Kevin in Atlanta

Charging at the jump post. Key out of the ignition.

@ 40 Amps the fuel pump hums.
@ 5 Amps the pump hums a bit quieter.

I guess that is a relay issue.

Mrmerlin

Kevin you should not be putting more than 12 A
into your charging system, this is how the computers and the alternator diodes and regulator can be damaged
really charging the battery at 6 amp is the best.
If the fuel pump is running then it indicated the pump is hot wired
Is it possible you have a fuel pump jumper still installed?
NOTE if the battery is low isolate it from the rest of the car then charge it at 6 amps for 5 hours

Kevin in Atlanta

I know this was implied, but with the charger off no hum. And no there is no jumper.

dr bob

Kevin --

Remove the fuel pump relay and see if the problem stays.

If it does, the problem is between the relay and the pump. If it doesn't, something is energizing the relay.


Split the problems list in half with each diagnostic step. A symptom with 16 possible causes can be diagnosed in four steps.

Kevin in Atlanta

Will do, but you have to admit that is pretty strange even for our cars. :-)

dr bob

It's the first time I remember hearing about the symptom. Doesn't mean anything more than there's a lot more forgotten than remembered, IIRC.

Kevin in Atlanta

Well, let me add a bit more. The battery has to be nearly fully drained to get this happen. At least to the point that the window motor stops mid-close.

After a while (not sure) the fuel pump stops.

I love the surprises my cars toss at me.

Shark2626

The battery doesn’t have to be nearly fully drained, it just has to be below 12V. Check the battery charge (volts) with your multimeter.

Are you really charging up a dead battery using 40 amps at the jump post? Maybe I am reading this all wrong.

Do you have a spare fully charged battery you could install to test with? If you do then put that in and start the car. Or put a running car to your dead battery with jumper cables and start the car, see how it functions. I’m not ready to freak out just yet but 40 amps at the jump post is something I’ve never heard of. Probably nothing.

Petza914

My Optima battery charger is a very good one. On a very low battery, I don't think I've ever seen it start charging above 8 A. As the battery comes up to charge, the smart charger reduces the charging amperage until somewhere between 0.8 and 0.4 Amps, then transitions to maintenance mode where it's at 0 Amps or when it automatically reengages to keep it topped up is between 0.1-0.2 Amps.

Alan

I would not charge at 40A to the jump post, I'd disconnect the battery from the car and connect to it directly. Do you know what the voltage is at 40A charge rate?

Alan

Kevin in Atlanta

While doing a timing belt tension check I pulled the fuel pump fuse while I bumped the starter via the 14 pin connector and jump post to move the engine to TDC.

When I looked at the fuse I found it was in the early stages of melting. I've pulled this CE panel and cleaned all the fuse connectors and refreshed the fuses with in the last couple of years.