mx5cartalk.com

hi all
well my first non run issued started today. kicked over the car and everthing was fine but once out the driveway and on the road the car bogged down and started missing badly. had no choice but point in back home and in the garage.
following that i

1. checked the dash -no check engine light on.
2. out with the scanner - no codes stored.
3. did a vacum check 18 on idle like always and a good rev sent it to 21 plus.

appears to be having the rough idle engine shake issue just on applying gas pedal pressure. last time i drove it everthing was fine. below is a video i shot which may help with some answers.
thanks in advance

http://www.youtube.com/watch?feature=pl ... 0IOwMRp6tc

Had to really tell from the video. I'd start with the simple things like the AFM, any MX-5 mates around Orange than you can swap across parts and see what solves the issue?

Could be fuel pump, or coil pack, but agree hard to just diagnose like that

Sounds like a fouled plug.

Take the plugs out and clean/replace.
Chances are one will come out wet (fuel fouled)


if it runs with new plugs, then it's time to check why they are fouling, could be leads, coil, or could be o2 sensor.

One my car it was a combination of degraded leads, and a buggered o2 sensor that caused a similar issue.
Leads meant spark wasn't as strong as it could have been, and the o2 was not working right causing the ECU to run too rich.

result = fouled plugs.

Im having a very similar problem with my se also, its taken ages to figure it out. Is it so bad that the car isnt drive able? How many km's has it done?

heres a photo of the plug removed closest to the fan. car has 61,000klm what plugs would be recommend for an se with a few mods or just stay with these denso's

May be the angle of pic, but is the electrode missing?

White deposits noramlly mean runnjing a bit leaqn, or the wrong plugs. (either colder or gotter, cant; rememebr which)

Apologies for spelling, been drinkgn hevaily.

didn't take much notice -will check it out tomorrow...

New plugs wouldn't hurt. I'd be getting NGK and looks like they recommend IFR5T-8N
NGK website

From the photo I would say it is running rich. A light brown colour is what you are looking for.

http://www.autocorner.ca/pages/sparkplugs.html

I used to tune my two stroke motor bike by plug readings. I was taught by an old school bike builder many years ago.

Magpie wrote:From the photo I would say it is running rich. A light brown colour is what you are looking for.

ideally yes, but MX5's generally (granted, non turbo) tend to run a bit rich as factory.

So a dry blackish is normal (again, for non tubs)

Whilst mine is not stock the plugs are a nice brown. However most cars are tuned to run a little rich, the question is, is the black stuff wet or dry.

i ordered the plugs and leads today so will try that out first

plugs and leads arrived today and fitted. once kicked over it appears fine but will take it out for a run later. one thing i did notice is the connector to the front coil would not clip and lock into position.
still wont do it so i might have to get an auto election to fix that one