starter run-on

[SILVERBULLET]

i've had starters that wouldn't turn, but i've never had this
problem. i turned the key on my 74 gtv this morning. it turned
over fine and when the engine caught i released the key. but
the starter kept turning. my first thought that the spring inside
had failed (i had an old IH scout with this problem), so i quickly
turned the key back. well, the spring was fine. so when i turned
the key back the engine went off....but the starter was still
turning!! i pulled the key out and the starter was still turning!
i put it back in and turned it to the run position and the engine
caught and the starter stopped turning. i've been driving it
off and on all day with no further problems. i assume i have to
take the ignition switch apart, but i thought i'd see if anyone has
any other ideas first.

thanks

john d

[Toptick]

Sounds like a solenoid problem. I assume that when the starter was running the pinion was engaging the flywheel?

If it were the ingition switch, turning the key to off and removing it SHOULD negate the starter circuit.

If the solenoid is "sticky", the direct connection to the battery would eliminate any input from the key.

If this happens again, you ought to have a plan to disconnect the battery, or you'll burn out the starter. Replace the starter & you get a new solenoid.

[Sniady]

Always check for the simple things.

Check connections at the starter. Maybe a loose wire/connector, creating a short to ground?

[SILVERBULLET]

thanks guys
i'll check the connections and have a wrench ready in case it
happens again. these things always seem to happen if i don't
use it often enough. machines need to be used, i guess.

[tubut]

John,

My past experience with a Chevette is that, when the starter contacts driven by the solenoid start to be worn, or the battery voltage is low (weak battery), the contacts close slower (in fact, a lot slower), resulting in a longer duration of the arc that forms across the contacts when they close. This arc may be so long and strong that the contacts are welded shut. This happened to me twice on that Chevette -- and may have happened on your car, too.

A nasty side effect of this problem is that, because the starter doesn't shut off, you'll probably fry the starter motor. The only possible outcome of frying the starter motor is one immense short, followed by the wiring harness or battery cable melting or catching fire (there is no fuse other than these cables!!!) and/or the battery melting down. In one instance, I was just quick enough to pry the battery cable off with a car jack before the damage got any worse.

So, take this seriously! Remove the solenoid and check the contacts. If the contacts are pitted, replace them. And make sure you have a healthy battery.

Good luck,

Ruedi

[papajam]

In addition to the suggestions listed above, these come to mind too;

1) check that the starter mounting bolts are tight and that the special 'shouldered' bolt is in the middle hole.

2) starter relay sticking

3) and from Ripley's Believe it or Not, the cold start solenoid on the SPICA pump could be backfeeding to the starter.

To check this, the next time the starter sticks on, try disconnecting the wire that's on top of the cold start solenoid. If the starter stops, installing a relay to power the cold start solenoid should cure the problem.

[SILVERBULLET]

ruedi-
when that happened to your chevette, did it occur twice in a row?
i must have started the car 10 times after it happened and i
couldn't duplicate the problem.

jim-
where is and how do i check the starter relay?
and wouldnt the cold start wire fry if it was feeding the starter?

thanks

john d

[papajam]

There's a wiring diagram for your car located here. Although the starter relay is in the lower left in the diagram, I believe it's actual location in the car is on the rightside of the engine bay near the ignition coil.
In order to shorten testing time when the starter sticks on, using a voltmeter is out of the question. So pulling a wire or two will have to do. Having previously located the starter relay, and when/if the starter sticks, turn the ignition switch off and quickly remove the smallest of the 3 wires from the starter relay. If the starter stops, then the problem could be either the infamous seatbelt interlock system or the ignition switch. If the starter continues to run, disconnect the wire from the top of the cold start solenoid. If the starter stops, the cold start solenoid is backfeeding the starter solenoid. If the starter continues to run, disconnect either one of the two remaining large wires off the starter relay. If the starter stops, the starter relay is sticking. If the starter continues to run, the problem is in the starter itself, most likely the starter solenoid.
This is assuming that all electrical connections are clean and tight, as suggested by the Sheriff, and that the battery is up to snuff, which Ruedi brought up. Since amperage increases as voltage decreases, inadequit voltage at the starter can and will, if only momentarily, partially weld the starter solenoid contacts closed.

[Roadtrip]

Jim - I don't think pulling the CSS wire is going to prove anything. It's fed off the starter solenoid terminal and is a deadend at the CSS. I think it would be impossible for the CSS to backfeed. It could steal a lot of current especially from a weak battery, however.

[SILVERBULLET]

thanks jim. that's an awful lot to do before the starter fries! i'm
going to print this and tape it to my dash so i'm ready if/when
it happens again. the battery is good. i'll check all the connections
tomorrow and familiarize myself with the wiring at the same time.
the seatbelt interlock has been bypassed on my car, so i know
it's not that, but i'll also check to make sure the "jump" hasn't
been fiddled with.

[papajam]

I know it sounds like an awful lot to do but should probably take only 10 - 15 seconds (although it may seem like 10 - 15 minutes while doing it).

RT,
I didn't believe it either when I first read about it. I'm a nuts and bolts (and wires) diagnostician and not an engineer so I really don't understand how or why this backfeed thing happens. I believe it was the late, great Fred DiMatteo who was the first to indentify (or at least write about) this phenomonon. And Wes Ingram devised a repair that does not require a relay. Keying in the word 'starter' on the Alfa Digest search page will yield numerous references on the issue.

[SILVERBULLET]

i'm not too worried about it...i'll just review what i have to do
before i start it for the first time in the morning.
is there any other way to check the relay without the starter
turning?
thanks
john d

[tubut]

John,

No, it did not happen twice in a row. It happened intermittently, with no predicatable pattern and with two different solenoids.

It actually happened more than twice (maybe 10 times in total) and lucky enough, in most cases the contact broke free after a few seconds or by tapping on the starter. Only one event was near catastrophic.

The Chevette was my wife's car and it took a while until I believed her that something was seriously wrong (when the car nearly went up in flames in the parking lot of a Safeway).

The second time it happened was with a new solenoid -- and that's how I learned about the battery voltage.

I guess the reason why there was no predictable pattern is that on the Chevette, the starter contact is a disc around the plunger of the solenoid. The disc is free to turn about the center axis, so pitted areas on the disc may not interfere the next time the starter is being used.

The starter solenoid on the Chevette seemed to be a weak point altogether and needed to be replaced about every 18 months. When it started to fail again (for the thrid time while the car was in our posession, but I knew from the PO that he had also replaced it twice before) my wife didn't trust the car anymore and we bought her a more reliable vehicle.

Cheers,

Ruedi

[SILVERBULLET]

ruedi
if it happens again i'm going to try to diagnose the problem the
way jim said to...unless i find the time to pull the starter before
it happens again. but i'll make sure i have the right wrench and
electricians pliers handy so i can pull the battery cable quickly
without frying my a$$ or the starter.

[alfajim]

SILVERBULLET I would do the 3rd test that papajam suggested have someone start the car (air filter housing removed) and if started hangs pull the wire to the cold start solenoid. This is the most common thing I have found to cause this problem a heavy duty diode in line will cure this problem.