Won't turn over

[Devin]

It was the battery. Apparently neither I nor the Autozone guy have an idea how to diagnose a battery.

How do I still get 12.5+ V if the battery isn't right?

 

[SHOrod]

If the internal resistance of one or more cells is high, the battery may still measure decent voltage but under load the battery will be unable to support the current draw.

-Rod

 

[Devin]

Okay, this is a bit more complicated.

 

[Devin]

Replaced positive cable: no spark.

Going to put the other cables on replacement for later. I need something sealed.

 

[Devin]

Drove to work okay today. Going to check again later to see if there is any sparking, but it may have just been curtains for that cable!

 

[ScotSHO]

3 ohms from the battery post to the solenoid post. 0.6 ohm from the solenoid terminal to the positive terminal on the starter motor.

Measured ~0 from the negative post to the ground screw next to the solenoid. From that same screw to the wire on the stud at the transmission case the testing bounced around. To the starter case it was a little bouncy but was between 0.5 and 2.5 ohms for the most part.

3 ohms is a decent amount of resistance from the battery to the incoming solenoid post. I would want to see something more like the 0.6 ohms or less. I would expect 0.1 ohms on the typical Fluke meter. Sometimes the point where you check has corrosion and artificially raises the resistance readings, but the wire is fine. Big picture - more resistance, less available voltage at the other end of the wire.

The solenoid is a simple relay with the 3rd small post being the "coil" that connects the two large posts and sends voltage to the starter.

 

[Devin]

Yeah, apparently it was an issue because the darn thing was throwing sparks!

 

[Texas Marauder]

Those terminals are meant to be temporary. I know people install them and forget it. They will always cause problems later on.

 

[Devin]

Those terminals are meant to be temporary. I know people install them and forget it. They will always cause problems later on.

Which, the clamp style?

 

[Texas Marauder]

The one that was sparking. All battery cables should have a crimped eyelet or terminal.

 

[Devin]

The one that was sparking. All battery cables should have a crimped eyelet or terminal

That would 100% be better, but I've never seen any mention of the repair terminals being temporary.

 

[Texas Marauder]

That would 100% be better, but I've never seen any mention of the repair terminals being temporary.

Now you have.

 

[SHOrod]

In any sort of humid environment they are about guaranteed to corrode and grow powder, sometimes off-white, sometimes with a green tint. Any time someone asks me about a no-start or weak start condition, these temporary terminals are one of the first things I check for. I'm glad I'm not the only one who grew up trained that these are expected to be temporary use.

-Rod

 

[SHOdded]

i once had terminals replaced by a firestone service center. lasted years, no corrosion. have to use terminal protector tho, no matter oem or aftermarket. especially on standard flooded batteries. agm is almost never an issue.