NA not running on all 4, help!

[TREMAiNE]

Thread was also in GG but has been moved to MX5 forum... So now it shows twice!

MX-5 is playing up!

Was running absolutely fine then suddenly started running really lump, massive dip in power (not that it had much in the first place hehe). Sounds like its not firing on all 4.


Here is a video of it on idle - the sound is more clear from the exhaust than filming the engine directly.

https://www.youtube.com/watch?v=5S3Vcrvskfc


Here is a video of it on idle in the cabin, whenever I filmed it wasn't too bad, whenever I stopped it would dip right down almost at 0 revs!

https://www.youtube.com/watch?v=xdGzOUpHnH4


Here is a video of it accelerating, in 2nd, 3rd and 4th from 2,000rpm.

https://www.youtube.com/watch?v=jheiJHTwSdo



The plugs were changed last year, so I can't see it being them. We (my friend and I) were guessing HT Leads and/or Coil Pack - but in reality don't even know what the problem is so that's a guess really.

Any suggestions?

Cheers.

Edited by TREMAiNE on Thursday 3rd March 11:46

[Oldandslow]

First I'd check the HT lead connections just incase one has worked loose or the plug contact has unscrewed. Probably also inspect plugs and check gaps. If all looks good HT leads or coil pack could be knackered. HT leads are much cheaper and easier to replace so I'd try those first.

[elephantstone]

I had this problem on my old mk2, was coil pack.

[pewe]

If the above fail to cure it I'd be looking at the Cam Position Sensor (CPS) located at the back of the inlet cam box.
Be aware though that new ones are expensive @ c.£200+, though if it's a 1.6 Autolink have a seconhand one for c.£40.
Worth fitting a new O ring whilst you're at it.
HTH.
Cheers, Pewe.

[TREMAiNE]

Cheers for the replies guys.

I have new HT leads and Coil Pack arriving in the post this afternoon so will give that a try.

I am useless when it comes to this stuff, I can do the leads but that is it. A friend will do the Coil Pack at the weekend for me. Hopefully that solves it.

[TREMAiNE]

UPDATE

It was the HT leads after all. Not only has it fixed the problem but the car is running even smoother now than before.

I'll send the Coil Pack back as that's not needed and I think I'll tread the car to a new soft top now as the old one has a massive tear in it where I stupidly tried to open it at 50mp

[pewe]

Glad to hear it's fixed.
Depending on where you are give Jack Smith Trimmers in Swansea a call.
I went down from Reading for the day, had a nice walk along the beach and a bite of lunch in an Italian restaurant before picking it up.
They do a cracking job and their prices are very good.
HTH.
Cheers, Pewe

[Digby]

Almost everyone I knew in MX-5 circles ran uprated HT leads. They seem to like wearing out the standard ones quite quickly.