Jxfwsf
Well-Known Member
Grab your multimeter and set it to measure amps, usually 10A on most dmm (do not try to measure the battery voltage in this mode!)
leave the car off, even take the key out of the ignition and disconnect the negative battery terminal, close the doors.
now connect the multimeter with 1 probe connected to the negative battery post and the other to the negative car lead, if there's a drain you should see a reading
do not try to start the car.
Now if there's a reading of 1 amp or more you need to work out what it is.
Start pulling fuses out 1 at a time. Each fuse you remove check to see if the current draw has changed.
If there's no change put the fuse back in and move to the next one, rinse and repeat until the current draw drops to basically nothing (there will always be a small current draw due to the ecu, bcm etc but it shouldn't be more than a hundred milliamps).
This will tell you what circuit the current draw is on and will give you an idea where you should be looking instead of blindly pulling globes and disconnecting things overnight trying to find it.
does the oil sender control the fuel pump on the ecotechs? haven't looked at one for a while but in the buicks i've seen them fail and create a small current draw feeding the fuel pump when the car is off, not enough to run the pump but enough to cause issues
I've come across a faulty ecu that wasn't completely turning off, but that had some other giveaway signs like igniting the unburnt fuel mix in the exhaust 5-10 seconds after the ignition was turned off and the engine had stopped....
leave the car off, even take the key out of the ignition and disconnect the negative battery terminal, close the doors.
now connect the multimeter with 1 probe connected to the negative battery post and the other to the negative car lead, if there's a drain you should see a reading
do not try to start the car.
Now if there's a reading of 1 amp or more you need to work out what it is.
Start pulling fuses out 1 at a time. Each fuse you remove check to see if the current draw has changed.
If there's no change put the fuse back in and move to the next one, rinse and repeat until the current draw drops to basically nothing (there will always be a small current draw due to the ecu, bcm etc but it shouldn't be more than a hundred milliamps).
This will tell you what circuit the current draw is on and will give you an idea where you should be looking instead of blindly pulling globes and disconnecting things overnight trying to find it.
does the oil sender control the fuel pump on the ecotechs? haven't looked at one for a while but in the buicks i've seen them fail and create a small current draw feeding the fuel pump when the car is off, not enough to run the pump but enough to cause issues
I've come across a faulty ecu that wasn't completely turning off, but that had some other giveaway signs like igniting the unburnt fuel mix in the exhaust 5-10 seconds after the ignition was turned off and the engine had stopped....
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