Why would my engine drain my battery when off?

Andy · 08 January 2018, 22:58

Yam 200HPDI, 2003.

Recently, had a dead battery after standing for a while. I replaced the battery, charged and connected and it drained again over a week.

On testing I see the engine is pulling 0.35amps from the battery even when the ignition is off.

When connecting the battery I hear the main solenoid click in the engine. As I say the engine ignition is off ... what's pulling this current.

It never used to do this but has started to.

Something must be grounding, maybe in the helm ..... any ideas?

paintman · 09 January 2018, 11:07

Usual way to detect a parasitic battery drain is to connect a multimeter between the battery live terminal (usually +ve, but this is assuming you are -ve earth) and the live lead.
Then start pulling fuses - or disconnecting stuff - one thing at a time. When the voltage drops you've found or at least narrowed down the problem.

Xk59D · 09 January 2018, 12:11

Speak to Davie on the forum, he may know what it is off the boat.

spartacus · 09 January 2018, 13:04

Take it there's a battery isolator fitted? You can check with multimeter at the engine for reading.

If that's working - then look at what else is connects direct to the battery that by-passes isolator.

Gynner · 09 January 2018, 14:58

Thought that was what main battery switches were for.

Xk59D · 09 January 2018, 15:17

Main battery switches are not there to hide faults in other electronics. A good idea yes but a fault is a fault.

Gynner · 09 January 2018, 15:23

Might not be fault. Could be a the tank gauge, an electronic bilge pump, any number of instruments.
That said, I'd def also try to figure out what.

Xk59D · 09 January 2018, 15:32

It never used to do it....it's a fault somewhere then?

jeffstevens763@g · 09 January 2018, 15:53

faulty ignition switch if the solenoid is pulling in without turning on?

Bobg · 09 January 2018, 16:19

If you remove the feed from the ignition switch to the solenoid, as close as possible to the ignition switch, does the solenoid click out? This may involve cutting the wire as close as is reasonably possible to the ignition switch. If it does affect the solenoid, then it is the switch

Check for chafed wires in the wiring loom, especially where it goes around tight corners or through bulkheads. Does 'massaging' the wiring loom along its length have any effect on the solenoid. If so it is chafed wires within the loom.

If that does not get you anywhere, then leave the multimeter connected from the battery terminal, and disconnect everything, one wire/fuse at a time, then replacing it if there is no change to the current drawn. You will find the wire which is causing the problem when the current drawn drops to zero.

Do not attempt to start the engine with the multimeter connected. It will either blow the internal fuse in the multimeter, or destroy the multimeter. You just need patience and a bit of nouse.

Re:-It never used to do it...
The chap told the policeman when he crashed his car due to brake failure. 'They worked yesterday!'

Andy · 09 January 2018, 17:09

Thanks for the replies.

Davie · 09 January 2018, 19:10

6.8 meter with a 703 side mount??? It must have a join somewhere between control and engine as cable is only 5m long. Disconnect the harness at the plug to control box and this will rule out the power loss on that cable. Are the battery cables going through a trunk and in the bilge water? Bad insulation and tracking back through the bilge water causes this exact problem. Remove the battery cables and substitute the cables with jump leads to prove this one.

Andy · 14 January 2018, 16:29

Cables are all good. helm good. Its something in the engine thats causing the power drain and the main solenoid to click when battery connected, ignition off. Ran out of time to look further today.

Davie · 14 January 2018, 16:38

Did you try disconnecting the main harness plug? This would rule out the ignition switch and getting 12volts to the yellow wire somewhere in that harness.

Andy · 14 January 2018, 23:49

No. But I removed everything but the bullet plugs off the helm and gauge end. I will unplug engine side later in the week to rule out the cable. Thanks for the support.

Andy · 21 January 2018, 13:12

Quote:

Originally Posted by Davie

Did you try disconnecting the main harness plug? This would rule out the ignition switch and getting 12volts to the yellow wire somewhere in that harness.

I have disconnected all helm wires at the engine and the problem persists.
The main relay has 12v across it making it click when the battery is connected.

I am going to dismantle so that I can check the wiring into the ECU & connectors next unless anybody has other ideas. I am getting close to the point of passing to an engineer.

Trouble is the engine wont start now either since we saw this problem, so I can't get it to Kevin Mole on the Isle of Wight. Ideally need a Yam specialist near Portsmouth if anyone knows of one.