EFI fuse draining battery

I have a 2016 ORP 99k miles. Recently I have had an issue with battery draw. My battery of 6 months randomly began dying. Very weak crank then start. I replaced battery and next morning it this battery was dead. I had this second battery load tested , alternator was charging well and battery was good. Meanwhile I had original battery on trickle charger. Now I have two batteries. I re installed original battery after full charge . After two days the crank became very weak again. So now I know I have a parasitic draw. I test for draw with multimeter . I get 1.88 amp, I began pulling fuses , I came to 25amp fuse EFI my meter came down to 0.12. FOUND my draw. My question is, what’s connected to EFI to cause a draw of power over night? I see 3rd gen’s have a EFI relay but my 5th gen I do not see a relay, only my 25amp fuse. I should note I have zero issues with vehicle when battery is fully charged . No idling issue, no fuel intake issue. Just the power draw. When truck is off I can hear a noise near fuse block and when I pull the EFI fuse it’s dead silent. So this has got to be my power issue. Thank you for any insight to what’s connected to this system .

 

Any wiring mods? Sometimes people add mod wiring like Raptor lights to the EFI circuit.

 

I have after market ditch lights , lights in the roof rack , wench, and light bar in Bully bar. I don’t do the install. But after the install there was no issues , this just started . Install of items was a year ago. I’ll add that I did disconnect all wiring from battery for the aftermarket items to rule them out . They should not be receiving power

 

^Are there any fuse taps (aka add-a-circuit) in the two fuse boxes?

 

You need to let all the modules calm down before doing a draw test. Leave it overnight, then do the test without turning anything on.

 

When you're testing for current, are you disconnecting the negative battery cable and inserting the meter between it and the negative terminal on the battery? 1.88A is a big draw. I would think it would take out the fuse in the meter.

No alarm, remote start, etc.?

 

Yes, removed negative terminal , insert milli meter into terminal and then Touch top of battery post. It read 2.20 then shortly fell to 1.88 and remained steady at 1.88 untill I removed the EFI fuse

 

I don’t see any fuse taps no, nothing out of the ordinary, no extra wiring . Everything seems kosher.

 

No remote start or alarm, truck is all stock , stock radio . Besides after market lights , and lift and wheels that’s it

 

So a 24hr period? Is half day enough?

 

A few hours.

 

If you disconnect negative, wait for awhile, then put your meter into the circuit you have just "connected" the battery so things will wake up and draw power. Pretty sure that approach will give false reading. The ring style, clamp around the wire is non intrusive but also less accurate and more difficult to measure mA loads.

Any chance your vehicle has a LoJack? I have been wondering if my 2016, with 2016 LoJack, is causing parasitic draw.

 

You speaking about an amp clamp? I don’t own one. So I’m doing it the old fashioned way with connecting to negative terminal and battery post. Seems to be the most common without an amp clamp. I I have the truck sitting tonight , no power connected . Gonna check in the morning with full charged battery again. See if I get anything different. I’ve heard that it sounds like the ignition isn’t shutting off which is causing the draw . Definitely a click sound of a relay when I remove that 25a EFI fuse

 

Without reading back through everything, my son bought a used Corolla a few years ago. After a year or so of ownership, he started having weird problems. Battery going dead after sitting two days, starter remaining energized for a couple seconds after the car was started, etc. While troubleshooting for a parasitic drain, my meter pegged twice and the fuse blew inside it. The car did have an aftermarket remote start, and I think it was intermittently engaging. I located the two 30A fuses for that in the steering column and removed them. Problem gone. That was three years ago. But it did take out the starter and battery during all this, and I think it worked the alternator pretty hard. No aftermarket electrics for me.

 

My 2017 SR5 has a driver power seat. The power is always on, because I can adjust seat without ignition on. The passenger seat is mechanical-not power. Under the passenger seat their is a translucent electric connector that is not connected. My guess (as yet untested) that the standard wiring harness comes ready for a power passenger seat, so it also could be always hot. Can it be shorting against something you store there?
A seat cover could be triggering a drivers seat switch or perhaps a seat adjustment switch is damaged?

I have been wishing to check the in cabin fuses for power seats to see if their is a fuse for the passenger side. But a sore back is preventing me from the required contortions. Does anybody know?
I have a GMRS mobile radio that I plan to put under the seat-a power connection already wired would be great!

 

This was this morning after letting everything sit over night without power .

 

That's an insane draw. Start pulling fuses until you find the one that lowers this to under 50ma. Of course put each fuse back in before pulling the next.

 

^^^What Rocko9999 said.

Be mindful that interior lights can mess with you (anything that turns on when you open a door), so turn them off or manually close those switches.

 

Just thought about this when I mentioned doors. With my 2019, I've experienced a scenario where the tailgate wasn't fully latched. It wasn't enough to indicate door open or turn on an interior light. But it did make an occasional chirp when going over bumps. Just thought I'd mention this. Not likely your culprit.

 

So when you remove the EFI fuse, your draw goes away. You had 4 aftermarket electrical items installed a year ago and had no problems. Of course, things can fail over the course of a year, as I'm sure you're aware. So one of these could have a failure, or perhaps a poorly-routed wire finally chafed through the insulation. But you've electrically disconnected all that. One thing I would do if it were me would be to make absolutely certain those items have no voltage at the items themselves.

Another thing I would do if you can - disconnect the EFI connector at the EFI module, then re-insert the fuse and measure. It would at least help to eliminate or confirm a fault within the EFI module itself.

Also, just curious - did you measure the EFI fuse for resistance? Sometimes a fuse 'partially' fails. If you measure resistance, that's a problem.

 

Here we go!!! Daddykool you sparked my curiosity about my aftermarket lights be absolute certain they are disconnected . I had the power wires disconnected but not the grounds. I pulled the grounds from the battery and bang . This is a good spec ?

 

I have run into issues where key fobs are stored. If the remote is too close to the truck, it will keep waking up. A bedroom over the garage, or a kitchen off the garage. Or if parked too close to the house. Disregard if you have a turn key.

When using the meter, try wrapping a piece of wire around the battery terminal tightly, and wrap the other end around the lead. Be sure wait at least 10 minutes for the truck to go to sleep. Every time you move the leads off, the different modules will wake up.

 

Woo hoo! Good catch! 131mA might still be a little high (I think the target is around 50mA), but certainly much better. Might settle down after a few hours of quiet.

Odd that disconnecting the grounds was required - unless one of the grounds is actually power, due to a mis-connected wire...

 

I'm glad someone pointed this out.

That's in range but slightly high for something as simple as a 4Runner. Ideally you should be around 75-100mA but anything under 200mA shouldn't be killing a battery.