03 2.0 mk4 with APK engine. Lumpy idle & rich mixture, after alt short. One for JMac?

[lobe]

G'day,

Sorry for the waffle but here's the background info:-

Happened to drop a driver extension & it touched the wiring near the alternator, for a split second, giving off a tiny spark. Very slight coolant weep from thermostat flange (behind the alt)which i was looking at.
Finished checking fluids and topping up with abit of oil (uses abit, nothing too alarming - read about the oil use here & on other forums when the missus bought the car 6mths ago).

Started car - all good, idle ok, no probs etc.

Went out later that evening in car and noticed strong/rich mixture smell. Didn't think too much of it as there happened to be a car & RAA recovery van trying to get this car going, as my lift dropped me off so just assumed the smell was that.

I did notice the mixture smell again as the missus came home from work in the car the next day. Idle was lumpy too. I'm pretty mech minded & notice stuff like that straight away.

I whipped the plugs out and they were quite black, not oil, just soot/carbon. Plugs are BOSCH FGR7DQP+ ( which europarts supplied, although i would have preferred NGK spark plug BKUR6ET-10 ). Prob been in the car approx +8 wks.

I had read comments before re non NGK plugs and coil packs (although assured by europarts they'd be ok) so i popped the old plugs back in i still had. These were some brand i'd not heard of - Titan X or some thing, hence why i changed them in the first place, still a 4 pronged plug though, and prob fit by the previous owner/independent vw workshop who serviced it.

Still the same smell, after running car approx 5 mins.

Checked all the breathers, hoses - couldn't see any problems, leaks. Removed throttle body, looked ok, clean etc.
MAF also looked ok, no oil etc. Gave it a v slight clean with contact cleaner and caught cleaner in a container - was very clean. Left overnight.
Note : I didn't run it with the MAF disconnected to confirm if the idle improved with the default settings, nor any of the other sensors as didn't want to throw codes, which i'd then have to explain to the vw specialist if i ended up taking the car there.

Disconnected battery, cleaned contacts - abit dirty, cleared any residual current out of system and left till next morning, to see if it would reset the ecu. checked all fuses - all ok.

Missus uses car the following day - no problems - idle good, no smell, all back to normal and drives nice. Running at 0.9 i think on the dash fuel computer on idle. Whipped plugs out. Not bad.

Whilst out on an engineering job today, I went to vw specialist in town who'd serviced it who confirmed what i could see in the history p/work. Car had some of the usual suspects changed say 12-18mths ago - O2 sensor, coolant temp sensor and a new thermostat.

They did say they have no history of a MAF been fit and the car has done 172k now so probably due one.

I guess i'm wondering if the very brief short on the Alt wiring was just a co-incidence, or whether it caused a glitch/the problem.

I always have a look over the golf if i'm working on my dirt bikes, road bikes or my car and its normally v good. Missus knows not to put any old petrol in it and she had put bp 98 in the day before, from a local garage who would tend to sell a lot of 98. Getting her to run it low then fill from another servo anyway, just in case, prob Shell V power.

Like i say, car seems to be fine but i would like to know more if possible. Any ideas. Any comment on the ngk v bosch plug scenario also?

Thanks
Lobe

[Speed]

So the problem has gone away now?

[lobe]

Yep, car is fine at the moment.

Still got the old plugs back in it though. Planning to run it for a week or so then have a look at the colour of them, see if they're covered in heavy soot again.