Help me start my jeep

July 17, 2009 8:56 AM

Help me start my car engine. Or at least understand why it won't start.

So: I went to start my car last night (2001 Jeep Wrangler), but flubbed it and let go of the key too soon; the engine turned over once but didn't start. When I tried again, it just made a single quiet click and didn't even try to turn over. Leaving it to sit overnight failed to magically solve the problem, which had been my fervent hope.

I've checked the obvious stuff -- the battery seems to have adequate charge; I tried jumpstarting it anyway and that didn't help either. That exhausts the full extent of my car repair ability.

I know the answer is probably going to be "call a tow truck", but I guess I'm hoping that there's some obvious cause-and-effect going on with the flubbed start, which will have an equally obvious solution... any ideas?

posted by ook to travel & transportation (31 comments total)

How did you determine that the battery has adequate charge?
Starter motor/solenoid is next. You can sometimes hit it (pole and hammer) and get started, but it sounds like it's on the way out.
posted by weapons-grade pandemonium at 8:59 AM on July 17

Try tapping (lightly) the starter motor with a hammer. I think it probably has floating brushes and worn brushes can get stuck in a position where they don't make contact.
posted by wigner3j at 9:01 AM on July 17

I'm not an expert but in my experience clicking means it's not getting a charge. This could be dead battery (jumping would work) or could also be a loose connection or corrosion around the battery terminals.

Failing those you get to weapons-grade's issues.
posted by bitdamaged at 9:02 AM on July 17

3rd'ing checking the battery.

My car died last week while I was at a gas station. I didn't think it was the battery because my lights and radio and wipers all worked when the engine was off. And it had just been working fine minutes before.

Turns out the battery was really weak after all. Engine started on the first try once we had hooked it up for a jump. I learned my lesson.
posted by mrsshotglass at 9:06 AM on July 17

My money is on the soleniod. Or the ignition coil.
posted by Danf at 9:07 AM on July 17

How did you determine that the battery has adequate charge?

Voltmeter (and the dashboard gauge) reads 12.5 volts.

Is the starter on a jeep close to the ground on the passenger side? (I googled for photos, but I'm not entirely sure I know what I'm looking for.) And by hit it with a hammer, do you literally mean hit it with a hammer? Because that's the sort of repair technique I'm pretty good at.

(How hard? Like tap tap tap, or angry hard?)
posted by ook at 9:07 AM on July 17

If the battery and cables are fine, then the problem is likely to be the starter motor itself. A jumpstart that did not help means that the battery is not the issue.

If you replace the starter motor, be aware that many people have complained about poor performance in aftermarket and rebuilt motors. Look for a warranty, or a shop that cares about their part sources.
posted by Midnight Skulker at 9:10 AM on July 17

No, take a small hammer or an open-end wrench and tap it gently for about 5 minutes. Don't bang the fuck out of it. I had a mechanic show me this trick (he said my starter was "oil soaked" as a leak was dripping right onto it), and it worked. The vehicle started right up.

I'm not saying this is your issue, but what I'm saying is that you want to imagine that there's crap in the starter that you want to dislodge internally. Tap like that.
posted by spikeleemajortomdickandharryconnickjrmints at 9:13 AM on July 17

Not the starte, the solenoid which pushes the starter pinion into the motor's flywheel. Banging around the starter should eventually hit on the solenoid case. Also check for a bad ground or a loose power cable to the starter.
posted by Gungho at 9:18 AM on July 17

Start with first things first. How old is your battery? Is there a lot of corrosion around the terminals? If it is more than 3 years old, or there is a lot of corrosion around the terminals you should replace it. This may not fix your problem, but you won't feel too bad because a battery in that state would need to be replaced soon anyway. It is entirely possible for a car with a really bad battery not to start even when jump-started. This has happened with at least two cars that I've worked on that ultimately needed a new battery and then started right up. Also, a bad battery will almost certainly read 12.5V unless it is completely falling apart, but will not be able so source the (sometimes hundreds of amps) of current that it takes to start your car.

