Battery on my 1990 jeep wagoner is being drained when not running

More details needed?

hi.
not sure if this link will help you out but have a look and see if you can find anything of use to you.
1990 Jeep Wrangler grind and grind will will not start Google Search

I've had my 1990 Wagoneer since 2007, it was an old "City Park Vehicle" so it was kept in good condition until I bought it. I ran the poor thing practically into the ground and it still runs great!

by running out any debris in your tank will get sucked into your fuel pump. REplacing the fuel pump usually means removing the tank. You can try replacing the fuel filter first its much easier and cheaper. The filter is attached to your fuel line between the tank and the engine, usually in the frame. TAkes about 15 minutes to replace.

If your battery is fully charged and all connections (both + and -) are clean and secure, put a volt meter across the battery and crank the engine. If volts drop below 9.5, replace the starter.

You need to know haw to fush what ?
Breaks ?
Coolant ?
Trani ?
Oil ?
All ?

first check thermostat. when jeep is cold take out thermostat and see if you can move any parts . It might be frozen , if its good, then your fan is not providing enough cooling through the radiator to cool engine. if the fan is working properly, then your radiator fins are clogged and u need a through flushing.

Sending unit for the fuel gauge is not grounding correctly or is bad. Temp sensor needs to be replaced.

sounds like the starter actually have some one load test it for you, might be drawing more power then it need, hence the need for a jump

Try putting it in to 4 wheel drive then put it in reverse then put it back in drive.