[FIXED]95 Buick Lesabre No Crank No Start

1995 Buick Lesabre, 3.8L v6, automatic trans.

No crank no start, all I get is a click of the solenoid. DVOM shows 12.4 volts across battery terminals with engine off, and I had battery (bought new 8 months ago) load-tested at Advance Auto, it checks out fine. Connections are clean. I measured only 60 mV of voltage drop from battery+ along positive battery cable to main post on starter motor with key in crank position. Only 20mV of voltage drop from starter case to battery negative again with key in crank. Post on starter where ignition wire connects is getting battery voltage with key in crank.. I did notice that with Key off, I see battery voltage at main positive starter post where positive battery cable connects. But at same post when key put in crank position, almost all the voltage drops; down to single-digit millivolts. I think we are looking at a bad starter/solenoid unit, but I admit I have no idea what to make of that last measurement, the one where almost all the voltage drops out when measured across the starter with key in crank.

Do you guys think I am correct in leaning toward calling a bad starter?

NO! (If I am understanding you correctly anyways...)

The heavy cable on the starter should maintain battery voltage with the key in crank, if you have battery voltage there not cranking, and almost nothing in the crank position, you have a significant voltage drop on the heavy positive cable. This being a GM that likely uses side post terminals, I would inspect both the positive and negative cable ends at the battery for corrosion, which is notorious for causing this condition in these vehicles.

Wait...I misread your post and what you seem to be describing would be a connection issue between the heavy cable and the starter motor. Sorry about the confusion. :S I would check the heavy connection directly at the starter, as you should have and maintain battery voltage there in the crank position. If you have voltage on the cable, but not on the post, a connection problem is present.

I ruled out a connection/voltage drop problem on the positive side because I measured only a 60mV voltage drop on the positive side from battery + terminal to the large post on the starter with key in crank.

To be more clear, where I see all the voltage drop is with my positve DVOM lead connected to the main post where the positive battery cable connects to the starter, and with the negative lead clamped to the starter case.

Can you use battery ground for your meter and get a voltage measurement of the starter case in the crank position?

With key in crank I measured with the red lead of DVOM connected to starter case, and black DVOM lead to battery negative, and DVOM showed 20mV of voltage drop.

Now using battery ground, what voltage do you have on the heavy starter post in the crank position?

OK will do that one when I get home tonight and report back. Thanks!

Well I feel like an idiot. Finally got back out there and redid my voltage drops. Turns out I was losing 10.5 volts between the surface of the battery side post and the pos starter cable cable end where it connects to the battery. Not due to corrosion; connection was just not good. Fixed, now car starts nicely every time.

Thanks guys for all your help and guidance.

Nice work, thanks for updating us with the fix!

popoften wrote: Well I feel like an idiot. Finally got back out there and redid my voltage drops. Turns out I was losing 10.5 volts between the surface of the battery side post and the pos starter cable cable end where it connects to the battery. Not due to corrosion; connection was just not good. Fixed, now car starts nicely every time.

Thanks guys for all your help and guidance.

Glad to hear it, sir!

I got to this thread late, but this part stuck out to me:

Connections are clean. I measured only 60 mV of voltage drop from battery+ along positive battery cable to main post on starter motor with key in crank position. Only 20mV of voltage drop from starter case to battery negative again with key in crank.

Seeing these numbers, my first thought was that there's no current flow. :blink: It sounds weird, but on high current circuits like this, some voltage drop across connections is normal and expected. A few hundred mV on starter in-rush, at least, usually more.

That's the tricky part about voltage drop testing. You did the test right, and it DID indicate clean connections... between the two points that your meter was connected. Not trying to lecture you, sir, just making sense of your initial readings.