Massive power drain - help please !

[aloshan]

Hi Guys

Car: 1986.5 MA70 Supra converted to 7MGTE

I had a starting problem that I ascertained was caused by a bad battery , a bad connection to the starter and a parasitic power drain. I have both replaced my starter , my wire leading to the starter and have purchased a battery with more then enough CCA and reserve capacity. My car starts up no problem now , however my power drain still exists so I have to resort to disconnecting my battery everytime I switch off my car.

The drain is so bad that if I do not disconnect my battery after I switch the car off and leave the battery connected for 15minutes,it will drain the fully charged battery so that the car will not start.

the yellow one(30 AM FL AM2) pulls 12.73 volts with the car switched off



Ive ascertained that the current is being drawn from this fuse. If i remove this fuse when I switch my car of , the drain no longer exists

The TSRM says this about the fuse



Does this mean that I will have to check the ignitor , the ignition coil and noise filter since the EFI resister cant draw current (or can it)?

Thanks in advance for any help, have had this problem for months now and there dont seem to be any autoelecs in my area that know anything about these type of cars.

[thechuckster]

disconnect those items one at a time to see which one causing the drain and replace.

Could also be wiring between any of them and battery.

Or, during the engine swap you've got some wiring wrong and you are keeping the ECU or the igniter powered off battery rather than switched ignition. Might pay to go around to those devices that should be ignition switched and confirming that they are.

[JDM hachi]

disconect the alternator if you still have no luck with the above, if the diodes in the regulator are stuffed it will suck the power out of a battery.

matty

[aloshan]

thanks the chukster , il be checking that out

no JDM checked the alternator first , there is no drawback.

[BLK_20v]

Everything should be measuring 12volts or higher on your test for voltage.

Flick it over to amperage measurement on the multimeter and remove fuses one by one and touch either side of the fuse with each end and it'll measure the amps.

Do it until you work out which one is drawing the most amps.

[aloshan]

ended up being the main EFI relay that was stuck open...