Battery being drained?

[ezell4G63]

I have a problem with my battery being drained overnight. I traced it down to the mpi relay not fully resetting. If I turn the key to the on position I hear the relay click, then when I cut the key off it doesnt reset.

Car cranks, runs, idles, revs, all perfect, just will not hold a charge.

If car is off the battery reads 12.8 volts, if I turn the key to the on position the voltage drops to about 12.6 to 12.7. And will continue to drop about .01 volts per minute.

If I pull the MPI fuse or unplug the mpi relay the volts jump back up and hold all day long.

What could cause this relay not to reset?

Car has no other problems at all. Like I sat it runs, drives, boosts, etc...

Thanks for any help or ideas!

 

[DSMSPOON]

bad ground...or the rely or fuse are bad...

 

[laserblue]

Do you mean that if you turn the key on AND THEN OFF AGAIN, the voltage drops at .01 volt/minute - because the relay stays energized?
The relay could be getting stuck [mechanically], or the relay coil could still be getting 12 volts with the key off, which would keep the relay contacts closed [but the relay is not the fault]. To tell... somehow rig up wires from the COIL pins on the relay socket [with the relay still inserted into the socket] and put a voltmeter on the wires. If the voltage stays high with the key off, then some circuitry gizmo is 'telling' the relay to stay closed. Of course...... if that voltage disappears with the key off, then the relay is faulty.

I suspect that there is an electrical problem, but I'm not familiar with that circuitry....... so I'm useless!!!!!

 

[ezell4G63]

Oh yea I meant it stay energized with the key off. If I pull the fuse under the hood it will reset and its fine until I turn the key back on wether to crank the car or just to test it, it will not reset on its own. I didnt notice this until I clutch linkage welding in which you have to pull the entire assembly out. Is there anything under there I could have missed? I looked but didnt see anything that was left unplugged! I will be going back to troubleshoot again this weekend. Thanks for the replys!

 

[N8Dogg]

Try checking the condition of your battery. Is there a build up of acid/dirt? If so then that actually causes an electrical circuit and will draw current from the battery. If there is no crud on your battery than obviously there is a load that stays on in your circuit. Maybe CD player, or if you put in a stereo system that might contribute. Maybe your battery is just low, good luck!

 

[92redman]

Like I think was stated above, use your voltmeter and go from + on the relay coil to the - on the battery. With the ignition on, you should see 12 volts and 0 with the key off. That's if it power side switched, I don't have the diagrams with me right now so I don't know how it's hooked up. If you get 12 volts all the time try going from the - side of the relay coil to the - side of the battery. This time you should get 12 volts with ignition off and 0 with ignition on. If you get 12 volts on the power side all of the time and 0 volts on the ground side all of the time, then the relay is staying on all the time. If the diagnosis implys that you are loosing power to the relay coil with key off, then it is probably the switch in the relay getting stuck.

Hope that helps and is not too hard to follow.

 

[ezell4G63]

Ok, I believe I may have found the problem. Pins 17 and 24 on the ECU are "sensor grounds". So I followed the schematics and only found one ground that was not actually grounded. It was pin 6 on the MAF. I jumped it to grouned and all problems are gone. Could someone with a meter check and see which pins on the MAF harness side of the connector, and see which if any you have a ground on.

Thanks