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

Tue May 27 06:15:56 CDT 2008

It might pay to get an OBDII scanner that can log and drive around with it
for when  the problem starts and see if you can find anything.

I use this unit    <http://obddiagnostics.com/> http://obddiagnostics.com/

You do need a laptop but you can set it up to log and you can also run it so
all the functions are being shown on the screen at the same time so you can
see the data real-time.

Bill could this somehow be TPS related since he says it only happens at
partial throttle??

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: miatapower-bounces at miatapower.net
[mailto:miatapower-bounces at miatapower.net] On Behalf Of Bryan Wyatt
Sent: Tuesday, May 27, 2008 7:05 AM
To: 'Miata Power List'; 'Miata Mailing List'
Subject: RE: '02 Miata Bucking Without CEL - Big Mystery!

I was thinking the same.  Knowing my luck, I could take it to the shop and
probably have nothing happen...or it could happen on my way home.  

You know?  I went through crap like this with the old car (spent several
months and a couple grand--probably--chasing down P0300's that never
entirely went away).  I'm beginning to suspect that I just might be
cursed...

-Bryan

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

From: Larry Alster <Larry at Miata.net>
Subject: RE: '02 Miata Bucking Without CEL - Big Mystery!
To: bryanewyatt at yahoo.com, "'Miata Power List'" <miatapower at miatapower.net>,
"'Miata Mailing List'" <miata at realbig.com>
Date: Tuesday, May 27, 2008, 6:13 AM

I think I might discount the condensation thinking since you said this has
happened before over 1000 miles ago.  Seems unlikely to me that the water
laid around happily in the tank for over 1000 miles before acting up again.
Something that intermittent sounds more electrical to me.

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: miatapower-bounces at miatapower.net
[mailto:miatapower-bounces at miatapower.net] On Behalf Of Bryan Wyatt
Sent: Monday, May 26, 2008 9:53 PM
To: Miata Power List; Miata Mailing List
Subject: Re: '02 Miata Bucking Without CEL - Big Mystery!

It's worth noting that this happened with the tank about 1/2 to 3/4 full.
Is there any way to clear out the condensation?  Some sort of alcohol-based
solution?

-Bryan

--- On Mon, 5/26/08, Ray Ayala <ayala.ray at gmail.com> wrote:

From: Ray Ayala <ayala.ray at gmail.com>
Subject: Re: '02 Miata Bucking Without CEL - Big Mystery!
To: bryanewyatt at yahoo.com, "Miata Power List" <miatapower at miatapower.net>,
"Miata Mailing List" <miata at realbig.com>
Date: Monday, May 26, 2008, 9:42 PM

My dad had that happen once and it turned out to be condensation in the fuel
tank.  Apparently a few small puddles of water will drift around on the
bottom of the tank and part of one will occasionally get sucked up by the
fuel pump.

----- Original Message ----- 

From:  <mailto:bryanewyatt at yahoo.com> Bryan Wyatt 

To:  <mailto:miatapower at miatapower.net> Miata Power List ;
<mailto:miata at realbig.com> Miata Mailing List 

Sent: Monday, May 26, 2008 4:41 PM

Subject: '02 Miata Bucking Without CEL - Big Mystery!

All,

I'm not sure how to describe this in one word, but here goes the long
version:

I was on my way home driving across Ohio this weekend and 3 separate times
the car (an '02 with stock everything intake/exhaust/ignition and about 60k
on the clock) began to buck uncontrollably.  The revs would bounce within a
500rpm range of whatever value they were at when the car began to buck.  The
only way to "cure" the problem was to turn the car off and wait for it to
cool down.  Unforutnately, the car didn't always start on the first try.
Very frustrating!

As I said before, the car is stock everything (I even put on a stock exhaust
after I bought it).  I replaced the plugs about a month (and 1000mi) ago,
but the car did this same thing on the old plugs.  It will even repeat the
behavoir at random in the parking lot at work driving at no more than 25mph.

Any ideas?  Could heat soak be affecting the coils or wires?  Maybe even the
Cam Angle Sensor?  The car seems to start up after I let the engine cool.
Is there a way I could effectively cool off the engine bay?

To repeat one last time...the car does not throw a CEL even after the car is
restarted.

Thanks for your help!

-Bryan and The Tick

  _____  

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