Car won't crank, battery fine


#1

My wife has a 2002 Thunderbird. Sometimes it won’t start when you turn the key. I don’t mean it doesn’t crank or cranks slowly, nothing happens. You can hear relays clicking but obviously no power is getting to the starter - the lights don’t dim when this happens. We’ve had the starter motor replaced. My mechanic is baffled. Sometimes this happens hourly, sometimes it will go weeks without happening – it’s been doing this for at least a year. To get it started, you just need to sit there and keep turning the key 10 to 40 times. It will eventually start. She just informed me that sometimes she shuts off the car in something other than Park, them moves to Park. Can this mess up the xmission lever position lockout to cause this? How can it just start by turning the key, only, multiple times? Remember, you can hear relays clicking when the key is turned. Ideas?


#2

“Remember, you can hear relays clicking when the key is turned.”

Do you mean when first turned to “RUN” before “START” or when turned to “START”?


#3

sounds like a bad connection to me. have the battery cables been inspected UNDER the plastic insulation, and the terminals been removed and cleaned? also the grond to block connection. the starter connection and the relay connections


#4

the lights and radio may still work with a poor connection, and just not be getting enough current to turn the starter. this has been common with our cougars and my fords in general


#5

You have a couple things, bad starter, neutral safety switch, ignition switch, battery, cable connections or even bad ground connections. I would put it in neutral next time and see if it starts. Try hitting the starter with a dead blow hammer if that does not work. Before that, check and clean all power and ground connections from the battery.


#6

The starter solenoid has two coils. These are the pull-in coil and the hold coil.

When you turn the ignition switch to operate the starter, the pull-in coil pulls the plunger of the solenoid to the contacts. Then the hold coil is supposed to hold the plunger to the contacts so the starter operates.

If the hold coil has a short, you’ll hear the plunger of the solenoid click when when it hits the contacts, but the starter won’t operate because hold coil doesn’t hold the plunger to the contacts.

Tester


#7

Because you have had the starter replaced recently. I’d have to agree with WESW and check the cables.
It takes little current to switch on and off relays, but a much bigger current to run the starter motor.
Did the mechanic do a load test on the battery, or are you assuming that it is ok…because it takes some charge. Sometimes batteries can charge enough to run lights and relays.
How old is the battery.

Too many people just check the end of the cable where it connects with the battery. THis is the most obvious place, but the other ends are just as important. I had one recently that was so rusted where it’s attached to the starter that it couldn’t carry the voltage needed to start. I pulled the cable and took it to the grinder with a wire wheel and got it nice and shiny. The car has gone a month without a problem starting.

The positive battery cable runs from the battery to the starter
Your mechanic should have noticed if it was that coroded or rusted when he replaced the starter, but maybe he overlooked it.
The negative cable runs from the battery to the engine block, and these are rarely looked at by most mechanics because they only need to be removed in certain instances. This one should be removed and cleaned…as well as where it attaches to the block.

I just reread the post and maybe @Tester; can answer this one.
The OP said that the lights don’t dim when they try to start it. Could it be that the ignition switch is bad. Normally when you move the key from "Run to Start…most things would be bypassed while you try to start…until you let the key go back to the Run Position.

Yosemite


#8

If the starter doesn’t operate the lights won’t dim because there’s no voltage being drawn from the battery.

Tester


#9

It sounds like the 2002 does not use the old Ford starter relay that was mounted on the inner fender well. I used to carry a spare with wrench and screwdriver in my glove box.


#10

@Tester; I guess I didn’t think that one thru did I. Duh!!!

Yosemite


#11

lol sarge, me too.


#12

If it was a neutral safety switch or a bad ignition switch, you would hear nothing when you turned the key.


#13

“If the starter doesn’t operate the lights won’t dim because there’s no voltage being drawn from the battery.”

Not necessarily. I’ve seen a starter fail such that battery voltage went from 12.4 to 10.2 when the key was turned to START but no hint of cranking. In fact, this is what told me it was the starter that failed.


#14

Here is a schematic. There is a starter relay, neutral switch, ignition key.


#15

sometimes the contacts go bad inside relays they’ll still click but wont make the connection if you have a meter i would check to see if power is coming out of the relay where it goes to the start. maybe try and jump the starter at the solenoid when it has the problem if your confident enough to do that just to see if it cranks. just be wary of moving parts and the fact that the engine may start if the ignitions on. also on that diagram it looks likes theres a fuse on the circuit i dont know if it runs the starter only but id check that too


#16

Thanks for all the ideas, but I don’t think anyone has hit on it. The battery ground cable is firmly attached to a shiny metal ground. Any ideas of it being the starter or solenoid can be discounted – it’s been replaced. If it were a battery problem, say, the voltage dropped from 12 to 9 volts when the key was turned to Start, the headlights would certainly dim, since they get their power from the battery when the engine isn’t running. The starter gets its ground from being bolted to the engine, but I’m sure voltage isn’t getting to the solenoid/starter motor. Someone asked if the relays clicked when the key was turned to the Start position – the answer is, Yes. From the Helm wiring diagram, the ignition key circuit is through the Transmission Range sensor (must be in Park or Neutral), then through the Starter Relay finally getting its ground through the Instrument Cluster. When the Starter Relay is activated, battery voltage is applied through the relay to the Starter Solenoid. No, running the transmission lever through its gears or leaving it in neutral doesn’t work. Additionally, when the key is turned to Start, a circuit is also connected through two other units: the Audio Unit and another circuit. The relays could be clicking in those circuits. I don’t wiggle the shift lever, I don’t bang the ignition switch, etc. Now, the key point here is, the car will start after 10 to 40 key turns, with me doing nothing but breathing. I can’t believe a bad ground is going to fix itself just by turning the key multiple times. I’m very puzzled, but I’m leaning toward the ignition switch being the problem.


#17

did you remove and clean the battery terminals and check under the cable s insulation for corrosion? some times the individual wires that make up the cable are corroded and don t don’t make good contact with one another, and thus don t allow the proper current, or amperage, to flow thru the cable. tthis is often missed, even by experienced people. and the terminals and connections could be oxidized even if there is no visible corrosion. you really have to remove the cables and clean the terminals and cable connections to tell. if it is your neg that is has the bad connection it will be hot by the time it does finally start. your positive cable could possibly be hot too if the problem lies on that side of the circuit.

I think it is either the things I mentioned above or the relay or its connections.
if it was the ignition switch, the relay would not click.

wes


#18

Why guess? Why not have your mechanic (or you) verify proper voltage and ground at the starter assembly during the no-start condition. That testing will either confirm or rule-out a faulty starter and the testing is either done or will continue upstream to the various sensors, relays, and switches until the problem is found.

All that’s needed for that is a voltmeter and wiring diagram. You already have the diagram.

A scan tool would be nice too, but probably not necessary.


#19

Tracing the voltage is a great idea. I have the voltmeter, I have the wiring diagrams, I have most of the module location drawings, now all I need is for the car to do it again at home so I can measure it. It hasn’t done it in over a week, but it’s just a matter of time. I left it at the mechanic’s for two days - it never did it and he has no ideas, except for the battery, which I guarantee it is not. I’d be interested in hearing a theory of why it tends to “fix itself” after many key turns. If I (or one of you) ever identify the problem, I’ll repost it. Thanks again, all.


#20

if the starter was just replaced like you said i would check the relay contacts and see if it has power coming out when it clicks or/and possible swap it with one thats the same and check for voltage at the starter like asemaster said cause new parts can be faulty even new ones