[Miata] '02 Miata Bucking Without CEL - Big Mystery!

Tue May 27 07:34:56 CDT 2008

Still worth thinking about it

Does the cam cover appear to have been cleaned with some sort of cleaner
that might have removed a coating??

In my case new wires, even custom hi performance wires just didn't matter.
The way I finally found it was it was dark, the car wouldn't start, I had
the hood open and when it started I could see a blue glow under the hood.
It looked like St Elmo's Fire all over the engine.

Larry

White Knight      1991 Crystal White   #99 CSP
Silver Bullet        1992 Silverstone     #17 SM2  FM I+ Turbo
Honey B             1992 Sunburst Yellow #99 SM2L  JR Supercharger
Whooosh           2004 Titanium Mazdaspeed MX-5

LowCountry Miata   <http://www.lowcountrymiataclub.net>
http://www.lowcountrymiataclub.net
Masters Miata
RAGS 074

From: miata-bounces at realbig.com [mailto:miata-bounces at realbig.com] On Behalf
Of Bryan Wyatt
Sent: Tuesday, May 27, 2008 8:23 AM
To: 'Miata Mailing List'
Subject: Re: [Miata] '02 Miata Bucking Without CEL - Big Mystery!

Each time, it was 70-85deg F and humid but not raining.  Strangely enough,
it's been raining like crazy up here and the car's been just fine.  Each
time it's acted up, the weather's been generally "good" if not cloudy.

-Bryan

--- On Tue, 5/27/08, Larry Alster <Larry at Miata.net> wrote:

From: Larry Alster <Larry at Miata.net>
Subject: RE: [Miata] '02 Miata Bucking Without CEL - Big Mystery!
To: bryanewyatt at yahoo.com, "'Miata Mailing List'" <miata at realbig.com>
Date: Tuesday, May 27, 2008, 8:01 AM

Bryan

What was the weather like??  Was it raining or had it been raining before
this happened??  I used to have an issue with my Toyota in the 70?s where
whenever it was wet or humid I lost cylinders and it didn?t want to restart.
The problem ended up being that the factory clear coating on the cam cover
had failed and I was getting an arc over from the wires to the cam cover
whenever it was humid.  Painting the cam cover with engine paint solved the
problem.

Larry

White Knight      1991 Crystal White   #99 CSP
Silver Bullet        1992 Silverstone     #17 SM2  FM I+ Turbo
Honey B             1992 Sunburst Yellow #99 SM2L  JR Supercharger
Whooosh           2004 Titanium Mazdaspeed MX-5

LowCountry Miata   <http://www.lowcountrymiataclub.net/>
http://www.lowcountrymiataclub.net
Masters Miata
RAGS 074

From: miata-bounces at realbig.com [mailto:miata-bounces at realbig.com] On Behalf
Of Bryan Wyatt
Sent: Tuesday, May 27, 2008 7:44 AM
To: Miata Mailing List
Subject: Re: [Miata] '02 Miata Bucking Without CEL - Big Mystery!

I've been thinking of changing the wires to Magnacores anyway, so this might
be an excuse.  They seem to cost almost twice as much as the old reliable
NGK Blues, though.  Everyone I've talked to says they're worth it, but I'm a
little skeptical.

As hot as my car seems to be (seriously, I don't remember Junior getting
this hot), the exposed wires near the harness points just seems like an all
too likely candidate for shorting out at high temps.

You had an experience like this one, Mark?  Was there anything different
about it?

-Bryan

--- On Tue, 5/27/08, mark moore <miata at bwr.eastlink.ca> wrote:

From: mark moore <miata at bwr.eastlink.ca>
Subject: Re: [Miata] '02 Miata Bucking Without CEL - Big Mystery!
To: "Bryan Wyatt" <bryanewyatt at yahoo.com>
Date: Tuesday, May 27, 2008, 5:33 AM

Bryan for what it's worth the wires can fail. I have had to replace the OEM
set and a set of the RB Ultras. We have a lot more miles on our car though.
We had an issue somewhat like yours when we were a long way from home
(southern US) and it scared the wits out of me as it happened on the highway
in traffic. We made it back home to Canada with the issue reoccurring only
once I believe. In our case it was the wires and a very occasional thing.

I don't recall the exact circumstances at the time but don't rule them out
as a potential cause. Maybe consider all the other advice first and get new
ones if you have to. NGK make them now and the price is reasonable. I
haven't heard of coils on an 01+ being a problem.

One other odd thing we had happen to a club member was the immobilizer in
the key causing the car to shut down but then it could be restarted. Again
an erratic thing. That one took the owner about six months to track down and
correct!

Mark

My car is an '02, which means that I don't have coil packs--just the coils
on plugs 2 and 4.  I checked the wires and ensured that they locked in place
both at the coils and on top of the plugs.

As for wires, I was under the impression that 01+ wires seldom need
replacing.  How about the coils?  That's $235 or so to replace 4 parts!

-Bryan

--- On Mon, 5/26/08, Hank <Subhunter at verizon.net> wrote:

Don't know about your year car but plug wires going bad at around 20 -
25Kmiles regardless of appearance is a very common problem common to Miatas
and when they go bad you get some strange indications.  Those that you
mention aren't out of the ball park.  Also possible that you've cracked the
insulator on a plug or that for some other reason one of them's shorting out
under heat.  Other then that there's always a possibility of an electrical
short under the hood due to heat and vibration, give all the plugs and
wiring under the bonnet a good physical check for security seems in order. 

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