Troublesome starting and stuck spark plug...

Troublesome starting and stuck spark plug...

Author
Discussion

franv8

Original Poster:

2,212 posts

245 months

Tuesday 22nd July 2008
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Hello all,

Been having more and more trouble starting my 1.6 Eunos (1990) - basically it tends to start on 2 cylindrs from cold and then decide after a rev to clear its throat that it'll have all 4. This is accompanied by a smell of neat petrol.

I suspected perhaps I had some plugs going down, so I had a look and they looked generally fine, except No2 which I could get to turn, and rocking it back and forward got it to move two turns in both directions before, for no explainable reason or obviously visible damage, the plug wrench decided it no longer wanted to grip the plug (doesn't look rounded off and it hasn't snapped and started spinning of its own accord).

Any ideas on the poor starting? I wondered if I have a coil pack going down? Car runs very well once past this starting problem.

I've got magnacor leads btw, they're only a couple of years old.

Any tips on plug removal greatly welcomed too! Otherwise I guess it's head off time...grrr!

OnlyMX5ives

1,142 posts

199 months

Tuesday 22nd July 2008
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I've had this twice before both times it was a faulty AFM.

Once it was the temp sensor had broken, once it was the flap not fully closing.

Both give rich running at start up.

IME Magnecores are rubbish - at best their quality control is poor, I've had them break within a week.

Re Plug are you sure you're using the right socket - several have reported similar but been using poor / incorrect tools. You want a 6 sided socket NOT multi.

franv8

Original Poster:

2,212 posts

245 months

Wednesday 23rd July 2008
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Thanks for the reply - it was a 6 sided socket, and it's all a bit weird, since a look at the plug in its hole with a torch shows it not to be chewed up, I thought perhaps the socket had decided it didn't want to 'reach' over the hex flats so messed about with that too. I've bought some more sockets tonight, but I'm thinking of leaving it for the moment since it's working and about an inch on the gas pedal gets it starting pretty much right, feels like a traditional old car now - with the old knowing exactly where to set the manual choke for starting!!!! I bought a smaller socket too, in case the hammering over the plug approach is needed...

Any ideas of the most cost effective way of getting an AFM and the cost...

princeperch

8,026 posts

254 months

Wednesday 23rd July 2008
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Funnily enough i'm going to have a bosh at changing my sparkies next week.

The present ones were only fitted a little over a yr ago when she was last serviced, but it is only a case of noting which ones connect where, removing the olds, greasing up the new ones, and screwing them in at the right torque?

zac510

5,546 posts

213 months

Wednesday 23rd July 2008
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You really should use a proper spark plug socket to get the plugs out.

skinny

5,269 posts

242 months

Wednesday 23rd July 2008
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i had real trouble removing my first set of plugs to the extent i covered the end of the socket in something (can't remember what) to see if i could figure out what stopped it dropping over the plug. as i recall, the walls of the hole actually narrow towards the plug, and a narrower socket got them out ok.

think i have magnecors, KV80's or 85's possibly. they are blue anyway! but have lasted for 3+ years and still going strong (and were on before i bought the car too)

GreenV8S

30,482 posts

291 months

Wednesday 23rd July 2008
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franv8 said:
rocking it back and forward got it to move two turns in both directions before, for no explainable reason or obviously visible damage, the plug wrench decided it no longer wanted to grip the plug (doesn't look rounded off and it hasn't snapped and started spinning of its own accord).
That sounds as if the plug spanner wasn't engaged properly. For example if the spanner is too big or not pushed down far enough to engage full then the side of the socket might still jam in between the head and the plug well enough to get some drive to the plug. Then as the plug starts to come out the socket clears the head and no longer has drive.

That's something that should never happen and indicates you're either using the wrong socket or not engaging it correctly.

Are you certain that the plug has been tightened up now? If you're running with a loose plug then that cylinder will be down on compression and reluctant to start, and you also stand to damage the head if you run it like that for long.

franv8

Original Poster:

2,212 posts

245 months

Wednesday 23rd July 2008
quotequote all
Originally (and to this point) I have only been using the proper '10mm' (it's actually 16mm across flats) spark plug socket, with the rubber cone for holding the plug in the socket too. Rememebr it was fine taking and putting back in the other three plugs, and it's also the socket that's done many a plug remove/refit on this car before. I think the root of this problem is the plug galling in it's hole. Yes, it is done up at the moment, but if it did decide to wreck the head, I'm not so sure I'm that far off it anyway - unless I take the head off and take it to a machine shop to have it bored out.

Using the 'wrong' sockets (i.e. deep ones) is an attempt to get a slightly better fit, (or tighter at least) - if it breaks then I'd be there anyway, so it's an act of desperation...

.. or would be, other than I don't think the plugs are the problem, very suspicious of the AFM (Will this throw a code btw if it fails as mentioned in one of the earlier replies?), so I might just leave the plug in until it really warrants changing, and face up to the issue then. (I know, why put off the problem until tomorrow etc. - and it may cause a bit more damage)

If it comes down to being head off job, I'm a bit more up for thinkin of a s/h engine, bearing in mind to take the head off and put it back on I reckon I'd be £200 down before getting any repairs done to the head itself. It's done 100k miles so if I was going to do that I'd want to do the stem seals/guides/valves and probably a rebore/re-bearing/new pistons, s/h engine prices then? Seem to have spotted some around tinternet at cheap prices (NOT reconditioned engine places, I give them a VERY wide bearth!)

princeperch

8,026 posts

254 months

Wednesday 23rd July 2008
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christ. all this talk about fking your engine up has got me a bit concerned.

Might leave the old plugs in when doing the service in this case...

franv8

Original Poster:

2,212 posts

245 months

Wednesday 23rd July 2008
quotequote all
I wouldn't be concerned, and in fact I would advise you do whip the plugs out, but reinstall them or new ones with a dab of copperslip on the threads.

Remember though, when you tighten them up, it's something like a 20 degree turn if they are taper seated plugs (no washer) or 90 degree turn at the end of they are with washer. (But don't go mad even if the final tighten is not this far - they don't need to be silly tight)

OnlyMX5ives

1,142 posts

199 months

Thursday 24th July 2008
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Remove the AFM from the filter side and check the door is fully closed.

Not sure if the intake air temp brings up a fault code - quick look in the manual / google should confirm.