Starter Turning Over Issue

[Mike DQ]

I've got a '72 pickup, 345 with the 727 auto. In the interest of keeping this to the point, for years the starter had turned over slowly (new battery, cables, ignition switch) but would usually start the engine and I lived with it ... until my daughter killed it completely 4-wheeling. It would not turn over. I replaced the solenoid, which got it working but it was slow again ... But now sometimes it won't turn over at all, regardless of hot or cold ... it's very unpredictable. I can see the amp gauge pegging when I turn the key to start so I know it's putting out power. But all I get is a click under the dash.

All that to say, I measured the input voltage to the relay under the dash and it's at 12V, but puts @6V out. There is another one exactly like it attached to the ashtray track, so I plugged it in and got the exact same thing. Is that what the voltage is supposed to be?

 

[FDChappie]

Slow cranking and low voltage due to heavy current draw is a symptom of a starter with a shorted winding. If your cables and battery are good I'd get a good rebuilt starter.

 

[Scoutboy74]

How about the battery? Could it possibly be weak? 12.0 volts indicates a partial discharge to me. A good, fully charged battery will display 12.6 to 12.8 volts resting surface charge. I'd look at having your battery load tested for free at a parts store before buying a starter. Is there such a thing as a good rebuilt starter these days? Not trying to be cute. That's an honest question.

 

[Mike DQ]

Thanks guys ... I'll re-check the battery and cables, it's been awhile. My wife told me to stop horsing around with old starters and get a new one. "We don't want our daughter stranded in some deliverance area." So I bought one of those gear reduction ones. Unfortunately, it's worse - won't turn over at all. The old one I replaced it with did most of the time. Who knows, maybe those are crap too.

I didn't mention that I checked the "S" voltage at the solenoid when turning the key - @ 6V. That can't be correct. I have to believe it needs at least 12 to do its thing?

Anyway, I just went out and picked up a remote starter with the logic being bypassing all the truck wiring and putting 12V (assuming the battery/cables good) right at the solenoid. If it should crank over, most likely I've got a wiring issue. Flawed logic? Probably.

 

[Scoutboy74]

Truly new parts such as alternators, starters, brake master cylinders etc. rather than re-manufactured versions are generally a better way to go when replacement is warranted. I get where your wife is coming from and she makes a valid point. Could have been a bad unit right out of the box. Sadly that's not an unheard of occurrence these days. Quality control is in the crapper far too often.
Not flawed logic at all. That's a diagnostic approach rather than blasting off with the parts cannon hoping you get lucky. A remote starter trigger is handy tool to have in your bag. You can also bench test starters with a good battery and a set of jumper cables. At the risk of beating a dead horse, I'll cap this post off by saying that every good automotive electrical diagnosis begins with a verified good, hot battree.

 

[Winchested]

Change the cables and make sure your grounds are good. Unless you know for sure that the cables are good and have low resistance why don't people do the easy things first...

 

[Mike DQ]

So, I put the remote switch on the battery and the signal at the solenoid and it kicked right over. Tells me the cables are good. I'm currently thinking my white signal wire has some sort of degradation - still holding to the belief that the 6V isn't enough to kick it into action. As far as the second relay I have under the dash, I don't see it in the wiring diagram that I found so it may have nothing to do with this.