No Spark help

Mattax said

Quick lesson in electric circuit.

Key off, lights off, all of the uninterupted wires connected to the battery will be at battery voltage.
Measure voltage at any of those connections or wires and they will be at battery voltage.
If we put a test light in the line, it won't light up because there is no current flowing.
View attachment 1715354986

Turn on the parking lights, and the current flows through the test lamp and eventually back to battery ground.
If the test lamp and parking lamps draw 5 amps the flow path will look like this.
View attachment 1715354994


Since there's no flow in the alternator's output circuit, it acts like an expension of the probe.
We can be pretty sure its 12.0 Volts at the bulkhead connector and the main splice. The first is relatively easy to check directly, the main splice is not.

Then the question is where is .3 Volt drop coming from?
In this example it might very well be the test lamp.
Measuring the drop directly shows that is majority of the resistance.
View attachment 1715354995

Click to expand...

Ok this is going to drive me nuts.
Ignition off and nothing extra connected ( i dont have a test light to use in between the battery to starter relay)

Battery to pos to ground showed 12.77 volts, and alternator post to ground 12.77 volts with ignition off and nothing extra connected.

Parking lights on:
Battery 12.72 volts
Alternator 12.67

I did see the the gauge drop a little.

So I pulled the engine harness connection and tested there instead of alternator. key off and lights off
Battery = 12.77
Connector = 12.72

Next I followed the connection back to the bulkhead.
I pulled the connections and verified it was clean, ran some sand paper over the males again. Reattached the bulkhead and tested at the engine harness again.
Battery = 12.77
Harness = 10.68 (WTF)

Next I pulled the fuseable link and tested there.
Battery = 12.77
Fuseable link =12.77 (at the bulkhead male connection)

Reconnected bulkhead again and probed, at the bulkhead, the wire to the alternator engine harness
Wire = 10.68

So somehow in the process of locating the issue I have made things worse :(

The thing I don't understand is no connections were removed from the engine bay when I pulled the /6 other then then engine harness connection and the transmission neutral safety switch.
What is going on? It's like the car is rejecting the awesomeness of the new motor lol. Sorry my brain is numb so I need humor.
I will have to start looking under the dash too.