Misfire Cause Found

Engines, Transmissions & Final Drive questions and answers

Moderators: timk, Stu, zombie, Andrew, The American, Lokiel, -alex, miata, StanTheMan, greenMachine, ManiacLachy, Daffy

davamb
Fast Driver
Posts: 230
Joined: Sun Jan 22, 2006 9:00 am
Vehicle: NA6
Location: Close to PI

Misfire Cause Found

Postby davamb » Sat Jan 29, 2011 9:26 pm

Been a while since I've spent any time or money on the old thing, now trying to make good with a new water pump (thanks Morris) yet to be fitted and some effort into chasing a misfire that's been steadily worsening.

Today I found the cause of the misfire and I'm really not best pleased, to put it mildly.
Have a look at this:
Image
Not long after I bought it I had new leads and cambelt fitted as I wasn't sure of the age of these parts. Now what the mechanic's done is used straight (instead of right-angle connectors) in the plug set and not pressed the metal inner home into the ignition coil pack on two pots. The plug shrouds are right-angle and straight connectors could certainly be used as has been done on the remaining two pots, but on the two that haven't - this is the result. The metal inner has been sitting at the top of the coil pack outer and the spark has just been jumping the gap or tracking the inside of the dielectric (more likely). Have a look at what it's done to the insulator - it was just dust! I am simply staggered that the car ran so long so well - phenomenal. Absolutely amazing.

What I don't know is if this was how the lead set was originally fitted or if it has been done in a subsequent service so I can't apportion blame. I'll see if I can build up the lost material with some epoxy compound or similar, but I feel the real solution is going to be a new coil pack.

So time to ask assistance of one and all - anyone got a decent second-hander sitting around in Melb??? Also anyone recommend a decent mechanic to replace the water pump - I just don't have the time or workspace at the moment. (Tony at FulTech doesn't seem to be answering his calls, maybe on hols?)

Thanks in advance.
Cheers, Dave, 1990 NA6
Via est vita.

User avatar
ak_perth
Fast Driver
Posts: 190
Joined: Tue Apr 06, 2010 7:18 pm
Vehicle: Clubman
Location: Perth, WA

Re: Misfire Cause Found

Postby ak_perth » Wed Feb 02, 2011 6:35 pm

Sorry to hear about your problems.

I burnt my coil pack out last autumn on my Clubman by leaving the ignition on by mistake.

I called MX5 Mania and they had a second-hand coil pack for my car in stock. The guaranteed it worked and i got it at a fraction of the price of a new one. Mazda dealers wanted $800 for a brand new one. Unbelievable price :shock:

Anyway it arrived after 3 days, very fast for Perth, and it works perfectly. So if you cant find a second hand one in Melbourne try MX5 Mania.

Cheers

AK

davamb
Fast Driver
Posts: 230
Joined: Sun Jan 22, 2006 9:00 am
Vehicle: NA6
Location: Close to PI

Re: Misfire Cause Found

Postby davamb » Thu Feb 03, 2011 10:01 am

Bought an old head with ignition pack attached off Entice a couple of nights ago and exchanged packs last night. All sorted. Big thanks to all who offered help.
Cheers, Dave, 1990 NA6
Via est vita.

User avatar
Entice
Fast Driver
Posts: 145
Joined: Tue Jun 17, 2003 11:00 am
Vehicle: NA6
Location: Melbourne
Contact:

Re: Misfire Cause Found

Postby Entice » Thu Feb 03, 2011 6:36 pm

good to hear all is fine! hope it runs better!
More opportunities have been lost from indecision, rather than wrong decision.


Return to “MX5 Engines, Transmission & Final Drive”

Who is online

Users browsing this forum: No registered users and 97 guests