Mikey Posted October 14, 2007 Share Posted October 14, 2007 If it's any help. I have a 300Tdi that runs flat when parked up but charges Ok when running, I have had it confirmed that the alternator is draining the battery when not running. (there is also a slight noise from the alternator when parked). Spares not available for my alternator (Magneti Marelli) so presently searching for cheap replacement. Quote Link to comment Share on other sites More sharing options...
alex park Posted October 30, 2007 Author Share Posted October 30, 2007 well i bought an new battery for £100 and it did the trick, i guess i should have listened to the posts at the beginning of this thread. Started like a dream, roared into life. the only minor niggle i have now is that when i turn the ignition on. the "check engine" light flicks on then straight off. it never did this before. theres no other problems with the engine it starts and drives fine, but just one of those niggly things. perhaps i should do a homer simpson and put a bit of black tape over where the light is ha ha. any suggestions? thanks for all the advice previously. Alex Quote Link to comment Share on other sites More sharing options...
jwriyadh Posted October 30, 2007 Share Posted October 30, 2007 The "Check Engine Lamp" is supposed to flash on during the ECU initiation sequence, standard for a 14CUX ECU. It is used as a lamp check. jw Quote Link to comment Share on other sites More sharing options...
alex park Posted November 2, 2007 Author Share Posted November 2, 2007 flat again this mroning, so i guess my being premature was, well premature. gonna check the alternator this mornign and see if i can find the culprit. Quote Link to comment Share on other sites More sharing options...
sotal Posted November 2, 2007 Share Posted November 2, 2007 Well at least you ruled out the battery Quote Link to comment Share on other sites More sharing options...
alex park Posted November 4, 2007 Author Share Posted November 4, 2007 if the alternator is discharging the battery when it is at rest, does this mean that i need a new alternator? which on of the three wires is the actual charge wire. on the back there looks to be three wires bolted to the alternaotr plus a small wire connected to blade fitting. Alex Quote Link to comment Share on other sites More sharing options...
alex park Posted November 5, 2007 Author Share Posted November 5, 2007 left the charge wire off the alternator overnight and it seems that the battery went flat anyway. so i think that will discount the alternator "back charging" can anyone tell me where the earth straps would be so i can check those please alex Quote Link to comment Share on other sites More sharing options...
sotal Posted November 5, 2007 Share Posted November 5, 2007 You should be able to see the earth straps, they're the big hefty wire going from the chassis to the battery and the starter to the chassis, the one from the battery goes straight down to the chassis, a good way to rule out a bad earth strap is to run a jump cable from the battery to the engine block. I don't think it will be the earth though. If anything is drawing current from your battery it will show up with an ammeter as suggested already. But as the others said the "1" showing on the screen should mean it's off the scale. When you disconnect and reconnect the positive terminal does the lead spark? If it does then something is draining quite a bit of power, if it doesn't then it could still be a bit of a drain. Be careful making sparks as batteries can give off explosive gases though. Also try the advice above and connect a bulb up between the battery and one of the leads Quote Link to comment Share on other sites More sharing options...
Guy H Posted November 5, 2007 Share Posted November 5, 2007 Not sure how the earth straps could effect a discharge? Anyway as your problem is a little complicated you may need a different approach. As I understand it now, the battery will flatten, without fail, if left overnight yes? If so, get a circuit diagram from Haynes or Rave and pull fuses for half the circuits on the car that are permanently live If it's flat in the morning you know it's a circuit on the other half If it's ok then you've pulled the fuse on the bad circuit Next night pull half of the fuses in the previously found bad half (IYSWIM) and repeat until one night you pull one of two fuses and Robert's you Dad's brother My first half to pull would include the ECU, alarm, stereo, interior lights Have you got a grey trailer socket fitted? HTH Quote Link to comment Share on other sites More sharing options...
alex park Posted November 5, 2007 Author Share Posted November 5, 2007 positive battery lerad does spark when i disconnect or reconnect it, so as you say it points to a big drain hence the mm showing the 1. i will go along the route of the half fuses and see what that brings. thanks for all your help guy and sotal. be lost without it. Alex Quote Link to comment Share on other sites More sharing options...
sotal Posted November 5, 2007 Share Posted November 5, 2007 No worries, if you're getting an obvious spark then something is definatley drawing power. I'd connect the ammeter up as said above so you're getting a 1 on the screen then pull the fuses one by one until it drops - that should give you an answer quicker. Let us know what fuse sorts it Quote Link to comment Share on other sites More sharing options...
