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Intermittent starting problem 2005 Mazda3 80k miles

I’m the 2d owner of an '05 Mazda3 5spd with 80k miles. About 5 times in the 3 years I’ve owned it the car hasn’t started. 3 of those times were the following scenario: after an hour of highway driving I stop at McDonald’s to grab a sausage egg McMuffin. The car is off for the 90 seconds it takes for me to get it, and when I turn the key the engine turns over but doesn’t start. I try turning it maybe one or two dozen times over ten minutes and eventually it starts. Then I have a check engine light for the rest of the day that goes away on its own. Plenty of gas in the tank.

Once this same situation happened after driving for about 15 minutes in the city and after 15 minutes of sitting cold. That time I called a tow truck, waited around for an hour, and by the time the tow arrived he could start the car by leaning on the gas and cranking the starter for about 20 seconds.

The other day I came out in the morning after the car had been sitting for 2 days and this time the starter turned really fast with a high-pitched squeal. I thought that the starter must not be engaged to the engine. I took a car share car to work and the next morning tried it again, still fast starter and no start. Tow truck took it to the mechanic, who said ‘bad news, it looks like your timing belt is gone and you have no compression’. I was surprised, 80k miles seems a little early for that, but OK. So later that day he calls and says it started right up!

So I said ‘that shows that it couldn’t have been low compression, how could the compression come back? It must be that the starter wasn’t engaging the flywheel’. And he says no, he looked in the oil cap and when the starter motor was spinning fast he saw the engine turning. He went on to suggest that I put in high-octane gasoline and that there wasn’t anything to be done about it, leaving me doubly skeptical.

So what’s the deal? Is this cylinder wash down like I’ve read on other posts here? A crazy mechanic who can’t recognize a starter motor problem? It’s hard to diagnose now, because the car runs fine. And I’m afraid I can’t remember any other particular clicks or hums while it was having the problem.

Well, one thing for sure is that putting high-octane gas in the tank is not going to fix the problem with this car. In fact, I would be VERY distrustful of any mechanic who believes that high-octane gas will cure anything besides pinging or pre-ignition.

If the engine was turning over unusually fast, that would be a possible indicator of a timing belt that snapped. However, timing belts do not resurrect themselves, so a broken timing belt should be ruled out.

Truthfully, I think that the problem could be something as simple as a leaking fuel injector that is causing too much fuel to be dumped into one or more of the cylinders. When a hot re-start is problematic, it frequently points toward a leaking fuel injector or a bad fuel pressure regulator. In fact, the way that the tow truck driver was able to start the engine is indicative of a leaking fuel injector, and possibly a bad fuel pressure regulator.

If I were you, I would not return to the mechanic who recommended high-octane gas. Use the Mechanic’s Files on this site to locate recommended independent mechanics in your area, or ask friends, neighbors, relatives, and co-workers for a recommended indy mechanic. AVOID Midas, Meineke, Monro, Sears, Pep Boys, AAMCO, and other chains!

And, don’t forget to have that timing belt replaced when it is due–which should be in approximately 2 years or when you reach 105k miles, whichever comes first.