'84 wagon, NA automatic, 392k on the clock but as I drove around with an inop odometer for 1 1/2 years it could be well over 400k. by now I'm ready to go nuts. The starter is a sometimes thing. I've tried replacing the battery cables. I've made sure the connections are clean and tight. I had the starter reman'd by a reputable shop. I've replaced the starter switch. The master fuse is clean and dry and properly connected. Using a remote starter switch produces the same result. The integrity of the switch wires is good. The battery is fully charged and strong. When I try to start it sometimes nothing happens. No clonk, no humming, no rattling - nothing. When it does engage it is strong and turns the motor well. WTF, any ideas?

Wasn't 1984 smack dab in the rotting soy wire insulation years?

Have you tried jumper wires? Direct from the battery to you, then to the starter relay.

Can't hurt to try.

Check your neutral/safety switch.
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

You say a remote starter switch doesn't work, so this shouldn't be it, but still worth trying for an intermittent starter problem and it's easy to do. When it won't catch, run the shift lever in and out of Park a few times, then try starting again, then try starting while pushing the shift lever forward, try again while pulling it back, try again in Neutral. If it starts then it's the neutral safety switch in the shifter assembly, on the left side. You could also check with a meter at the starter to see if 12 volts is getting to the starter when the key is turned to Start (KP-III). Electrically, it acts as a cutout between the ignition switch and the starter. It's a fairly common issue with the AW trans shifter assemblies. Be careful taking the starlock washers off the plastic studs as they easily break -use a sharp awl point to lift a few of the tabs, you can flatten them later, I replace them with acorn nuts, finger tight so as not to strip the plastic. Although most people will replace the switches (available in the aftermarket), a few of us have good luck prying them open, cleaning them up, use dieletric grease for lubrication and crimping it back together. Also, if the shift lever has any back-forth slop in it then you may have one or more worn/missing doughnut bushings in the trans shift linkage rods underneath the car. When both are gone, the neutral switch may not have contact in certain positions.

If that's not it then another simple thing to try is rapping solidly on the starter monitor a good number of times with something like a long piece of 2x2. If it now catches then you know there's something wrong in the starter, like a dead spot in the windings or a sticky solenoid, rather than an external electrical problem. If it still doesn't catch, rap on it another dozen or more times. Presumably the shop replaced the solenoid? When this works I start packing a 2x2 under the seat until I can replace the starter. I usually opt for used rather than a rebuild so I don't have to leave it for two weeks at a busy starter shop, plus there aren't that many starter shops around anymore.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now