Oppps apologies a rookie error post from me! What I should have said is Yes when I remove the plug from 4 NOTHING happens! Doh! sorry about that. So No.4 is where the problem is.
Sorry got muddled up, no.4 removal made no difference, see my reply above
This is good to know. But with the original leads on there is no spark so they would not have seen that but yes they should have noticed it not running smoothly. Its when I put my brand new leads on there is a spark on No.1, (second one in from near side). Also as you’ll see from my reply t. So o another comment above No.4 is definitely not firing. So is that unconnected problems then? No.4 not firing and an open circuit on No.1. I will put the old lead back on No.1 tomorrow as that is not sparking so I figure wont cause this other cat damage. Can you have an open circuit plug problem without seeing any sparks?
Yup could be a duff plug as someone mentioned, not good that Ive been back there already and after an hour been fobbed off with “…get some new HT leads thats definitely it”, I didn’t know to ask all the questions that I now know to ask about plugs from these comments, you’d assume that they would have looked at the plugs again but maybe the mechanic assigned to it didn’t bother and just said that. I will quiz them when I go back in. Its frustrating you just get to speak to a service manager at a desk and not the mechanic but she said the head mechanic will be on it so I will insist on putting my questions to him.
I take it you have checked that the leads are connected for the correct firing order as Safetymatch has suggested.
I once bought a car very cheap (for spares) because the owner could not get the engine to run properly. He thought that the valves or piston rings had gone. I got it home to find that the leads had been fitted incorrectly. Swapped them round and hey presto the engine ran sweetly. I bet the seller would have spit feathers if he had known!
In the last para of your original post you say that a spark plug blew out in 2010.
Do you know which one, why, and what was done to correct this(eg helicoil)
Wonder if this was due to a crossed thread and if this particular plug has been incorrectly fitted again?
Think this is where I’d start looking first.
Thanks for the post, wow well that was a find!l I was waiting for a reply from Safetymatch, can’t seem to multiquote either so here is my reply to Safetymatch below and at the end is a link to a photo of my lead connection as it was after the service, and this is similar to other lead connection pics i have seen on this and other forums. Please take a look. Thanks
Thanks for the pic but the coil pack in that diagram looks different to mine, but the main difference is if that’s how its situated behind the engine with 4,1,2,3 from righthand drivers side to near side those connections are the opposite way round in mine, see my photo, I have also seen other pictures showing them connected how mine are.
>>>>>Can't post a picture for some reason, maybe as i have free membership anyway its here: https://www.dropbox.com/s/l1ghjxd16at8leg/IMG_7197.JPG?dl=0
Yes, good point, they have the full service record on their system but I assume they did not check out this point or didnt think it was relevant to mention this to me after the service, this was one of the things I intend to point out to the head tech on Tuesday. My dad remembered this happening and so I went through the record and this is the report:
11/5/2010 - Intermittent misfire @2000 rpm. Remove spark plugs and leads, No 3 lead badly scorched and lead breaking down. Remove and replace spark plugs and HT leads. Test, all ok. cost - £191
12/6/2010 - 1 spark plug has blown out of the engine. Recoil repair number 3 spark plug hole in alloy cylinder head. Replace single plug. Test, all ok. cost £292
Dad says that he reckons they didn’t fit the plug properly in the first place as you suggest.
Are there any members in Didcot with a plug spanner who could pop over and have a look at this car ?
That’s a very kind suggestion Raymond and it would be good to know if there are any MK2 owners who are local and know a thing or two about these sorts of issues. But at this stage I don’t want to touch anything they’ve done (apart from changing HT leads as they said needed to happen) I’ve just got to wait and see what happens when it goes back in for them to fix on Tuesday.
So as it stands from my investigations:
1/ Spark is not getting to No.4 cylinder. I have tested all cylinders by removing plugs when running.
2/ Old HT leads no sparks. Brand new HT leads 2/3 sparks at coil pack end 2nd from right nearside. This lead is connected to No.1 cylinder. Should I be sending back these new leads as faulty? But also what should I return to the garage with on Tuesday? Old leads on, new leads with spark or new leads with an old one replacing the sparking one?! Whatever I do I think i need to give them all this information to help diagnose, but I dont want them thinking oh he didnt get us to replace the leads for a high price and put some leads on badly or the leads are rubbish! Is it safe to assume it initially was not a lead problem?
3/ Recoil repair was done to No.3 cylinder in 2010 but that ones working and not connected to the problems above.
4/ Still confused about the diagram provided by safetymatch. My connection is back to front, see here: Dropbox - File Deleted - Simplify your life
I am also confused. Picture here https://www.mx5nutz.com/forum/index.php?showtopic=59046
Think your one is ok.
Yes! thanks for posting I’m sure we are correct!
If the coilpack were playing up, it would likely be one of the two units where car still running, so either 1 & 4 or 2 & 3 would be affected.
From your description it is beginning to sound like a shorted spark plug on a single cylinder - perhaps the bottom electrode got a wack and now no gap?
I would not drive that car anywhere as the misfire will introduce neat fuel into the exhaust and kill the cat.
If the garage are not prepared to visit you and sort out what appears to be their problem, I would do the work myself or employ someone else to sort it at your house.
A report could then be compiled and the appropriate action taken against this garage.
Beggars belief that they let you drive away a car they have effectively crippled - well done getting home!
The garage would have to check and make sure the spark plugs were all good, inserted correctly, leads fine etc before resorting to this though. So all other things were eliminated before a reader ‘tells me there is no problem’ or it would be falsely diagnosed, correct?
looks like we were writing at the same time! Just replied to your other post. Wow this is worrying I better get on the phone to them now. Thanks.
Absolutely, yes - the garage should have noticed that the car was running on three cylinders unless the fault occured after you left them on the way home. Removing the contentious spark plug will hopefully reveal all.
In any event I would get that error diagnostic code reader. It will put you in a stronger position to at least know what problems the car has and it is a good entry method to understanding the basics so a garage does not necessarily get to mess you around.
Big thanks for your other post, potentially damaging the car got me straight on the phone and made a complaint to the Service Manager who I’d not spoken to before. Gave him the full lowdown on whats been going on along with our extra diagnosis. He spoke to the tech and called me back and escalated it so I’m taking the car in first thing tomorrow for them to diagnose and sort out. As far as the CAT goes the tech advised that its ok to drive back. I told him how much the car has done since the first visit, 81 miles and it will be another 15 going back in. So fingers crossed its all their fault and it gets sorted.
Is this the reader you mentioned? Diagnostic connector fault code reader LED Mazda MX-5 mk1 & mk2 Eunos MX5 89-00 | eBay
As posted above, cars going back in tomorrow so hopefully all will get sorted. Was just checking the leads new and old and all nice and shiny inside except old lead No.2 which looks like it has little burnt residue at the bottom where the plug touches. Picture here: Dropbox - File Deleted - Simplify your life
The existing leads were nearly 9 years old so guessing this is just wear and they were working fine but good to change? I say that as from diagnosis on here cylinder No.2 is working, its No.4 thats not firing and No.3 cable at coil end showing a little sparking but only with the new lead not the old one.
Fingers crossed…
Yay! All sorted, car running is back to normal, and is great, I’d forgotten what it was supposed to be like! Ha ha! Life can go back to normal with less anxiety! It was as suggested no gap in the spark plug. Head tech was really embarrassed about how one of his mechanics left my car TWICE! Still need to speak to the Service manager again as he was not in today so will give a final update in a few days. Thanks again for all your help
Unbelievable, hope you get something back like a free service or something not that i would trust them if they can’t fit a spark plug properly.