Engine vibration

Technical Area Engine, Transmission, Exhaust etc
1

  1. My model of MX-5 is: nd mk1

  2. I’m based near: Twickenham

  3. I’m looking for technical help or recommendations on: engine vibration

2

Hi everyone, lve be enjoying my nd1 for 18 months now, and I’ve just started to encounter an annoying vibration . I changed the plugs , no joy . Had a full service, nofaults found. Garage said use premium petrol and it should clear mmm. Anyone had the same issue or any advice welcome.
Thanks.

3

You could do with having it scanned for misfire codes, noting them and clearing them out and waiting for it to happen again. Assuming it’s not old petrol that has been in there a long time.

If it’s a pronounced vibration that is either all the time or can be intermittent, the engine shakes and the car sounds vaguely like a subaru from the exhaust when it does there’s a good chance a coil pack may have failed, but this should normally be accompanied by a misfire code on any obd car which a mechanic can pull with a scanner. If it does it again you could always pull over and lift the bonnet then unplug the coil packs one by one. Each good one you unplug will make it run even worse, if there is one that you unplug that changes nothing you can suspect that’s the one at fault. Then it’s a case of marking it and moving it to another cylinder, then waiting for it to happen again and confirming it’s the same one at fault.

Bear in mind some cars require you to turn the car off after this test and restart to get that cylinder firing again.

Other things to check are dirty or failing plugs (which you’ve already done, assuming they’re correct type and gapped correctly), dirty air flow meter element, dirty throttle body plate and poor servicing but doesn’t sound like the last one if you look after your car.

Just a few suggestions. There are other things it could be on any car but these are some usual culprits for rough running :+1:.

4

Engine mount?

5

Thanks for your replies gents. I will get the mounts inspected.
When l had the service there was no fault codes showing, the garage made point of showing me the two plug in fault finders.
They said that this eliminated faulty plugs and coils. I thought maybe dirty injector , so l ve added cleaner to the fuel, given it a blast up to three figures, l mean seventy (top down of course) and it didn’t miss a beat. Gonna give it a longer run and see if clears it . Thanks again for your input, appreciated.