Misfiring? Solutions

Forshaw · Postby **Forshaw** » Sun Jul 28, 2013 2:15 pm

So heres the problem I encountered, hoping that someone in the future with the same issue is able to benefit from this thread.

So my car is burbling/ gurgling sound, basically misfiring taking off in first (driving normally) inspecting under the hood and headers feel quite hot, everything else is below normal temp, drove for like 2 minutes (from work, just stopped in a car park roughly 1km from where it was sitting at work.

After waiting roughly 10 minutes, I continued to drive home and the problem got worse, constantly misfiring basically sounding like a tractor (no joke). So I left it in a safe spot over night and called family for a ride home.

Made a few phonecalls last night and browsed the forum to come to the conclusion that it could have possibly been the following; core pack, spark leads, spark plugs, fuel filter (bad fuel etc).

So this morning I start firstly by inspecting those, core pack was fine (visually), leads were fine, so I ended up buying some new spark plugs (honestly my hopes weren't high, but I wanted to put them in before I spent $70 on a fuel filter.

ImageUploadedByTapatalk1374981500.687325.jpg

I pulled out my first plug and it was shocking, when I saw this my hopes of driving home today increased by 300%.
Replaced all 4 and it was driving flawlessly!

Thankfully I checked the cheapest option first this morning and turned out to be the fix, thanks to NitroDan and Pham for allowing me to harass them at 8:00pm last night!

hks_kansei · Postby **hks_kansei** » Sun Jul 28, 2013 2:23 pm

It might not be the end of it, my car started doing similar for a while.

New plugs fixed it, but all they did was slow down the problem (being running a bit too rich and fouling plugs)

On my car a new set of leads and a new o2 sensor fixed the issue (leads were old and not 100% anymore, so haivng trouble getting spark) and the o2 sensor meant that it was running stupidly rich.

Forshaw · Postby **Forshaw** » Sun Jul 28, 2013 2:32 pm

I believe it is running a little rich, possibly worth getting that replaced regardless, thanks mate!

mx-593 · Postby **mx-593** » Tue Jul 30, 2013 1:29 am

I think I'm in the same situation, half a tank of 98 fuel goes in about 2 days...
Could anyone suggest a solution to my problem ?

93_Clubman · Postby **93_Clubman** » Tue Jul 30, 2013 10:53 am

Forshaw wrote:I believe it is running a little rich, possibly worth getting that replaced regardless, thanks mate!

NA6 normally runs a bit rich, but depending on if/when if O2 sensor has been replaced you may see some benefit.

Good to hear new plugs helped, but like hks I'd say it wasn't the underlying cause. NA6 coil pack are a weakness, which sometimes shows as pitting or burning inside the coil pack posts where the plug leads fit. Also, if plug leads not relatively recently replaced they would be worth doing.

93_Clubman · Postby **93_Clubman** » Tue Jul 30, 2013 10:57 am

mx-593 wrote:I think I'm in the same situation, half a tank of 98 fuel goes in about 2 days...
Could anyone suggest a solution to my problem ?

If not done recently, baseline (major) service the car, so that you know the basics are right to begin with. Then, as the say, if the problem persists you can troubleshoot it more easily due to the narrower field of options.

marty085 · Postby **marty085** » Tue Jul 30, 2013 1:25 pm

Would u blokes reckon there's any benefit to getting any particular brand of aftermarket spark plug leads over the genuine Mazda spark plug leads? The gen Mazda (OEM) leads are slightly cheaper ($70) at mania. Repco just quoted me $165 for Top Gun leads which is a hell of a lot even with my NRMA 10% discount.

Postby **NitroDann** » Tue Jul 30, 2013 2:51 pm

The plugs are a sign of something else wrong, albeit minor.

Id still be looking around to find the rich condition.

Dann

Forshaw · Postby **Forshaw** » Tue Jul 30, 2013 8:22 pm

Plugs seem to have only temporarily fixed this issue, looking further into the issue, didn't notice any corrosion on the coil pack but still could possibly be that.

Can anyone tell me if Timing might possibly be the issue? I can't confirm the timing belt has been done (car currently at 145xxx (bought it at the dealership at 136xxx).

corners · Postby **corners** » Wed Jul 31, 2013 10:31 am

Timing, hmm maybe but not when the plugs look like that.
If its an NA6 there is a coolant sensor on the back of the head that the ECU uses for cold start, that could be playing up in turn keeping the ECU in cold start mode = super rich.

Otherwise you could try and connect an LED to the diagnostic connector to see if it generates any codes

http://www.miata.net/garage/Engine_Diagnostics.html

93_Clubman · Postby **93_Clubman** » Wed Jul 31, 2013 11:52 am

marty085 wrote:Would u blokes reckon there's any benefit to getting any particular brand of aftermarket spark plug leads over the genuine Mazda spark plug leads? The gen Mazda (OEM) leads are slightly cheaper ($70) at mania. Repco just quoted me $165 for Top Gun leads which is a hell of a lot even with my NRMA 10% discount.

Personally I'd go to a performance ignition workshop, like http://www.performanceignition.com.au in Melb, & get them to make you up a set for a lot less cost, or if time poor then buy Magnecor over Top Gun, as my Magnecors have lasted 13 years so far. However, NGK leads also seem to be popular & more economical option.

Forshaw · Postby **Forshaw** » Wed Jul 31, 2013 12:23 pm

Minor update;
Leads will be replaced Monday (leaving it in the garage until then)
I actually washed my car the day it had started but I highly doubt water had made its way into the engine bay, but I'm going to use an air compressor to try get rid of some possible moisture tonight.

If problem persists, plans are then o2 sensor (most likely doing this anyway because it seems to be running a little rich?)
Then worse case scenario, coil pack