Hello Fellow F150 owners,

I have read all the posts here, and have not seen a similar problem, so here goes. I have had my 97 F150 4X4 for six years and I have had this starting problem for most of them. That is, many times when I turn the key to start it, everything goes off ( as in gauges, all lights, etc) but the starter does not spin. I then relase the key, wait a sec and try again and the engine turns and starts. There seems to be no rhyme or reason as to when this will happen. In the past, there has eventually come a time when it will not spin at all. In those case I have repalced the starter ( twice i think) and the battery once (two years ago). It is doing it again, and I would like to get to the bottom of it this time. Could it be the starter relay? I think I replaced that as well four years ago. I beleive it is mounted on the firewall next to the battery, in front of the pasenger side? Anyone seen this happen or any idea what might cause it? BTW, the truck has 74,000 miles on it. Thanks for any assistance and or ideas!

 

Your symptom is NOT of a starter or battery fault, but of a power feed problem.

You will likely find an intermittent battery cable or connection to be the problem.

When the starter motor load is thrown onto the circuit, you're loosing all power (you said the lights go out). This is almost ALWAYS due to a cable or connection in the battery cables.

Simple to isolate provided you have a voltmeter, a helper, and can catch the fault in the act.

Just connect the meter leads across what should be a direct connection, ie, battery positive terminal to the maxi-fuse/starter relay, the starter relay to the starter motor, or the negative post to the engine block, and have your assistant turn the key to START.

A GOOD connction/cable will only show a few tenths of a volt of drop across a solid connection when the starter motor attempts to engage. A BAD connection will show several (up to most of the battery voltage) volts across a high resistance cable/connection.

Perform the same test across the battery posts to make certain the battery has not failed.

Steve

 

Cleaning & tightening the battery cable terminals (all of them) is a good idea, but I'd check the ignition switch alignment & the steering column tilt for slop.

Put a 12V test light from the LB/R wire at the starter relay to ground & put it where you can see it while cranking (under a wiper?) for a week or so. If it comes on when the starter DOESN'T spin, move its positive lead to the small trigger wire on the starter & keep watching. If it DOESN'T come on when the starter doesn't spin, it's definitely in the ig.sw.

 

His power is getting lost when the starter motor tries to engage. This is almost always due to a high-resistance conductor/connection in a high current circuit.

Only the starter motor makes this kind of demand (150 Amps or so) on a vehicle's electrical system.

Steve

 

Odds are, if it's a 97, the starter cable has corroded down on the starter end. Flexing the wire when you change the starter helps reestablish the connection... for a while, but not forever.

Again, as mentioned, the thing to do is catch it when it won't start. Check the trigger wire on the solenoid on teh firewall, check for power into and out of the solenoid, check for power at the starter. You can do it all with a 12V test light in about a minute once the hood is open, but a visual inspection of the starter end of the battery cable will likely show it to be all black, if not green and fuzzy.

-Joe

 

I get the impression he just means that everything goes off like normal, due to the ig.sw. being in the START position, and since the engine isn't spinning, he notices that the dash goes off.

If it was arcing at the battery terminals, it's not likely that...If the terminal was really burning, he'd have to move it to get power back. It wouldn't just come back on its own every time.

 

I had this happen to my '99 F 150 when i installed an Alpine amp. I didnt tighten the positive battery terminal enough and when i turned the key everything would shut off. Try tighting your connections and checking for corrosion/rust/etc.