Engine won't turn over

[Punjab]

The other day I went to Autozone and my Explorer was really slow to start. Once it started though it ran great as usual. Again, when leaving Autozone it was even harder to start but ran great all the way back to the house. Parked it and it won't turn over at all. I have full power. Windows work fine and when I turn the key I just hear the door ding start going faster but I can't hear the starter turning at all.
I thought maybe the starter was bad so I took it into Autozone today and it tested great. Passed with flying colors. Plugged it back in and same thing, full power and no turnover at all.

My battery was replaced at the beginning of spring. A month ago I replaced my negative battery cable but it's been running fine until this started happening.

I have no idea what's wrong or where to look next.

 

[natenkiki2004]

You did the negative battery cable, now it's time to do the positive battery cable

 

[tidmarshsmiths5]

What about the starter relay? If the starter tested fine (although I'm not so sure I trust the "techies" at AutoZone - they said my battery was fine and after jumping it off several times, I bought a new one and no more problems - it was 7 years old after all), then what about this piece?

http://www.rockauto.com/catalog/raframecatalog.php?carcode=1119631&parttype=3804

 

[funfool]

check your ground from the motor to the frame, add another ground while at it, never be too grounded and fix a lot of issues.
Also remove your battery ground cable and clean both ends and the metal that it connects to.
Just sounds like a real good chance this is a ground problem.

 

[larrydd999]

Do you hear a click from the engine compartment - the 'starter relay' by the battery? I automatically change it whenever I change the starter. (And I keep a spare starter & relay in the garage since neither give much/any warning when they're about to fail.)

 

[Punjab]

Thanks for the feedback! I will check out the starter relay as it seems like it has to be a fault somewhere in that system.
I watched the kid at Autozone hook my starter up and power it. The gear popped out to engage and spun right up.
I went through the negative/ground cable again since I had recently changed it and it's as clean as a whistle, and pretty much brand new.
The other thing that tells me it's not in the cables or the battery is that I have full electrical power and when I turn the key it comes on clean and doesn't stutter like when the battery is dead.
When I turn the key to power the truck on nothing turns/spins/cranks.
So maybe the relay...

 

[natenkiki2004]

When you turn the key, it sends power to and opens the fender relay, this will click. If that doesn't click, it could be an issue in that relay or in the ignition switch.

Next; If the fender relay clicks, the starter relay is sent power, it should click. If it doesn't then it could be faulty or you could have a break in the small red power wire going to the starter.

Next; If both the fender and starter relays click, your brushes are bad in the starter but that's not the case since you tested it. However, as mentioned in another thread recently, just because the starter tests good, doesn't necessarily mean the starter relay was tested good.

Sounds like one of your relays isn't getting power. It's pretty easy to jumper/bypass them to test.

 

[larrydd999]

natenkiki2004, please don't take offense but I disagree with part of one of your statements... If the fender relay clicks, it's electro-mechanically working and the starter solenoid is 'probably' getting power, but you could still have a bad starter relay (or a broken wire to the starter solenoid). I had a broken contact inside a starter relay some years ago but the relay still clicked. I replaced the starter and found out immediately afterward that the starter assembly (solenoid and starter motor) was probably ok but the starter relay was bad. That's why now I replace the relay when (or before) I replace the starter.

 

[natenkiki2004]

No offense taken Larry, I don't think my words came out right.

My point was yours; if the fender relay clicks, that means that the fender relay is getting power and sending power to the starter. But if the starter relay doesn't click then you either have a faulty starter relay OR the fender relay internal contacts are bad.

You basically have to follow the electricity, find where it ends and suspect the component before that.

 

[Punjab]

I'm not sure what the "fender relay" is. I replaced the starter relay today and it clicks all right. There is only one click though which is what it always sounds like.
Unfortunately same problem though.
After replacing the starter relay I turned the key, heard a loud click and then basically nothing again.
It's like everything is normal until the key is fully turned and nothing happens. Which kind of makes me think that maybe my starter is bad despite the fact that I watched them test it and saw it spin. Or something between the starter and the relay but everything has looked normal upon inspection.

 

[natenkiki2004]

The fender relay is the tennis-ball sized thing on the passenger fender, just rearward of the battery.

It's a double-relay system. A thick positive battery cable goes to the supply side of the fender relay. That fender relay is triggered by the ignition switch. Once the relay is closed/actuated, it sends power to 2 wires, a thick and a thin one. The thin one goes to control the relay on the starter which allows the power from the thick one through and into the starter itself.

