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[05omegav6]

With a view to resolving my misfire, I've changed all the plugs.

Number 6 is missing its' nose. The insulation is chipped and the core electrode is missing.

Will this make it in to the exhaust without doing too much (ie any) damage? :-/ Yeah right.

I appreciate that it probably won't go through the cat, but what of the valves? :-/

Well there's a really nasty rattle from number 6, won't idle, it's hunting between 250 and 900 rpm, and sounds like it is running on 3/4 cylinders. Suspect its' days are numbered.

Fiddlesticksbockloks grrrrr.

[feeutfo]

Codes? Air leak? History, when did this start?

[05omegav6]

Morning,

Started yesterday am, nasty misfire lumpy/noisy. had injector code for number 5, and several misfire codes. swapped number 5 and number 1 injectors over and now no injectors codes. Also changed all 6 plugs. number 6was missing the entire central core and some of the ceramic from the tip.

engine runs/revs but very lumpy. no air leaks. codes read just now are:

0420, 0430

0300
0305
0300
0301
0303
0305
0306
0304

Just about to pull inlet assembly apart to try and see what damage is visible in number 6. failing that it'll be off with the head, not that i've the time to do it,but need the car on the road. :-/

ta
al.

[feeutfo]

Is the injector plug to manifold secure? Can't see why a possible compression fault and missfire on 6 would cause missfire issues on every cylinder except 2? Hunting/missing rough running, multiple misfires on all cylinders except 6 would have me looking at common issues to all cylinders.


 If issues on 6 remain after that's fixed then I'd worry about removing heads or fitting another lump.

[05omegav6]

had inlet manifold off, 6 was very wet fuel/oil not water. cleaned up put back together.
still ran like a bag of bolts, lots of rattling from 6.

stripped it off again, 6 very wet as before. just about to turn over by hand, wonder if its dropped a valve, hence the state of the plug :-/

If your interested, pm me your number and i'll text you a snap of the plug.

[Marks DTM Calib]

Smells like a MAF fault to me, any live data readings?

[05omegav6]

sorry mark, no live data.

plug 6 is missing its central core and outer electrodes both damaged. had to go somewhere. :-/

engine turns over by hand but is quite tight. :-/

[05omegav6]

p.s would a maf issue causea plug to fail?

also, can the car be run with the maf disconnected? would be quite useful if it can from an elimination point of view. :-/

[Kevin Wood]

p.s would a maf issue causea plug to fail?

also, can the car be run with the maf disconnected? would be quite useful if it can from an elimination point of view. :-/

Car will run for diagnostic purposes without the MAF.

If pot no. 6 has been seriously flooded it might immediately foul its' new plug on restart, so the misfire remains.

I would remove all the plugs and dry them, disconnect the crank sensor and turn it over on the starter a few times to try to dry the bores a little. While you're at it do a compression test just for peace of mind.

I can't see the MAF having destroyed the plug unless it was running seriously lean. More likely the last mechanic to change the plugs couldn't be arsed to change no.6 IMHO.

Kevin

[Kevin Wood]

Oh, and if the bores have been washed dry of oil, the compression may seem low. A squirt of oil in each bore will see it return if that's the case. We're really looking for valve damage which won't improve with oil.

[05omegav6]

last 3 plug changes (every 20k) been done by me. I might be lazy enough to drive everywhere, but I'm not THAT lazy. previous plug changes all done by TVP at Biscester.

There is enough back pressure to blow the combustion gasses back up the inlet manifold, and also past all 3 seals between the head and the plenum. Inlet valves appear to have no damage on their stems, or the back of their heads. Top of piston looks quite crappy,lots of black sticky gunk on it.

I guess the blow back would be enough to seriously upset the rest of the combustion cycle. :-/

Not promising anyway.

How much to fit a replacement head, assuming the piston is not holed?

[shyboy]

Could the broken plug debris still be in there?

[05omegav6]

stupidly i've driven about 50 miles since yesterday morning, hence my not being too optimistic about the whole situation. :-/

[Kevin Wood]

How do you know there's blow back? Any evidence?

I reckon it's probably still just a misfiring, flooded cylinder but a compression check will tell if there's a serious problem. 

Kevin

[05omegav6]

I cleaned the plenum inside and out at the cambelt meet, and again last week, trying to solve a slight fume issue. now there is alot of wet/oily mess inside the plenum above the inlet duct to number 6. it is also blowing past the seals above and below the inlet base plate, again only on number 6.