spark and no spark
Very interesting results.
With the meter clamped to the large bolt on the starter, the same one that holds the + cable from battery, with the grounded going to the motor. 12.2 volt initially and 8.37 volts when cranking.
So from there I went from the motor being the ground to a place on the frame I cleaned off as ground. The meter now is 8.57volts initially and 5.7volts when cranking. This is with the meter still being clamped to large + starter bolt.
Please be EXTREMELY specific when posting where you connected and what you did.
The reading at the starter stud is obviously low. So now we need to figure out
"Is it"
in the ground circuit?
in the hot circuit?
Or a bit of both.
YOU KNOW the cranking voltage to the engine / starter is LOW. WAY too low. That voltage should not be below 10.5, 10.0 at worst
So now do this
Determine ground circuit or hot circuit
Easy........
Clamp one meter lead to starter large stud
use your extension cable and run back and have a partner "stab" the remaining meter probe right into the POS battery post
Crank the engine and read. You want "lower the better" and more than .2--.3V (3/10 of one volt) is too much.
If that is OK, check the ground.
Same thing.......
Clip one meter lead to the engine. Run your extension back and stab into the battery NEG post. crank and read. Same as above. More than .2--.3V is too much, the lower the better.
How to narrow it down?
Let's say the hot side showed OK, but the ground showed a lot of drop. Leave one probe clipped to the engine block as before. Move the remaining probe
to NEG cable battery clamp. Crank, read, post back.
Move probe to stab into the trunk sheet metal near battery cable connection. Crank, read, post back.
Now, move up front.
Leave one probe clipped to engine. "Is it" the ground cable / K member?
Stab remaining probe into body sheet metal, the firewall. Crank and read
Move remaining probe "stab" into K member near where ground cable is bolted, crank and read, post back here.
I wish some us could get together. I could teach some of you more about voltage drop and troubleshooting in 1/2 hour than I can typing pages on here.