'89 740 Auto 110k miles

I did a search, and it seems most of the intermittent starter issues involve the starter NOT engaging at times when the key is turned to "Start."

My starter ALWAYS engages instantly , then often cranks (at full speed) for only a half-second to maybe 2 seconds, and then cuts out like the key has been turned off. No slower rotation like a weak battery or connection-just NOTHING.

It did not do this with my 24 yr old OEM starter EVER, but the original started cranking a tad slower, so because I was leaving the car 1000mi away from home where my wife often uses it at our condo, I replaced it w/ a brand new one (NOT rebuilt) as a precaution.

The new one worked fine for a month until I got it to the condo, then it started this cut-out thing.

I managed to get a voltmeter on the solenoid activation terminal when it when the starter was not spinning one day when I was still w/tehe car at the condo, and it showed 12+ volts, as did the main solenoid stud (the one connected to the red battery wire), so I figured the solenoid was internally intermittent.

I just had a NEW replacement starter sent out under warranty, and my step-son installed it today, and for several starts it worked perfectly. Then, it reportedly started doing the SAME thing. Needless to say my wife is not happy.

It's VERY unlikely the second starter is bad as well, so I was wondering if anyone else has had this problem?

To re-cap, the starter is spinning normally (but not long enough to start the car), when it suddenly just quits. If you re-engage it w/ the ignition switch it ALWAY starts spinning instantly, and may or may not spin long enough to start the car. It may take 3 tries before it cranks long enough to start the engine.

When the starter is spinning, the engine turns over at normal cranking speed, as it should with the NEW battery it has installed.

I cannot believe the starter GROUND is intermittent, since it's well grounded through the 2 mounting bolts to the bell housing. And the last time, I DID have 12+ volts at the starter when the starter wasn't spinning, so other than a bad ground, I don't see what could be wrong unless I DO have another bad brand-new starter, which seems VERY, VERY unlikely to me.

I admit I cannot now check voltages at the terminals (as I once did, since I am not "on-scene"), so there is always the possibility than now I have a bad ignition switch, park/neutral safety switch, or bad wire somewhere).

The ONLY wild card is that the car was once equipped w/ a Clifford anti-theft alarm that used to drain the battery if left for a long time, which I disabled by cutting some wires and a motion detector switch. They tied in everywhere, but that never seemed to be a problem before, and if it were the problem now, I would think it wouldn't be intermittent, but who knows?

I told her to try starting it in neutral next time (the start inhibit switch should allow starting in park or neutral, I think) should, and maybe that will tell me the story, but until then...

I'm stumped!

Anyone??

Thanks,
Bob