engine and drivetrain Need Advice, Starting Issue

[JLENHAM]

Thank  in advance of any guidance you can provide, sorry in advance for the lengthy post...

 

My 1973 02 is usually a regular, but not daily driver.  I have been chasing a starting issue (could be multiple issues) that seems to be recurring on a regular basis.

 

The issue:  The car will turn over at full strength for several twists of the key, then, with just a click and a puff of smoke from near the bell housing it will not turn over again.  I have replaced the battery and the starter during the last year, each replacement seemed to cure the issue, but it has now returned.

 

This weekend I installed a new positive cable from the battery to the starter, I intended to replace the ground as well, but it was out of stock.  The starter clicked and begin to turn the engine very slowly.  I connected a jumper battery and got the same results.  The negative and positive cables get pretty warm and I am being careful to not keep the key on long.  

 

So what is next?  The ground cable appears to be OK...the last time I replaced the starter I reattached the bracket at the head of the starter and the ground cable mounts at this point.  It worked fine for several weeks before this recent recurrence.  

 

Other items that I think are unrelated but I mention them here since they have come up in other posts.  Brown wire at alternator 3 prong connector is a little fried looking, probably still working though, my guess is this would be a charging issue not a starting issue.  Voltage regulator is new.  Ground wire from alternator to the block is intact.

 

Should I go ahead and get the ground cable?  What other tests can be performed?  Any of the other items mentioned need to be dealt with?

 

Again, thanks for you time and thoughts.

 

John

[Stevenc22]

i used an autozone premade ground wire and have absolutely no problems.

[AceAndrew]

John, 

Steve's on the right track, but you should be checking all your engine bay ground wires.

 

appearances can be deceiving, especially on those grounds.  You need to take a voltemeter and check resistance on each ground wire.  They can look fine, but in reality be extremely brittle and no longer functional.  I've been there and slacked off enough to set the wiring harness on fire (subsequntly having to re-wire the entire engine bay).

 

While someone is cranking over the engine put your hand close to that brown alternator wire.  If your other grounds aren't doing their job (engine to framerail, alternator to cylinder head) then the starter will try and ground through that tiny little wire (which will work to start with, but shortly thereafter will heat up and catch fire).

[JLENHAM]

Helpful advice guys, I will concentrate on the grounds.

 

AceAndrew, can you roughly help me locate the engine to frame rail ground.  Not sure I have looked at that one.

 

John

[Mike Self]

Two more things to check:

 

1.  While someone is cranking the engine, place your hand on the accelerator linkage rod (don't laugh, there's a reason).  If the engine isn't grounding properly to the body, that rod becomes the ground path and will get hot in a hurry.  If that's the case, or even if it isn't...

 

2.  Make sure your battery ground cable has a big fat strap that runs to the engine block, and a smaller (but equally important) one that grounds to the body.  Without both, you're gonna have starting problems. 

 

Presume you've already checked your alternator output, and made sure the plugs on the back of the alternator and on the voltage regulator and nice and firmly in place, and are clean.

 

cheers

mike

[Hans]

I'm guessing the puff of smoke is from the ad hoc ground connection. I'd put on new cable, clean all connection surfaces.

[JLENHAM]

Thanks again.  Here is a quick update:

 

I removed and checked the resistance in the ground strap, it was about 2.5 ohms, the same as when I connect the probes directly to each other, so my guess is that the strap is OK.  I do have a new one on order.

 

I cleaned and reconnected the ground strap, but still no go.  I am beginning to think I have received a bad starter and plan to return it.

 

Mike, the alternator connections appear OK, though the brown wire's insulation is a little melted at the plug (this looks like an old issue) a few inches back.)  The regulator is new and I have checked over the charging system.  If faulty, would these affect starting, other than not having a fully charged battery?

 

I am going to pull the starter and put a spare on this weekend.  Will report back.

[jgerock]

Check the two screws that hold the voltage regulator to the body.  That is another important ground point. 

[Buckeye]

You may want to try this procedure Before you replace that stater.

[AustrianVespaGuy]

If you have another car, try jumping it.  If you experience the same problems, then it's either your engine block grounding or just a dead-ish starter.  If the car cranks fine with a jump, then it's just that you have week supply voltage pointing to either your battery or alternator charging circuit.

 

-Carl

[JLENHAM]

Thanks again to all who provided guidance, bonus points to those beating the "check the ground" drum.  I have been working on cars for many years and am still amazed at how often the same rules apply, start with the simple things, just because it looks good does not mean it is good, just because it tests good in static does not mean it is good under load or running conditions...etc. etc. etc.  

 

The new ground cable arrived and I was able to swap it out this weekend.  Before doing so i checked it's resistance versus the old one, of course they read the same.  I was quite sure that I would be replacing the bad starter.  Of course, the two other starters that I replaced in the last 4 years should have served as a living testimony that I had been on the wrong track, but the way they smoked...

 

Anyway, ground cable changed out and with the help of a jumper battery she cranked right back to life!

 

I double checked the voltage at the battery and it was receiving about 13.5 volts, so charging function seems good.

 

So there you have it.