Guy H Posted November 5, 2007 Share Posted November 5, 2007 My only reservation about the ammeter is that when the sidelights were switched on it read 9.4A (higher than I would have expected - would have expected more like 3A or 4A) and when switched off went back to 1. Either when the lights are off there is more current being drawn (remotely possible I suppose) or the meter involved reads 1 when the current is less than a set amount. Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted November 5, 2007 Share Posted November 5, 2007 Hmmm....I expect that the act of turning on the lights is introducing some extra resistance into the circuit at fault and therefore generating a lower reading...somehow. Treat the 9.4 as if it is still off the scale - the point is that you still have the drain, therefore you haven't yet pulled the correct fuse. Connect up the multimeter, leave everything off (drain present, so multimeter reading 1___). Pull one fuse at a time until you see the drain disappear - that will be your fault circuit. Once you have isolated it, trace wiring and components to try and pinpoint it. It is a nobflattening job, but better to find it than randomly grasp at straws hoping that you guess right. Quote Link to comment Share on other sites More sharing options...
alex park Posted November 5, 2007 Author Share Posted November 5, 2007 looks like tomorrow is going to be a fuse pulling wire tracing day. Quote Link to comment Share on other sites More sharing options...
sotal Posted November 6, 2007 Share Posted November 6, 2007 My only reservation about the ammeter is that when the sidelights were switched on it read 9.4A (higher than I would have expected - would have expected more like 3A or 4A) and when switched off went back to 1. Either when the lights are off there is more current being drawn (remotely possible I suppose) or the meter involved reads 1 when the current is less than a set amount. I thought the same as Guy - it might be that it's less than it can show with that particular multimeter, in which case you can measure using the non 10A socket but will blow the internal fuse if it's more. It depends how big the spark is, if it's quite a big spark when you reconnect then it's a big draw. Good luck and let us know how you get on. Quote Link to comment Share on other sites More sharing options...
alex park Posted November 6, 2007 Author Share Posted November 6, 2007 ok connected ammeter up inline as advised during the thread. meter reading 1. pulled all fuses from main fuse box, satalite box b and satalite box c.plus the ones in the engine bay there was no change to reading it kept a constant 1. i checked the voltage across the fuses with everything off. the following showed 12v+ all satallite b which are electric windows front/rear anti lock brakes central locking sunroof trailer lights ( i do have tralier tow hitch and electrics fitted) in main fuse box rear fog light multi function unit in satallite c anti theft alarm (fuse 1 and 5) rear air con/heater are these the ones which are supposed to be permanently live? are there some circuits that are not fused? thanks Alex Quote Link to comment Share on other sites More sharing options...
alex park Posted November 6, 2007 Author Share Posted November 6, 2007 and all engine bay fuses live with everything off Quote Link to comment Share on other sites More sharing options...
sotal Posted November 6, 2007 Share Posted November 6, 2007 The fuses are fine to be live with everything off. With all fuses pulled out do you get still get a spark when you reconnect the battery lead? Quote Link to comment Share on other sites More sharing options...
alex park Posted November 6, 2007 Author Share Posted November 6, 2007 no there is no spark at the pos terminal when all the fuses are out Quote Link to comment Share on other sites More sharing options...
sotal Posted November 6, 2007 Share Posted November 6, 2007 no there is no spark at the pos terminal when all the fuses are out put them back one by one until you get a spark Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted November 6, 2007 Share Posted November 6, 2007 If the meter is just reading a plain 1, rather than 0.01, 0.1, 1.0 etc, its most likely out of range, and not giving an actual reading at all, as has been said previously. Quote Link to comment Share on other sites More sharing options...
alex park Posted November 6, 2007 Author Share Posted November 6, 2007 ok the very first fuse i put back in was the trailer lights fuse (fuse 6 satallite 2) this made the terminal spark. i removed this and replaced the others one by one checking each one to see if it also made the terminal spark. the rest never. so the trailer lights fuse was the only one to do this. i have removed this. what is the significance of this "sparking" caused it seems by the trailer lights wiring? excuse my ignorance, like i say mechanically i dont mind fiddling around but the electrics bit scares the pants off me. also earlier GUY H asked if i had trailer lights fitted, was this because its a common fault? alex Quote Link to comment Share on other sites More sharing options...
sotal Posted November 6, 2007 Share Posted November 6, 2007 Sounds like you've found the fault, with this removed does the main terminal lead now spark when you reconnect the battery? Leave that fuse disconnected and see if it goes flat or not, but it looks like you found the culprit Quote Link to comment Share on other sites More sharing options...
alex park Posted November 6, 2007 Author Share Posted November 6, 2007 no it doesnt spark anymore with the offending fuse removed. I'll leave it removed and see if the bater flattens as you have suggested. Looks like we may be getting somewhere. many thanks, indisspensable info Quote Link to comment Share on other sites More sharing options...
sotal Posted November 6, 2007 Share Posted November 6, 2007 If it no longer sparks then it certainly looks like you've found the offending circuit. Do you use the tow bar at all? Quote Link to comment Share on other sites More sharing options...
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