A Leak I Need Help With

[marksorrento205 80]

For some reason my car will not hold a charge for a long time. I gave it a good drive not long back (within two weeks) and went to start it today and the battery is flat. It has a 6 month old battery and is charging as it should. Is there a way of testing the car to see, once everything is switched off, if its still drawing power? If so how?

[M@tt 77]

get a multimeter, set it on amps

 

remove the negative battery terminal and put the multimeter between the battery terminal and battery terminal clamp.

 

you should see how many amps are beign drained out of the battery, then pull each fuse out of the fuseboard in turn and see what affects the multimeter reading. once you find which fuse is affecting the reading its a case of looking at the wiring diagrams and seeing what runs off that fuse.

 

Likely culprits are the central locking motors /electric windows

 

you will find the fuse that powers your stero will have a little drain on it as it uses some power to remember your station settings but it won't be too much.

 

Post up what you find

 

Matt

[marksorrento205 80]

Spot on I will try that later. Central locking is playing up as it happens. Its randomly locking and unlocking when moving and sometimes works when you go to lock it but mostly not. Sounds like a lose connection. Did not relate the two. Ill let you know. Cheers

[marksorrento205 80]

Matt, just done what you said and it was the first fuse I pulled. You will have to excuse the fact I know cock all about electrics, but I set the multimeter to amps on the 20m setting. I got a reading of -16 or -.16. I pulled the fuse that is in the permenant supply to my omex ecu and it dropped to -01 or -.01 . Plugged it back in and it shot up again. Dont quite know what I sould do here as all the wiring is as it should be as I bought a pre assembled loom and all is new. Maybe its something im gonna have to live with. I will contact omex in the new year and see what there take on it is but i would not have thought it would sap that much juice, esp when its not even on - i.e ign off. Cheers for the help.

[marksorrento205 80]

Well I spoke to omex today, and first they told me that the ecu should not have a permenant live. Then he told me, in the next sentance, that the thick red wire should be connected to the battery. So thats a permenant live then? Errr yes Reckons it could be a sticky relay which I think is dog toffee but hey ho.

[Anthony 1,000]

Well I spoke to omex today, and first they told me that the ecu should not have a permenant live. Then he told me, in the next sentance, that the thick red wire should be connected to the battery. So thats a permenant live then? Errr yes Reckons it could be a sticky relay which I think is dog toffee but hey ho.

Emerald give the same slightly confusing information in their wiring guide that caught me out first time I did a loom for someone.

 

In the case of Emerald (and I assume OMEX too) *both* of the ignition feeds need to be switched - neither should be a direct unswitched live from the battery. What I suspect the OMEX bloke meant was to have an ignition switched relay that is connected to the battery to power the ECU, so that in effect the ECU is fed directly from the battery but the supply is cut when you switch the ignition off.

[marksorrento205 80]

Yeap you are bob on. The loom has a built in relay for that purpous , and its a pre built one from omex, and you put it like that it makes sense of what he ws trying to say but did not say it

 

And the relay is working as it should.

Edited January 6, 2009 by marksorrento205