Complete Loss of Power

[exitwound]

This has just started recently. I'm attributing it to the weather at this point to start.

I went to my car to start it, unlocking the doors as normal (they had power) and turned the key. I didn't get a click from the starter, I didn't get dashboard lights. I got nothing. The entire car lost all power as if the battery became disconnected. No power locks. No chiming door ajar. No dashboard lights. Nothing.

I took the cables off the battery terminals and cleaned them off with sandpaper, making sure any deposits were cleaned and that the connections were solid.

Car starts fine.

A few days ago, I got in the car to go again, and the same thing happens. I have power until I attempt to start the car. As soon as I try, I lose everything as if the battery's not connected.

(Car has never had a factory alarm either.)

I am betting that I have some high resistance building in the positive cables from the battery. The weather has been slightly higher (around 40-50F) for a few weeks now but it's been rather damp and wet. I did have to clear off a LOT of corrosion from the positive terminal at one point (before this all happened) because I'm getting water under the hood onto the battery.

If when I'm turning the key, the resistance builds on the positive cable, how does one go about diagnosing or fixing this?

Anyone ever seen this?

[FLYGEEZER]

Ya gotta a bad ground somewhere. I'd start with body to engine first. This has happened to lots of 944's. Good luck, you'll find it!

[Sphinx]

you could put a cooker (tester) on the battery to test its recovery. see if its just a bad battery. could be a resistance problem too. i would start with the battery. sometimes the simplest solution is the correct one.

[exitwound]

Turned the key and got nothing. Got under the hood to see what was up.

Voltmeter on the battery read 12.20V which I think is a tad low. I put the charger on it but it refuses to charge it, saying "full charge". It's always been around 12.5V but it's a newer battery, manufactured Sept 07.

I took apart all of the pieces on both terminals and shined them up best I could. I found the negative terminal did have a LOT of corrosion between the wires. I had already cleaned up a lot of the terminal corrosion last week, which are what a lot of the flakes are atop the battery.



But what I also found was that the black wire off the negative terminal, which is the one that leads to the chassis, was extremely loose at the chassis side. The bolt was literally falling out. I tightened it back in, and cleaned everything I could with sandpaper.

Turned the key. "click click click click click click" from the starter. I still have a bad ground somewhere, or high resistance somewhere in the circuit. The negative cable from the battery to the engine block was replaced last year due to a 5V resistance drop during ignition. None of the others had. Got under the car and cleaned all three terminals on the starter with sandpaper, making sure they shined all sparkly like. Put it all back together.

Car starts.

Took it for a drive, a few miles to recycle some old engine oil and transmission fluid and power steering fluid. Car started afterwards.

I don't know which it was, but it was probably a bad connection somewhere on the starter.

Question: Should the starter have some sort of shield to protect it from the elements? Every other exposed doodad on the car does. Is it the engine panel, that large aluminum plate that is supposed to go under the engine, that covers the starter too?

[Sphinx]

I like that you replaced the vacuum lines. good idea. That click click noise is the starter solenoid engaging the gear on the solenoid to the corresponding gears on fly wheel, to begin to turn it in order to crank the motor. after it engages and goes to turn the motor (due to a low voltage situation) the power drops off and it immediately disengages again. then the process repeats causing that clicking noise. just to be safe i'd get the battery tested... its very cheap to do. also to prevent further corrosion on the terminals i suggest smearing on some petrolatum jelly (grease) ky works fine. it will stop buildup by not allowing moisture near the terminals. good job on fixing the ground. Good luck with it-

[exitwound]

So the jelly conducts electricity fine?

[mikepellegrini]

Yes, there is a sheetmetal shield for the starter (at least on my 86 951 - my 83 NA doesn't have one). The way it's situated, it seems like it's more to protect it from heat from the exhaust than anything.

[Pops944]

Clean your battery terminals/cable ends with baking soda and rinse well. After the terminals are tightened on the posts, apply the KY gel or Vaseline; this will protect the cable ends and the terminals from moisture that causes the corrosion. 12 volts on the battery before starting is okay, and will drop to about 9-9 1/2 volts while cranking. If it drops to about 6 volts you have a bad cell that could be as simple as low electrolyte or in need of a good deep charge. If the voltage drops below that you need a new battery. The next time it doesn't crank like this if the voltage at the battery isn't dropping to indicate drain for starting try using a jumper cable to jumper the ground post to the engine. If the car starts, back to ground hunting.

[Sphinx]

Originally Posted by exitwound

So the jelly conducts electricity fine?

not quite. Di-electric grease will conduct electricity better. But in this situation it just in a way insulates the terminals from moisture. There was a test done that current speeds corrosion considerable on certain metals. doing this will insure you terminals stay clean. As always clean the terminals with baking soda mixed with a little water, as the corrosion is very acidic, the basic baking soda easily breaks it down.