[Tigers] Electrical short during start attempt

[Don Antilla]

Graham:
 Because it is difficult to troubleshoot resistive connections, I suggest
the following:
1. Set up a voltmeter (digital) with the probes on the Lead post of the
battery GROUND terminal
2. Attach the other lead on the voltmeter to the case of the starter.
3. Then have an assistant do a QUICK START with the ignition key. Note the
voltmeter for any voltage drop which would indicate a marginal/corroded
ground path. My standard is that   I don¹t want to see any more than about
0.3 volts on the digital meter.
The basic theory is that the I R drop when pulling starter current
increases as the ground path becomes corroded. It is MUCH easier and
practical to do this than to try to measure small fractions of an ohm as
you look for bad grounds.


If you DO FIND a large voltage drop, please contact me and I¹ll offer the
next steps (not all that complex.)
Regards,
 Don Antilla





On 7/22/18, 2:03 PM, "Tigers on behalf of Graham Harlowe via Tigers"
<tigers-bounces at autox.team.net on behalf of tigers at autox.team.net> wrote:

>
>
>Thank you all for the replies. (I knew I should have paid more attention
>during those EE classes!)   The starter circuit seems pretty straight
>forward:  heavy gauge positive cable from the battery to the starter
>solenoid and then to the starter/engine block.  The circuit is closed via
>the ground strap from the engine block to the chassis at the clutch slave
>cylinder and then from the chassis to the battery negative terminal via
>the
>short cable at the trunk bulkhead.
>
>The "two" ground wires that fried are actually two ends of the same wire.
>The wire enters the harness from the ballast resistor (chassis mount),
>does
>a 180 inside the harness, and exits the loom with the sending unit wire
>(block mount).  As others have said, when the heavy gauge starter circuit
>is
>open, the power seeks another ground path and the light gauge ground wire
>between chassis and block couldn't carry the load.
>
>I found the ground strap at the slave cylinder was intact with good
>connections.  I'll remove and clean up the contacts to be sure.  The
>battery
>cable at the trunk bulkhead wasn't tight.  I'll tighten that connection
>and
>hope that was the primary problem.
>
> 
>Let me know if there are any other places to look or items to check.
>
>Thanks again, 
>
>- Graham
>
>
>
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