Effing thing

[Stanky]

I wonder if anyone can help me track down an issue with the Kia Rio.

 

Its up for sale, but it knows so it has started misbehaving. The symptoms are it being jerky when accelerating, usually when it is warm but very occasionally when cold. It is worse in lower gears and at low speeds. Sometimes the EML comes on, but I think this has been cured to an extent by cleaning and re-fitting the MAF.

 

I have cleaned and re-fitted the MAF after the replacement one fell apart in my hands, while I was at it I gave the throttle body a damn good clean with carb cleaner, a rag and a toothbrush. It was very grubby. The air filter is fine (replaced ~3k ago) - what else could it be?

 

Plugs are a possibility, though I'm not sure why being hot would affect this, the Coil pack is high on the list of possible offending parts but I'd prefer not to just start replacing things until I find out what is wrong.

 

Any suggestions? It picks up fine at higher revs, but the bastard thing just seems to be misfiring or over/under fuelling at low revs and no-one is going to buy it in its present state.

 

edit - it starts, idles and will hold a constant speed fine, it's ok on the motorway in a noisy kind of way. Its just when pootling around locally that it seems to do this.

 

Suggestions?

[r.welfare]

Pull the spark plugs and check gap/oiliness/general electrode condition.

[Stanky]

pulled #4, not oily, tip is discoloured slightly brown - sort of rust colour. I think this means they are OK and the mixture is about right?

 

How do you check the gap? feeler guages? Is there any other option as this is a tool I do not possess. Also, how do you adjust the gap? A hammer I assume?

[r.welfare]

Yes, feeler gauges and just push the tip against something to close the gap; a small screwdriver in the gap and twist to widen.

 

I'd pull all four to be sure. It could be a leaking rocker cover gasket dropping oil into the plug holes.

[Stanky]

The plug holes are all dry, one was inhabited by a very very well cooked moth which has now been extracted. All plugs are in similar condition - light brown, no oilyness?

 

Hmm, I shall see if frau_Stanky's uncle has a set of feeler gauges as I did find an article that says the electrode gap needs to be between 0.28 and 0.32 or they can be grumpy. Bloody things.

[catsinthewelder]

We always used to check the gaps with rizla packet when I was a teenager. You don't need a hammer, just hold the plug and push it down on something solid if the gaps too big. On something older I would pull the rest out as well to see if any of the others are different but it's probably easier to just read the code on that.

[Clanger]

one was inhabited by a very very well cooked moth.

What kind of moth was it? Some of the earlier moths can break down causing the symptoms you have described. Try installing a new one and see if that cures it.

[Stanky]

Aaah, of course. Incompatible moth. Error code 001-M0TH.

 

I'll see about sourcing an OBD2 code reader so my worst fears can be actualised.

[Stanky]

Well, it's not my problem any more. A good dose of carb cleaner, taken up the slack in the accelerator cable and a bloke came and bought it for his daughter to learn to drive in.

 

I am a terrible person, but I have come to terms with that. I am also £650 richer which will go towards paying off various tabs and leave me with enough to get the Nissan re-taxed and back in the game, plus a meal out for the family.

 

I kept the moth though.