Hi all,
With an upcoming trip with the fam. I smartly decided to powerwash the under the body and engine bay. Mainly gunk around the transmission (w56) but also washed the engine bay trying not to wet the alternator and distributor.

I left the truck dry in the Texas heat for several hours. It then started right up and took it around the block before parking it in the garage.

Today, I go to start the truck and nothing. Not even a click. No lights or accessories. Take out the voltmeter and battery measures 1v. OK, so a short. Unplug ground and battery goes to 6v.

1. Removed battery
2. With the voltmeter on continuity setting, I placed one probe on negative terminal and the other probe on the 80amp positive battery cable. Short detected.
3. With the sound of the voltmeter, I started removing fuses from the driver kickpanel.
4. Short stops when BOTH engine fuse and cig fuse are removed.
5. No fuses are blown but there is a short. All fuses intact.

Besides the question of, what do you think could have shorted? Anyone have info on what the engine fuse protects? And what about cig fuse, anything besides cig lighter?

Appreciate any input. Really stumped on this one. I searched but didn't find specifics on what each fuse could short or if there is anything that could short both.

Reference to another thread but couldn't find anything on the transmission sensor wires.
https://www.yotatech.com/forums/f116/87-22re-blowing-engine-fuse-301354/

Truck details :
1985 4runner
22re engine
W56 dual case transmission
Only accessories are LED headlights, aftermarket horn and rearview camera on rearview mirror.

 

If your testing continuity between negative and positive of course your meter will sound the beep it is a complete circuit I hope the negative cable was disconnected you never check continuity on a live circuit good way to slag the meter and yourself on higher voltage

when you removed the fuses you opened the circuit.

If you had a short you would have open fuses or have melted wires till the circuit opened or a visit from the fire company if things were really bad.

 

It is a closed circuit but I would not expect it to test positive for continuity. Continuity would mean a resistance less than a few ohms which would lead to a short circuit. Is a resistance under a few ohms really expected?

I'm with you on the fuses. Not sure why they didn't blow.

Also when measuring voltage with battery installed. The voltage would drop to 0 (180mV) when both terminals connected. Without one terminal (open circuit) or would read 2v. This leads me to believe something is shorting and draining the battery.
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Something can be draining the battery but it is not a short it is a load drawing current .

Good luck !

 

Ah! Makes sense. Thank you!
Since I washed engine bay, I wonder if I screwed up the alternator. I'll recharge the battery and see if alternator is draining the battery.

 

Just measured resistance from alternator output terminal to ground and got 35ohms. Based on the thread below looks like I might have bad diode or rectifier in the alternator. Most likely due to me screwing it up.

https://www.yotatech.com/forums/f131...l#post52079473

 

A diode can be open or shorted .

With the battery disconnected check resistance between the B terminal( alternator output) and the case of the alternator you should get Over load or infinity depending on your meter display in other words no continuity at all if you do oops!

You will figure it out. Good Luck

 

battery and B terminal disconnected.
Measured b terminal from alternator and alternator case. Measured 55ohms. Looks like we have a culprit

 

I guess this gives me an excuse to upgrade to the jaguar alternator

 

Make sure to give your Truck the correct amount of anti rejection drugs to keep from purging the foreign growth

 

Well said, Wyo, well said.
Great advice.

Have fun, all!
Pat☺

 

The common Jaguar alternator upgrade is also made by Denso, so it would be more like a long lost relative.

 

I'm kind of late to the party, but I would do a parasitic load test with the alternator disconnected (since it sounds like it tests bad anyway). Basically you run your meter between the battery terminal and battery cable. Clearly leave the key off, lights off, etc and make sure the meter is setup for the high amp setup (requires moving one of the probes on the meter physically). It's normally good for around 10amp and is fused. Lower the reading the better, the computer and radio always have a load to keep memory, besides that it should be effectively zero. I don't remember figures exactly, but I think the target is under 150ma. If it's say 500ma, you can pull fuses to find which circuit is the high draw.

Technically you could do a similar test with the alternator, meter between the feed wire and the bolt on terminal to read how much of a draw it actually has.

Clearly this isn't the correct procedure if you were blowing fuses, but you aren't so it could give some good info.

I have a Lexus LS400 that would kill the battery in about a week of sitting, ended up it had something like 360ma load on the battery all the time, and the aftermarket radio was the source. Found and installed an OEM radio and now I'm sitting at around 80ma load and no more battery issues.

Anyway, good luck with the alternator update.

Also, charge that battery asap, longer it sits dead, the more damage is being done to it. Anything under around 12v is damaging it, that's partly why they are a "float" charge type of battery. Slow (low amps) charge is the best for it when dead, but even at 10amp it shouldn't be too big of a deal.