Miata won`t start

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
Reply to
AuctionsByGeorge
Loading thread data ...

Okay, my first guess - plug wires.

Ignition module?

Steve McMahon Green JRSC '00LS

Reply to
McMahon

Can be anything if you ask me. Starting with the battery not being able to rotate the engine at enough speed. Check for a spark. I would go to an auto parts store and get a Haynes manual and a ignition tester.

Leon

Reply to
Leon van Dommelen

My ca is an LS 6 speed. I had exactly the same problem. I checked "everything" - I thought! Had to have the car towed to miata dealer. Took them a day to locate the problem. Wires were chewed by some type of rodent, probably a fruit rat or Possum. I didn't believe the mechanic but there was "certain" evidence of the "beast in the engihne compartment. Guess is was warm and comfy in there. Anyway, cost to fix was $250!

Not to have it happen again, I placed traps and rat bait in appropriate places. Kept the dog away during the next couple of weeks. No more problems!

Reply to
bluemiata

Maybe you just need a better dog.

Reply to
Joe

Reply to
junktin

Werid. Generating the spark requires no power at all compared to what it takes to crank.

Reply to
Grant Edwards

Maybe the spark generation mechanism needs a minimum voltage, more than a minimum amperage. I thought it was the lack of speed, but it could be an ignition problem. I know from experience it does not start below a certain battery power, though it turns over. Why voltage would be so critical I would not know.

With points, I guess they could not be disconnecting quickly enough. With an electronic ignition, I am not clear how the high voltage is generated in the first place.

Leon

Reply to
Leon van Dommelen

Same methodology. You have a coil with a primary/secondary. Earlier miatas had a separate transistor circuit that powered/depowered the primary to generate the spark. Later ones from 94-97 integrated the transitors into the coil. I have no idea how the newest ones do it, as I see some of the later cars mount coils right on top of the spark plugs.

Now you might have ebough voltage to turn the started, but it might be below the minimum needed to power the computer that generates the signals to excite the transistors driving the coils.

Reply to
L. Santer

There's also probably some voltage below which the ECU won't boot.

Reply to
Lanny Chambers

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

Reply to
Dana H. Myers

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

Reply to
Head Hoser

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.