Car problem

July 10, 2006 6:44 AM

Auto Mechanic Filter: What is preventing my car from starting? Happens about every 10th time I attempt to start. No click, no churn, but the lights (including those on the dashboard) work fine as does the radio. I get it going by rocking the front end of the car up and down, and back and forth for a few seconds. Head back in, turn the key and it starts normally.

Some additional background: Car is 11 years old, the problem began after the engine was replaced last fall. Numerous trips to the mechanic have turned up nothing -- battery is good, alternator is good and all wiring seems firmly in place. Someone recently suggested shifting to neutral the next time it happens and, if it starts, that would indicate a bad "neutral saftey switch." It just happened again, but I was unable to start the car in neutral. Rocking is the only thing that works.

This is driving me nuts. Any suggestions greatly appreciated.

posted by terrier319 to home & garden (19 comments total)

Are you sure there's no click whatsoever? It sounds like a sticking starter motor.
posted by derbs at 6:47 AM on July 10, 2006

Sounds like the flywheel that is engaged by your starter might have some broken teeth in it.

The exact same symptoms were manifesting on an older car I used to own. And rocking was my solution as well. The rocking moved the flywheel enough so that unbroken teeth were engaged by the starter's gear.

So my guess is either the starter or the flywheel needs to be replaced.
posted by lyam at 6:49 AM on July 10, 2006

Maybe you need to find a new mechanic. The symptoms that you describe would send most good mechanics to look at the starter, flywheel and starter relay right away. Hopefully it's the starter and not the flywheel which would be a lot more expensive fix.
posted by octothorpe at 6:56 AM on July 10, 2006

Sounds to me like you might have a GM product (make, model, engine and transmission type are useful pieces of information to include for these kinds of questions) and disk in the solenoid has a dead spot. Replace solenoid or starter unit to repair. You can test by shorting the solenoid with a screwdriver when the symptom appears.
posted by Mitheral at 6:57 AM on July 10, 2006

I'd rule out one big possibility by using a wire brush tool on the battery posts and cables. It only takes a minute or two and is a preventative maintenance item anyway (they make $4 brushes at the auto parts store for just this thing). Battery corrosion is a major source of weird electrical problems.
posted by rolypolyman at 6:58 AM on July 10, 2006

Try reading this FAQ about starting problems. I'd think it's your starter/solenoid. I also recall hearing the car guys suggesting that in circumstances like this, you give the starter motor housing a whack with a hammer, which is probably doing what rocking does for you in more prejudicial manner.
posted by plinth at 7:28 AM on July 10, 2006

In fact, in reading a bunch of pages returned by searching for "starter motor hammer", this is a common diagnostic technique.

Here is a decent link on testing the whole assembly.
posted by plinth at 7:31 AM on July 10, 2006

Thanks all - this is great info - and especially Plinth for the links. I have no desire to leave this to a guessing game by the mechanics (been there already) and this gives me the info I need to zero in on the likely cause. Peace.
posted by terrier319 at 7:59 AM on July 10, 2006

I, personally, would bet you have an either loose, or corroded wire, on either the starter motor or (if it's separate) the starter solenoid (which is actually a relay).

Don't forget to let us know. :-)
posted by baylink at 9:39 AM on July 10, 2006

I second the idea of cleaning the battery posts. If that's the problem, it's a cheap fix.
posted by DieHipsterDie at 9:49 AM on July 10, 2006

None of the above indicates ruling out the neutral safety switch as the cause. The switch is designed to prevent starting the car in gear and possibly injuring someone. The "shifting to neutral" advice doesn't make sense to me. If the switch is working properly, the car will start only in Park and Neutral. If the switch is stuck in the on position, the car will start in any gear, which is dangerous. If the switch is stuck in the off position, the car won't start in any gear, which is your problem.
posted by weapons-grade pandemonium at 10:35 AM on July 10, 2006

The neutral switch is on the transmission, so rocking the car to fix the problem also points in that direction.
posted by weapons-grade pandemonium at 10:38 AM on July 10, 2006

Or a bad ground wire. Rocking the boat may be enough to make the connection.
posted by Gungho at 11:00 AM on July 10, 2006

Except that the lights work, suggesting it is not the ground wire.
posted by weapons-grade pandemonium at 12:07 PM on July 10, 2006

plinth may be right: i've successfully used a 'starter hammer' on my car. this is not uncommon for nissan/infiniti's, i am told. a few taps and it would start just fine.

as explained to me by a friendly mechanic, starters get bad spots in them that don't conduct electricity. if the starter stops (from previous start) on a bad spot, it won't start the next time. tapping it with a hammer is enough to move it to a working position.

over a month's time the problem became more frequent and hammering became less effective, so i replaced the starter. if you become convinced it's the starter, i'd suggest keeping an eye on e-bay and getting a deal on a replacement before this one totally quits.
posted by mdpc98 at 12:20 PM on July 10, 2006

I just had a similar problem, and shifting out of park and back seems to fix the problem for me. You could try that.
posted by exceptinsects at 12:47 PM on July 10, 2006

Oh, thanks, Gung Ho: now I'm going to have The Hues Corporation in my head all night long.
posted by baylink at 1:06 PM on July 10, 2006

Most likely it is the battery connections. Check and wire brush the corrosion and check the leads to make sure there is no damage to them. They could also be shorting on something when you close the hood.
posted by JJ86 at 2:06 PM on July 10, 2006

so it sounds like I should start with the least expensive check -- the battery cables -- and then go up from there, checking the solenoid, the neutral safety switch, the starter and then the flywheel. I'm pissed because this problem was non-existent until the engine was replaced, which tells me the mechanic who did the job did a poor job of hooking things back up, or maybe not.

Thanks again, all, for the input.
posted by terrier319 at 2:36 PM on July 10, 2006