If your battery is in good shape and you are relatively certain it is well charged, then you need to figure out where the clicking noise is coming from. If it is coming from the ignition relay, it will be a small click usually coming from a relay in the fuse box inside the engine bay. If this is the only click you hear, then the problem is in your starter. If this is the case, the starter may be dead, or the starter solenoid may be stuck. What you can do is locate the starter, and the solenoid that is attached to it, and tap (lightly to moderately hard) it with a hammer while turning the key to crank the car over. Obviously make sure the car is in neutral or park and the parking brake is on while you do this. You will need a friend to crank it while you tap the solenoid. If this starts the car, you will need to replace the solenoid (or the whole starter if they come as a unit, like a van I fixed), because one the solenoid sticks once, it's a pretty good bet it will continue to happen, stranding you in interesting places/situations.

If you're unsure where any of these items are, and you feel like you would like to do the repair once you figure out the problem/do future light repairs on your own, I recommend investing in the Haynes manual or similar for your vehicle.
posted by no1hatchling at 9:23 AM on July 17

Your voltmeter check will not determine if the battery is good. (What no1hatchling said)
Most people don't know how to jump start a battery. The last connection (negative) should be made away from the battery.
Read this and try again.
posted by weapons-grade pandemonium at 9:44 AM on July 17

To be clear, you don't hear the starter freewheel do you? It doesn't go CLICKwhiiiiiiiiiiiiiiii without starting instead of the CLACKchugchugchug of you expect, right?

Do a quick-and-dirty check. Put your voltmeter on the battery and have someone crank the car. What value did you get when the starter circuit was activated? A strong battery shouldn't drop below 9 or 10 volts while cranking. If your battery voltage plummets below that, you've got a weak battery. Also, if you crank the car and the voltage only drops a small amount, then you've got a bad connection and the starter isn't even activating. A stuck starter should draw the voltage down substantially, seing as it's encountering lots of physical resistance. If the draw is really weak, then the either the connection to the starter is poor or the starter soleniod isn't making good enough contact to run the starter motor, excluding other less likely circuit faults involving ignition switches or starter relays etc.
It's been said above that a voltmeter can't determine a bad battery just by checking its resting voltage. That's true. But you can use it like this to get a quick glimpse at what's going on when you put a load on it.

Put your jump box on, get a friend to crank the car and solidly tap the starter motor. If there's a little corrosion in the winding, the motor can bind up. Drive the car to a shop and relate this story to them. They'll install a new starter for you.
Don't worry about smacking the starter too hard. Just keep increasing the force until it frees up and starts. You'll be putting in a new starter anyway. This one just has to work one last time to get you going.
posted by Jon-o at 9:52 AM on July 17

Oh, and PS. Check your fuses.
posted by Jon-o at 9:54 AM on July 17

I have been very pleased by buying a code reader. Sometimes the car computer knows what's wrong and can save you a bunch of effort.
posted by a robot made out of meat at 10:16 AM on July 17

OK -- I've tried the hammer trick and it doesn't seem to be working. The battery voltage doesn't drop at all when I turn the key, but I hear a single faint click as no1hatchling describes.

This implies a bad connection, yes? Except that I'd doubt it's the wiring suddenly going bad in the five seconds between the halfway-successful start last night, and trying again and getting nothing.

Is it possible that when I tried to start it last night I got the solenoid turned just far enough that its brushes don't connect anymore? And if that is the case, is there a way to manually turn it back into position? Or would I have to just buy a new solenoid or starter?

