1991 740 Intermittent no-start, no solenoid "click", some other strange behavior
 

Hey All,

My 1991 740 non-turbo wagon intermittently fails to start. Dash lights come on, but solenoid doesn't engage (at least I can't hear it click from the cabin). Sometimes turning the key off and back to crank starts it. When that doesn't work, a jump start seems to do the trick.

Battery is on the weak side (it cranks a bit slow). I'll be replacing it today. Could this be the issue, or is more likely something else?

Also, occasionally it will skip at idle (as if the ignition is cutting out for a revolution or two). It normally keeps running, but this occasionally stalls it. Not sure if related.

Thanks to all in advance.

See how it goes with the new battery, that may be the problem. If a jump start cures no start, then battery strength is the issue.

+1 on Lev's comment. Also make sure your battery terminals and cables are cleaned and in good shape from the battery to the starter and the battery to the chassis ground.

So... Terminals are clean, I cleaned and insured the ground from the battery to the chassis is good (even scraped away the paint on the chassis to insure good contact), installed a known good battery (fully charged, held steady @ 12.6V), brick drove fine for several trips, and then started exhibiting the same behavior.

Had the wife try and crank it while my head was under the hood. Heard a whirring sound that went away when she backed the key off. Told her to turn it to crank and keep it there. The sound returned, I put my hand on the starter, and lo! The starter was turning.

Tried the jump pack (fancy new type), failed to start. Brought out a spare battery (12.6V), jumped and still failed to start. Pulled the truck around to jump it with the motor running, started right up. Voltage at battery with truck running was 13.5V.

So, I'm guessing the solenoid on this starter is right on the edge of serviceability (either dirt or age/wear, it's probably OE @144K miles), and the extra volt provided just enough energy to get the solenoid to engage. The spare battery didn't have enough voltage, and the fancy jump pack probably didn't read a low voltage condition and provide current to the battery (I'm going to check w/the manufacturer).

I'm going to order a new starter tomorrow evening, so someone please stop me if this doesn't sound right.

Starter contact inside ignition keyhole?

Yes, the starter spins up, so it's getting power when the key is turned to start. It's just that the solenoid doesn't engage.

You need a new/rebuilt starter. The solenoid is replaceable but would cost as much as a starter...

OK, ordered a starter
 

Fortunately starters are still readily available and cheap on Ebay!

Thanks for your help guys. :)