Disco 2 misfiring

[GPDISCO2]

Hi Guys,

I've been through a lot of threads put could not pick up if this was discussed before.

I've got a 2000 Discovery 2 V8, recently I experienced a lack of power (sound to me like it's a misfiring) from idle to about 2000rpm. When I step on the gas it hesitates a bit and then pulls OK, once above 2000rpm. I've check for a spark on all cylinders and numbers 6 & 8 had a much smaller spark (almost non) compared to the other cylinders. I've swapped the coilpacks (an old bunch that came of the truck got it from the previous owner who changed it when in fact the MAS was faulty) in any case it was a hell of a job, especially if you do it without removing the intake manifold. The truck is pulling slightly better but the misfiring is still there. Last night I pulled the plug out of the MAS and drove it home like that, could not even tell it wasn't connected, the misfire was still there. When I got home I plugged it back in and the truck idled a bit better. This is a lot of info but I though the more you know the better advice I can get.

What I would like to know is what else could be wrong, it seems to me the MAS and coilpack is OK. I do not have any code reader.

Cheers,
GPDISCO2:angel:

[AussieAub]

Had similar probs to what you describe a while back.
Have you got a slight "fuel smell"? (see below)
Mine turned out to be dodgy O2 sensors.
Gave almost identical symptoms.


When I step on the gas it hesitates a bit and then pulls OK
Overfuelling symptom due to O2 sensors (as I was told).

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
Object Of Mass Consumption
AussieAubs Disco Page (http://aussieaub.blogspot.com)

[bee utey]

Had similar probs to what you describe a while back.
Have you got a slight "fuel smell"? (see below)
Mine turned out to be dodgy O2 sensors.
Gave almost identical symptoms.


Overfuelling symptom due to O2 sensors (as I was told).

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
Object Of Mass Consumption
AussieAubs Disco Page (http://aussieaub.blogspot.com)

Very likely. It's a Bosch system, 4 wire heated lambda sensor, 0Volt lean, 1 Volt rich output. From memory you can access the LH oxy sensor plug from above, the wire corresponding to the black wire from the sensor is orange in the loom. Test the sensor with a digital volt meter, the output voltage should flicker up and down around 0.5 volt while on light throttle. When you floor it the ECU goes into open loop mode, ignores the oxy sensor input. Commonly oxy sensors die after aboud 150 000km, should be replaced much earlier for best results.

[GPDISCO2]

Hi Guys,

Found the problem, the Airflow Meter was stuffed. Cost a few $ to read the fault error codes and the only thing reported was the MAF. Bought one on ebay from UK on $75. The truck is running like new!

Cheers,
GPDISCO2

[ted2910]

Hi mate, I recommend getting one of these scangauge, Cars, Bikes, Boats, MG, Porsche items at low prices on eBay.com.au (http://shop.ebay.com.au/?_from=R40&_trksid=p3907.m38.l1313&_nkw=scangauge&_sacat=See-All-Categories) The scangauge is great for the V8's and not all that expensive too! I bought one a few weeks ago and have never looked back, I found various fault codes that I never would of known about.
Tells you some pretty handy info aswell.

Cheers Ted.