Help! Engine runs for a while then just turns off

[cknowles3]

Have an 85 GTS, 22RE... Starts up fine and I can drive about a half mile and it shuts off.  It's like I turned off the key.  I have no engine, no lights, no hazards, no radio. However, the antenna rolls down, the door marker lights work and the clock in the dash is on.  Turn the key and the starter turns it over like it would start, but it just doesn't.

All fuses in engine bay are ok.  Anyone got any pointers on what to look at first? 

I hate chasing electrons!!!

Thank you in advance. 

My car is sitting at the store about a half mile from the house!  That's just far enough to be terribly inconvenient!  LOL

[twotone_ra64]

Is the main relay bad? Open it up and take a look. Could be some pesky corrosion.

[cknowles3]

Well, another twist .. after it goes it's half mile and shuts off... If I let it sit for a while (like a couple hours), I can get in it and it starts right up. 

It would be nice if stuff either worked or was broken.  Intermittently broken is both frustrating and untrustworthy!

[sirdan]

Sounds like a relay check the ones in the fuse box. When my circuit opening relay failed which is 100% not your issue here but a relay nonetheless it acted the same way. It quit working then I sat for a few minutes and it worked again.

[cknowles3]

Been poking around at this a bit... first thing I fixed was some heavy corrosion at the battery terminals.  Actually replaced the terminals and this seemed to help some.  Relays seem to be ok, but they do seem to be quite hot. 

I was able to drive it around for a few miles this time, but the dash lights started getting a little of a flicker after driving for several minutes.  Got home and put a meter on the battery terminals.  Was getting about 12.06 volts while idling.  It would run up to about 13 volts when revving.  But... when I started turning things on, I could see the voltage drop at the battery for just a moment.  For example, at idle, 12.06 volts showing, turn on the headlights the voltage dropped to 11.9v for just a sec, then recovered to 12.06v.  Oddly, still idling when I turned on the hazard lights, the voltage dropped to 10.3v for a brief momentary hit and the car almost died, but then recovered back to 12.06v.  Actually drove it to O'Reilly's to have them test the battery and alternator.  All tests passed.  I did the hazard light trick for him while their tester was still hooked up and we saw the momentary voltage drop, but it recovers and the tests still pass.  Drove home and figure I'd just make sure I don't turn stuff on when I drive for a while and maybe I can get around. 

Next day... heading to the store... (this is no lie!)  my phone is blue tooth connected to the aftermarket radio...  someone called me... radio turned itself on (due to the incoming call/bluetooth), antenna went up, car died again!!!  It's like this happens from lack of enough power to run itself.  But, this time it wouldn't start up again and had to get myself a tow back to the house.  I seem to be back to square one. 

Any idea what causes the momentary power hit that seems to be killing my car?  Alternator?  Something else?

O'Reilly's had an alternator for my car in stock, so I bought that just in case.  While I was at it (and having read enough things in the forum about bad grounds!) I also bought some new heavy gauge wire for the positive run from the alternator to the battery and for the chassis ground off the negative post.  Thinking to replace these and the alternator.  Just wanted to check with all you experts here who have vanquished various electrical gremlins in our cars to see if any of these things seem familiar to you!

Thanks for all your help so far!

[ozzie]

I'd try that alternator. If the alternator was working properly, your voltage should be up in the high 13s or low 14s. You could also have an issue with the ground between the engine and chassis, which would also make the alternator "not charge". Check voltage between the alternator output and engine block/alternator case, and compare with battery voltage.

[cknowles3]

Ok... I think I found my problem!  Bad connections!  As I was tracing wires the other day I looked at the little fusible link box hanging off the positive terminal wire.  It was all rusty under the cover where the bolts hold the wires.  Today, I decided to clean that up and, wouldn't ya know it, the two wires on one side just pulled out of the connector!  They actually came out of the crimped round spade loop connector - whatever that is called.  I cleaned up the wires and put on a new connector.  While I was at it, I put in a new chassis ground to negative battery post wire in 4 gauge wire.  She fired right up - even the starter seemed to be a bit more lively!  Voltages are up to more normal ranges - 13 to 14 volts idling and at 2000 RPM.
 Flickering lights and other nonsense seems to have gone away.  Didn't even need to change the alternator!

The two wires coming out if the top right of this little box are the ones that had come out of the crimped connector.. That seems like it's important!

Thank you all for the tips and the help!