New starter for 86 Volvo 240 installed but still have problems.

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Apr 27, 2010
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Suburban Washington DC
When I turn the key I get a faint bump from the solenoid, but nothing more. If I touch a wire connected from battery + to the solenoid, it starts right up. Hurrah! I bought it as a no run and the engine sounds strong. Thinking it might be an ignition switch problem assuming the wiring from the switch to the solenoid is ok?

I could check the resistance in ohms from the switch to the solenoid but that would be meaningless unless it was obviously open. I want to try a South Main Auto test by connecting a test light to the disconnected solenoid wire and ground and turning the key to start. The brightness of the bulb would indicate how good the circuit actually is. Just not sure what size or type of bulb to use. Have this tail light bulb and socket that draws about 2 amps. That enough?

IMG_9144.JPG
 
That's only an approximate method, no good. Use a volt meter, measure it while attempting to start the engine with the circuit under load..Work your way back towards the ignition switch.
 
Those Volvos had problems with disintegrating wiring insulation. Look for a break from the starter and jump the suspicious place if you find one. Pictures are helpful with the Dx.
 
Also, the battery light is on. Checked the voltage while running and it's 12.1v so the alternator isn't charging.
That's only an approximate method, no good. Use a volt meter, measure it while attempting to start the engine with the circuit under load..Work your way back towards the ignition switch.
Measure which circuit? The solenoid or starter?
 
Your tail light bulb will be a fine draw for testing your ignition switch.

Your alternator issue could be "car sitting around" issues like glazed or stuck brushes.

Depending how it's wired, one or some of your relays could have given up the ghost. A good example is the "fuel injection relay", those give up all the time. In 1991 at least they had low-lead solder that didn't stick very well. You can pry apart your relays, look at the solder connections under a 5x loupe, and if you see cracks, reflow them with an iron.

Also, finally, if the alternator truly was bad the previous owner could have desperately tried starting it with a low battery. Counter-intuitively, this flows more amps albeit at a very low voltage and can fry marginal starters and wiring.
 
When you say battery + to solenoid, are you running a light gauge wire directly from battery post to solenoid signal terminal? That would lead you to ignition or safety switch issues. If you meter between battery + post and batt +connection on starter while cranking you are looking for an almost lack of voltage. If you spike voltage, resistance is present in main cable to starter. It's taking path of least resistance. Same can be done on neg side and switch.
 
Those Volvos had problems with disintegrating wiring insulation. Look for a break from the starter and jump the suspicious place if you find one. Pictures are helpful with the Dx.
Depends on the year.
The wiring harness issue affected early to mid 80s models. After that they were fairly well made.
 
Also, the battery light is on. Checked the voltage while running and it's 12.1v so the alternator isn't charging.

Measure which circuit? The solenoid or starter?
If you don't know after the tests you done so far, you should take the vehicle to a shop for repair.
 
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One would think that light bulb shown would be sufficient, but maybe not. I've melted insulation on test leads jumping a starter solenoid before!
What's the fuse size on the circuit for the starter solenoid?
 
Found multiple issues.

1). Neutral starter switch had too much resistance. Took it apart, cleaned the contacts and that's fine.

2). I accidentally left the battery cable off the starter. I had tucked it down under the frame and didn't think about it since the alternator cable was connected and it looks about the same. Put it back on and that's fine.

It started up fine now, but 20 seconds later the solenoid engages all by itself and makes a horrible noise as it contacts the ring gear. Probably why the car was donated in the first place. I found one of the wiring harnesses that has the solenoid wires has the insulation deteriorated and the wires are all shorting together.
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Ordered some new pigtails and terminals and will bypass the harness. With that connector disconnected, it starts and runs fine by hotwiring the starter solenoid so at least I can move it around.
 
That's a pretty good example of why a continuity test can let you down sometimes. Sure, volts are getting from a to b, but not effectively. That's where a load test is a tie breaker. Those wires are kinda like a pinched nerve in your spine. A signal is going to your brain but it is a jumbled up,haywire mess.
 
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