong plugs?

If compression & leads are good then ECU sounds like a good starting point to me.

gfromleeds said:

wrong plugs?

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Yeah maybe two stroke plugs would be better.

wammers said:

Yeah maybe two stroke plugs would be better.

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i ment gap size
but yea