[Miata] '02 Miata Bucking Without CEL - Big Mystery!
Keith Tanner
keith at miata.net
Tue May 27 10:33:41 CDT 2008
Does anything else happen at the same time? What does the tach do?
I'm thinking electrical, and if the tach is freaking out (probably
bouncing from the current RPM to 0 and back) then you're losing power
to the ECU.
I've seen an old Land Rover do this with a broken motor mount, but
that's because it had a mechanical throttle linkage and when the
engine moved over, it would change the throttle position :) But I've
also seen engine movement pull ground wires free, until the engine
loses power, then it moves back and the ground reconnects, so you get
power back, so the engine moves and pulls the ground wire free....
Keith
On Tue, May 27, 2008 at 9:12 AM, Bryan Wyatt <bryanewyatt at yahoo.com> wrote:
> It does come on at startup, but goes away as soon as the car fires (or at
> least whenever it normally does when nothing's wrong).
>
> I'm out of warranty...sounds expensive (I realize what they're suggesting is
> replacement of the ECU).
>
> -Bryan
>
> --- On Tue, 5/27/08, Matt Yates <m at y8s.com> wrote:
>
> From: Matt Yates <m at y8s.com>
> Subject: RE: '02 Miata Bucking Without CEL - Big Mystery!
> To: bryanewyatt at yahoo.com
> Cc: "'Miata Power List'" <miatapower at miatapower.net>, "'Miata Mailing List'"
> <miata at realbig.com>
> Date: Tuesday, May 27, 2008, 11:09 AM
>
> I know you say no MIL
> but...
> http://www.finishlineperformance.com/pdf/miata/bulletin/01-025-06-1648.pdf
>
> and you did verify that the MIL comes on at startup right?
>
>> 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
>> 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: Bryan Wyatt
>>
>> To: Miata Power List ; 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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>>
>>
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>
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