All electrical draws kill the engine?

Year: 2001
Make: Tacoma
Model: DLX
Engine size: 2.4L
Is a lift installed: No
Aftermarket components: Aftermarket head unit, amplifier, and subwoofer.
Is there an alarm system installed: No
When did you first notice the problem?: 1/08/16
How often does it occur?: Current
What have you ALREADY replaced to try and fix it?: Visual inspection of all fuses and easily accessed top wiring near battery and alternator.
Have you checked codes?: P0335, P0340, P0500


I have a 2001 Toyota Tacoma that is acting really strange. Long story short, the bracket that holds the battery in place became loose and allowed itself to move and ground itself from the frame to the positive terminal on the battery. Looks like someone spilled solder on the terminal.

The truck intermittently can't handle electrical current draws. Hitting the brakes, turning the headlights on, going fast then letting the engine slow down into low RPMs, and using the subwoofers all kill the motor. Wipers, blinkers and hazard lights all choke the motor down when they flash. Limping it home I had to give it gas to raise the RPMs as I used the brake so it would not kill the motor. It acts as if the alternator isn't putting out enough voltage but it clearly is within spec.

-There are no burned or melted wires visible around the battery, fusebox, alternator, or initial main harness that I can see.

-All fuses checked out good including the 120amp alternator fuse.

-The battery has a good 12.7ish volts standing charge, even after overnight in the cold. Only drops to around 11.6 volts under cranking, and then the alternator keeps it stead at around 13.4-13.8 volts under idle.

-On the drive home, it popped the CEL. I scanned it and got the following OBDII codes.

• P0335 - Crankshaft Position Sensor A Circuit
• P0340 - Camshaft Position Sensor A circuit bank 1 or single sensor
• P0500 - Vehicle Speed Sensor A

I'm going to check for melted wiring around the Camshaft and Crankshaft sensors tomorrow, but to my knowledge these are just magnetic sensors for rotations, correct? These aren't electrical sensors? Would the positive terminal grounding out fry position sensors?

Would position sensors be the cause of this? It just seems so much like an issue with truck not putting out enough electrical power, but testing the alternator contradicts this. Can someone point me in the right direction?

 

It actually looks like your truck might have jumped timing

 

Keep it simple, check your ground first. Then test or try a known good battery. Good luck tho

 

Without checking everything nothing can be ruled out.

If the battery and alternator check out good .

What do you read voltage wise from the positive battery terminal to engine block.

It is possible your ECM saw part of the voltage spike .

Have you cleared the codes ??

Did they come back right away

Funny thing most often a crank or cam sensor code shuts off the fuel .

 

When you've run a high enough current out of the battery to melt the terminals like that, its behavior can become unpredictable. The VERY FIRST THREE things you should try are (1) a different battery. Borrow one from somebody if you have to. (2) NEGATIVE terminal connections to engine block and chassis, (3) POSITIVE terminal connection to power distribution panel AND alternator.

The issue you are probably up against, is that just because something reads a proper voltage while under little load, does NOT mean that all components of that circuit can handle a high current. I.e., something in that some circuit is acting like a resistor. Think of it like running your home's sewer through a 1/4 inch hose. It'll handle a trickle from that dripping faucet, but flush the toilet and bad things happen.

 

My professional opinion is that there is a good chance your alternator may have been damaged by the shorting out. I would think the output capability is low. When running you are getting sufficient VOLTAGE, but when you turn on a load and need AMPERAGE, the alternator fails, and causes the engine to die. I would have the alternator output checked first.

 

The reason why that may (probably) not be right, is that the alternator *does not* provide enough current for all possible electrical loads placed on it by the vehicle and equipment. Ever tried snow plowing with a dead battery? I have. Way you deal with it is you rev the engine up enough that while the pump is running (killing the ignition), the engine's inertia can keep it spinning long enough to finish the cycle otherwise the plow pump motor will kill the engine when it pulls a current that is greater than the alternator is able to supply. With a good battery though, that short burst of current is supplied by the battery, while the alternator charges it back up between pump cycles.

 

I disagree with you on this. In my career I have seen dozens of alternators that could provide enough current to just keep an engine running, but the moment you put an electrical load on it, the engine will die. The alternator is designed to run the entire truck with all electrical loads on it, with a 20% buffer. Now yes, you start adding extra equipment and such and things do change. He did mention an aftermarket sub amp, so that does change the maximum load. However he is saying that ANY load kills the engine. So a alternator that is only putting out say 20 amps of current because it has gone bad, could easily kill the engine. A factory alternator in good condition however is more than capable of running the entire truck at full load without ever dropping the battery voltage.

 

Like I said... if you put extra load on it, EVEN IF the alternator isn't putting out enough power to keep up with it, the BATTERY WILL, unless its a bad battery or bad connection.

The alternator can be COMPLETELY REMOVED and the vehicle will still run with a very substantial load, up to 800-900 amps that the battery can supply. Not for long, but it will run until the battery is dead.

 

In a perfect world, and in theory, yes it can. However even a good battery, if there is an internal short in the alternator, will drop voltage down low enough to shut the engine down. Most of today's vehicles have an internal protection where if the voltage drops below a certain point, it will shut the engine down to preserve the sensitive electronic equipment. I have seen it dozens of times not only at the dealership, but at my own shop.

 

@BamaToy1997 is correct. The Atl combined with a solid ground ( frame or body not a random bolt ) can very well run the full load of the truck, Will it give the Alt a full workout? Yes, but it, along with proper cooling CAN run the truck.

As far as timing goes, the 2rz is timing chain driven, so no the timing couldn not have jumped.

I second you checking the wires around the cam and crank sensors, Something is engaging a major voltage drop when you change the path of the electricity ( like turning on the lights ) check for wires touching others or frays, check fuses for burn marks even if they are still good. test wires all along them and resistance as well.

 

Hey Dusty,
I've got a similar problem here and just wanted to know what the outcome of this problem for you was. Any help is much appreciated.
Thanks

 

I've got the same problem today any of you have solve the ploblem? I apreciate your help