Miata won`t start

Lanny Chambers wrote:
> In article >,
> (Leon van Dommelen) wrote:
>
>
>>Maybe the spark generation mechanism needs a minimum voltage,
>>more than a minimum amperage.
>
>
> There's also probably some voltage below which the ECU won't boot.

I don't know which specific parts are in the Mazda ECUs,
but historically, 5V logic has been used and there's usually
a voltage regulator which requires something 1 to 2V greater
for proper operation.

Many years ago, I built a digital ignition controller
for my Honda VF1100S, and I used common three-pin 5V
regular (7805-type). The controller was sometimes
flakey if the battery slightly weak. The regulator
required a minimum of 7V to properly regulate and the
battery voltage would sometimes drop below this during
cold-cranking.

So I replaced the regulator with a low-dropout device,
which worked fine down to an input voltage of 5.6V - and
it completely solved the problem.

Slightly amusing is that I later was comparing notes with
the lead engineer at Vance and Hines Racing, they had a
digital ignition controller that turned out to be very
similar to mine (only so many ways to skin a cat). I
asked which low-dropout regulator they were using, and
was told that they had a problem with low batteries.
So I suggested the part I used, and they switched to it.

That actually prompted an offer of a job - but, alas, I did
not follow my motorsports heart into a career... a year or
two earlier and I might have.

On a side note, Happy Thanksgiving to those that celebrate
the day.

Dana

Hi: Abour 5 months ago my '01 had same symtoms, a trip to the dealer
and a new fuel pump fixed it. At 18,600 miles miata agreed to cover
the cost of the pump, I paid labor only. Miata guarantees pump for 12
months/ 12k miles. Autozone pump half price and lifetime guarantee.

good luck.. Wes


On 19 Nov 2004 17:55:13 GMT,
(AuctionsByGeorge) wrote:

>2001 Mazda Miata SE
>
>Hi ,
>We drove it 3 days ago , no problems. Went to take it for a drive today ,
>engine turns over , radio & electrical items are working but engine won`t
>start. Am clueless when it comes to cars. Father in law says might be fuel pump
>but he knows about as much about cars as I do. It has been raining on & off for
>the last 2 days but has been under the carport during that time. Any ideas
>where to start ? Thanks in advance. George in Arkansas