(Sorry, I know these are amateurish questions; car repair is deep magic to me)
posted by ook at 10:20 AM on July 17

Check what the voltmeter reads when you engage the starter. The open circuit voltage won't tell you much of anything. It has to be under load to give you any idea if it's up to task. My money is on the battery.
posted by chairface at 10:21 AM on July 17

Mine, too.
posted by weapons-grade pandemonium at 10:32 AM on July 17

Ok, I see. Measuring from the positive terminal of the starter to the negative terminal of the battery reads about 8V (whether the key is on or not, no change.) Measuring across both terminals of the starter reads nothing at all (again whether the key is on or not.) Does that make any sense or am I measuring something wrong?
posted by ook at 10:33 AM on July 17

(I'm not sure how old the battery is; there's no corrosion at all, just a bit of rust, but I guess it could be old enough to be the source of the problem. Is there any way to be sure before I go out and replace it? If a voltmeter reading isn't good enough, what would be?)
posted by ook at 10:36 AM on July 17

Take the battery cables off the battery. Wire brush the battery posts. Put the cables back on - and make sure they're seated all the way down (use force/hammer if necessary). Try it again.
posted by notsnot at 10:39 AM on July 17

Yes, this could still be a bad connection. Happened to me constantly until I replaced the cable ends/terminals. This would prevent the jump start. Remove, clean and replace and see if symptoms change. If not, move on to other culprits liike the solenoid.
posted by RikiTikiTavi at 10:50 AM on July 17

jon-o has sage advice. The thing where you watch and listen for what happens when you turn the key is spot on.

1- Turn key to on. Does everything come on like usual?

2- Try turning on the headlights while watching the volt meter. The needle will drop a bit, but not too much. Or, watch the lights in the car and whatever the headlights are shining on. Do the headlights come on quickly or brightly? Do the lights inside the car dim slightly, but remain strong? Battery is probably pretty good. Do the headlights come on slowly and look unusually dim? Do the lights inside the car dim a lot, or start looking slightly flickery? Bad battery connections or a bad battery- there is enough capacity in the circuit to show full voltage to the meter, but not enough capacity to actually do real work.

3- Turn the key to start. Most of the stuff in the car should turn off (radio, fan, wipers). If it doesn't, you've probably got a bad ignition switch. If it does, you should hear a single, solid click from the engine area. (Well, the car *should* start, but we wouldn't be here if it worked.)

3b- No click? Electrical diagnosis time. (Somehow) connect your meter to the positive terminal of the starter solenoid. Try the key. Does it get voltage? No? Probably solenoid relay, a fuse or ignition switch. Yes? The solenoid itself is bad, or the connection is really, really corroded.

3c- Yes click, but no whirring noise? Do the dash board lights (the ones that are supposed to stay on while you crank the engine) go completely dead, or nearly? Bad battery. Do the lights pretty much stay on with no dimming? Check the starter relay, ignition switch (it might have two paths for the "start" circuit- one for solenoid, one for starter), or the connections between the battery, relay and starter. Also ground connections. Do they dim significantly, but not a lot? (Or, does the voltage not drop too much, say above 9 volts)? The connections might be bad/corroded after the battery going to the starter, or the starter itself might just have gone bad and can no longer turn the engine.

3d- Yes click + whirring noise? The solenoid has failed to engage. You can try repeatedly turning the key to start or whacking the starter in the solenoid area to free it up and this might work enough to be able to drive to a repair shop.

3e- Yes click + grinding crunching noise? The solenoid is "lazy". It is trying to engage, but goes too slowly and by the time it gets to the teeth on the flywheel, the motor is spinning too fast to engage, and just grinds on the flywheel. Whacking the starter might make it work. Another thing that has actually worked for me is to grab one of the pulleys on one of the accessories in the engine, and turn the engine a couple of degrees. This can be enough to move the flywheel to a better spot for the starter gear to engage.

4- Completely forgot about this- transmission interlock. If it's an automatic, try moving the gearshift from park to neutral and start it there. Go back and forth a couple of times. If it's a manual, throw on the parking brake and get under the dash and look at the clutch pedal. There should be a switch that the arm of the pedal either rests on when it's "up" (you are not pushing it down), or a switch that it engages when it is pushed down a certain amount. Make sure the "up" type of switch is not sticking, and that the "down" type of switch is actually getting engaged. (The switch might be somewhere in the transmission itself, I have no clue on that.)

4- Can you bump start it?



Depending on the failure, a failed jump is not indicative of much. If the battery is good, but empty, the battery will be trying to charge itself and not "give up" enough current for the starter to run. Try leaving the jumpers connected with the doner car running at high idle for 15 minutes or so (don't let it overheat, obviously). Then try.

