Hi, I have a '98 V-6 Mustang. When I turn my ignition on, my dash lights up and I hear the fuel pump engage. When I turn the ignition further to start, I hear a loud click and all power is gone. I have to get out and take the positive cable off and put back on to get the power back. I've tested the starter, battery and relay's, all are ok. My thought next is the ignition switch, but I'm guessing. Any ideas? Thanks Jay

 

Could be a couple different things. how did you test the starter, battery & relays. I’m sure you did it properly, I just like to cover all the bases.

 

I pulled the starter and had it checked at AutoZone. I did a load test on the battery and it showed ok. On the relays, I just switched the two relays that are together. Next step is to check grounds and the ignition switch. This started intermittently and got progressively worse. Thanks

 

Sounds like dirty connections/grounds if your positive the alt/batt is fine.

 

You tested the components properly.

The loud click could be the starter solenoid, relay(s) in the fuse box or something else mechanical in the motor. Its hard to say without being near the car to listen to it. I’d start by making sure that the motor can physically turn over. Pull the spark plugs and try to turn the crank pulley bolt the correct direction by hand. If you can’t turn it, or it goes a little and then stops abruptly, then you may have a mechanical issue in the motor. If you don’t pull the spark plugs first, it will be very very hard to turn the motor over by hand.

If that checks out, then start poking around with a volt/multi-meter. If you know how to read a circuit diagram, you can jump the wholes for pins 30 & 87 of the starter relay and see if the starter tries to kick over. If it last longer then when you try with the ignition switch, then start looking on the ignition side of the circuit. Be careful, though, and make sure you know what your doing. If you jump the wrong pins you can easily fry the PCM or blow a fuse if your lucky.

Good luck...

 

If you simply fix it by removing and putting back the pos connector then its a connection issue. Bad connection clamp or cable can do that. It's loose somewhere. The clicking is just the bad connection failing to supply juice to the starter.

 

Yeah, true, but that could also indicate a bad computer. Pulling the battery cables also resets the computer. To test the theory a voltage drop test is your friend. Reset the car by pulling and reinstalling the battery cable. With a volt/multi-meter set to as close to 15 volts DC without going under, touch the negative meter lead to the top of the negative battery post (not the terminal), touch the positive meter lead to starter body and try to start the car. If you get a reading above 0.5 volts then you have a bad ground (excessive resistance) between the starter & negative post on the battery. Simply walk back up the circuit towards the negative battery terminal until you get a reading less then 0.5 volts and the excessive resistance is between the first point you get a good reading and the last place you got a bad reading.

You should run the same test with the power side too (but chances are its a ground side issue) by touching the negative meter lead to the positive battery post (not the terminal) and the positive meter lead to the bolt for the power cable on the starter. If you get more then 0.5 volts, then you have excessive resistance on the power side. Walk back up the power cable towards the battery till you get a reading below 0.5 volts. The excessive resistance is between the first point you got a good reading and the last point you got a bad reading.

Avoid poking wholes in wires. It just creates vectors for moisture to get in and cause corrosion. Its better to back probe connectors whenever possible. Good luck...

 

Thanks for all the responses. I changed out the baterry cable connectors. I also took the ground wires loose from the chassis and found them to be corroded. I cleaned them all and tightened them back up. Car started on first crank. Again thanks for the help.