ongoing discharge of battery
 

have 75cdti tourer 2002 plate and having an ongoing problem with a standing discharge when parked up. it is sufficient to discharge the battery over a few days. It does not have sat nav which I undersatnd can cause a problem.
If there is water in the scuttle where the emc unit is installed can this be a source of the problem?
Un fortunately had a goos garage near where I live which specialised in Rover/Mg cars but is closing down so wil have to find a decent garage in Pooleor nearby which can look after car.

Do you have a fuel burning heater? They can cause a battery drain if faulty.

On one of our cars the problem was the CD changer in the boot. It wasn't wet, but wasn't shutting down either.

A good way to help find a drain on the battery is to connect an ammeter in line with the battery and pull each fuse in turn to check when the drain stops.

Have also had water get into the driver's door cable plug connection as it wasn't fitted correctly, and once dried off and refitted the battery drain disappeared.

They can be tricky to sort - I had unplugged and checked loads of things before unplugging the doors. :getmecoat:

I'm not a diesel expert Ray but I believe that the glow plug module is near the ECM (Engine Control Module) and can cause rapid battery drain when wet.
Get in touch with club trader cb750chris who is based in Portsmouth.

Simon

Two things.

1/ Is the battery discharge large enough to show on a multi-meter ??

2/ What is your battery voltage several hours after you have switched off the engine ??

Could be a low voltage in a failing battery.---:shrug:

I assume scuttle = plenum and emc unit = engine ECU in the plenum?

If so, yes that is likely to be your battery discharge and will likely lead to ECU failure. Start by reading up on plenum drains, then you need to worry about damage due to water, to the ECU. Best to get MarinaBrian to take a look at the ECU.

if you disconnect the battery does it still goes flat?

macafee2

Had a battery drain on my car, disconnected the FBH and battery was fine! Sent the PCB to French Mike who found 4 blown resistors! Now repaired just got to refit to the car and test!
G

:wot: This must be your first test!

Don't want issues confusing and an ammeter connected across the battery, or in line with the battery with the engine running.

To the OP - Be careful not to blow the ammeter fuses. After switch off there's still 2Amps or more being drawn from the battery for the first 20 minutes or so. Disturbing the battery connection (disconnecting a lead) or any door bonnet or boot will restart the process. If you are going to use an ammeter to measure the drain then make sure it's capable of a minimum 3 amps. Or Use a shunt cable for the first 20 minutes of it standing - then remove the shunt to let the current flow through the meter. (if you don't understand the last sentence then find an auto-electrician to do the testing.)

Avulon, honest question, what is causing the 2 or more amp draw? The Fan?

macafee2

The 75 has what might be considered an easy way to check the discharge when the car's electronics should be all asleep...

In the engine fuse panel can be found a short section of bus-bar, which links the battery, to the entire rest of the fuse panel - with the exception of the alternator and starter motor main supply cables. Removing that bit of bus-bar, isolates all of the car except as mentioned above. The bus-bar link is fixed in place with two torque type bolts/screws and is very easy to remove.

An amp meter can be connected in parallel with that link, from the battery +ve, to the rest of the bus-bar system in the fuse panel, will allow you to easily measure the current drawn by the car, once the systems are supposed to asleep.

You connect the meter with the link in place, allow the car to go to sleep, then disconnect the link to measure the discharge. The meter connections should be good ones, because any disturbance of the power, will wake the car back up.

It sounds complicated, but it is not - it makes sure the car has properly fallen asleep to get a valid value.

Actual discharge on mine was below 20mA with car locked, pulsing to around 30mA with car fully asleep. Discharge will vary greatly, depending the spec. of the car. Mine has everything installed, except I swapped my Hi-Line ICE for a Radioguy unit.

I wrote a how to for this - https://the75andztclub.co.uk/forum/s...tery+discharge