But based on the fact that it almost started that first time, and since then as completely failed to go, I'd guess that a contact in a relay or in the solenoid got burnt up by just an unfortunate sequence of events. Or the starter somehow got turned backwards and a brush jumped it's seat. Smacking it might solve this.
posted by gjc at 11:03 AM on July 17 [2 favorites]

You can take your battery to be tested for free at places like AutoZone. And if it simply doesn't have a charge, they can also do that. This of course does require some mode of transportation or a very long walk with a very heavy bucket of acid.
posted by pwnguin at 11:07 AM on July 17

(awesome flowchart, that is really helpful.)

It's 3c, with the lights not dimming at all. I tried cleaning and reseating the battery connections, as notsnot suggested, but that didn't change anything (it looked pretty clean anyway).

At this point I'm admitting defeat and calling for a tow -- trying to replace the solenoid on my own would be a great first step towards needing to buy a whole new engine -- but thank you all for your patience and help.
posted by ook at 11:20 AM on July 17

I am convinced your solenoid/gear assembly is stuck in an intermediate position so that no juice is getting to the starter motor.

There is generally an interlock switch to prevent juice from going to the starter motor before it engages the flywheel gear because, without that, your flywheel gear would be damaged and the meshing gear on the starter motor would be stripped in short order.

The single click you hear when you turn the key now is the starter relay which supplies juice to the solenoid. Nothing else happens because the solenoid is stuck. I also think this occurred because the key slipped in your grasp, the solenoid spring began to pull the starter gear back from the flywheel, but then you reapplied the juice before it came all the way away and it wedged itself back into the flywheel, but not far enough to trip the interlock.

If this is a standard, I'd recommend putting it in gear, letting out the clutch and disengaging the emergency brake to see if I could get it to move a few inches. This would make the flywheel move, and that in turn might release the starter gear from its wedged position.
posted by jamjam at 11:55 AM on July 17

The starter solenoid does two things. It pushes the pinion gear on the starter motor in to engage the flywheel gear. But it also drives big, heavy switch contacts that provide the current to your starter motor. If the plunger is stuck, the switch doesn't make contact and no current gets to the starter motor. Or the contacts could be burned and worn out. In this case you generally replace the entire starter and solenoid.
posted by JackFlash at 1:20 PM on July 17

Are we placing bets yet?
posted by Jon-o at 3:49 PM on July 17

Well, if we are you all have until Wednesday to keep upping the ante, because that's the earliest my mechanic is going to look at it.

(jamjam totally got my hopes up, but I wasn't able to get the car to roll at all while in gear so can neither confirm nor deny that very plausible-sounding explanation...)
posted by ook at 7:36 PM on July 17

A friend had this exact problem, aside from it starting out intermittently, thus leading us to believe it was in fact an issue with the battery or the battery cables. It turned out that the starter motor itself had failed, which is why it sounded exactly like a weak battery or loose cables. You could hear the solenoid make a nice strong click, but that was it.

If I knew more about Jeeps, I could probably tell you how to make one of its relays trip so you can hear the difference. They don't sound the same at all on Hondas. The best I can describe it is that a relay clicking will usually be much quieter and will seem to have a bit of reverberation to it (the reed is slightly flexible in most relays and can be heard in a quiet environment), while the solenoid is usually pretty loud and sounds more like a solid metal-on-metal tap.
posted by wierdo at 9:15 PM on July 17

but I wasn't able to get the car to roll at all while in gear so can neither confirm nor deny that very plausible-sounding explanation

Did you have it in the lowest gear? You might have more luck with a higher gear.
posted by HiroProtagonist at 8:09 PM on July 19

And the winner is...

::drumroll::

Burned-out starter motor! Battery was fine, electrical connections were fine, solenoid was fine and not wedged around backwards or anything.

Everybody here offered solid, helpful advice; I'm marking gjc's as the most comprehensive, but thanks again to all of you.
posted by ook at 8:25 AM on July 22