Both relays have to click, then cranking amps are allowed through. If only 1 relay clicks, you have to find out why the other one doesn't. If both relays click, you have to find out why you're not getting battery voltage at the starter motor via the thick cable.

 

[larrydd999]

Punjab, when the shop tested the starter, did they connect directly to the starter or did they connect to the solenoid attached to the starter? If they connected to the solenoid on the starter, you should have heard the solenoid click and seen the small gear move forward when they applied power, and when the gear got fully forward the starter motor should then (and only then) have turned.
If it were me, the next thing I would do is to connect a DMM (Digital Multimeter) to the starter relay located by the battery and find out if you're getting battery voltage on both of the large contacts and engine ground (one of them 'hot' all of the time, the other only when you turn the key to the start position). If so, then I would use the DMM to check for battery voltage between the large red wire on the starter solenoid (at the starter) and a good ground point on the engine. I suspect that you don't have voltage there, or you would hear the starter solenoid pull in.

 

[Punjab]

When they tested my starter I watched the kid hook up one small gator clip to the little metal tab which I believe is on the solenoid and then also the positive and negative cables.
In terms of multiple clicks, is there a length of time between them? Do they repeat or just happen once per turn of the ignition.
I do hear at least one definite click when I turn the ignition.
My brother in law insisted that my alternator was probably going bad and hadn't charged my battery with enough amps to power the starter, so somewhat begrudgingly, I pulled my battery and took it to Autozone (it's like 1 block from my house) to have them test it. The guy said, "it's good but could use a charge" whatever that means. So I left it there and let them charge it for an hour and a half, brought it home, plugged it in and same thing. Power on, turn ignition, hear a click, and nothing happens after that.

 

[natenkiki2004]

Electricity flows so fast, you won't hear the clicks before the starter engages. With the starter not rotating, you'll hear a single click.

What you need to do is bypass the fender relay to rule out that as a problem. You can do that with a screwdriver, just look out for sparks.

 

[larrydd999]

As I re-read the posts, it sounds like the starter relay (by the battery) has been replaced (post 9/8 at 11:12) so the issue has to be either the heavy (red) cable from the positive battery post to the starter, or one of the slightly smaller cables to/from the starter relay to energize the starter solenoid at the starter. Without using a voltmeter or replacing parts, I don't know how else the problem can be found.

 

[Punjab]

I really appreciate everyone that has helped me with this issue. I love this forum.

Anyway, I climbed under the truck again and put a voltmeter on the red cables running to the starter. Both the main positive cable and the smaller red cable that connects to the solenoid received ~12v. I had my wife turn the key to check the solenoid cable. So that means it has to be in the starter, right?

 

[DeliciousKeki]

Likely, I had to replace my starter when it gave me the single click, before that it would as you say, start really slowly and it turned on for a few more days but after that I got the single click. Later after that my relay went bad, but because my starter was good I got rapid clicking. Jumping the relay allowed it to start. Replaced relay, no more issues.

 

[Punjab]

Replaced the starter and it fired right up!

I should have gone with my gut on this one and replaced the damn thing the first time it was off but that Autozone starter test machine threw me off that trail.

I guess that test machine shouldn't be trusted very much.

Thanks again for everyone's help.

 

[larrydd999]

I wouldn't necessarily blame the machine. On two occasions (and different vehicles) I've had a starter fail and was able to get one more start out of it by tapping on the case, which got me home. It probably either moved a stuck brush just that little bit to make contact or moved the armature enough to allow the brush to bypass an open in the commutator.

 

[Bobmbx]

I wouldn't necessarily blame the machine. On two occasions (and different vehicles) I've had a starter fail and was able to get one more start out of it by tapping on the case, which got me home. It probably either moved a stuck brush just that little bit to make contact or moved the armature enough to allow the brush to bypass an open in the commutator.

True. All high torque electric motors are prone to this type of failure. It occurrs mostly when the stator and rotor end up in a perfect alignment, such that there is no "pull" placed on the rotor, its balanced. All one needs to do is move the rotor a little bit and it'll take off. Banging on the case is often sufficient to cause a fluctuation in the magnetic field and the balance is lost.

This develops over time and requires other variables to be present, like carbon dust, worn brushes, low current flow (not voltage), etc.

Bottom line: If you start to have starter problems, and it isn't the cables or relays, get a new starter. They're cheap enough. Besides, unless you've got a manual tranny, you're stuck when it happens.