tested alternator i think????

ok as gav said i put the tester to dcv 20 and with it off the battery was reading 12.35 and with it on it was reading 12.03 this means nothing to me i hope someone can tell me? gav!!

with what off? do you mean Engine running? It should be reading 14v or so with the engine running and alternator working. however, It may need a blip of the throttle to activate the alternator/charge. my 300 tdi defender will start and idle for a bit before i notice the voltmeter registering its charging. A blip of the gas starts it going though if im just sat around.

G

yeah that was with it running and off so this means nothing then?
doing this as im having to change battery every day dont get long we one

Sounds like the alternators not doing its job. As Griffdowg says there should be just over 14v with the engine running and the alternator working.

right went on again and kept revs up at various setting like 2000 1400 etc and still reads around 12.00 which is less than it off so is that conclusive?

I'd say it shows theres nothinig coming from the alternator to the battery. Worth checking that the alternator is turning and also the cables from it. These can corrode over time so worth setting your tester to ohms and measuring the resistance of the cable from the alternator to the battey and also the ground cable. You want as close to zero as possible when measuring these. If they are ok then it looks like the alternator isn't putting out anything. This could be the windings burned out or the rectifier has failed.

so i have the r/r running when doing this? theres nothing on my tester saying ohms?
i have dcv/acv/ dca one at bottom is like a horse shoe shape with feet is this it? and setting are 2000k 200k 20k 2000 and 200 and the alternator has 2 cables to the rear so do i stick both testing pins on together?? there is no corrosion looks good connections and cables as its not long back on after doing head gasket so one cable is power/battery and other is ground yes? and i want 0 on them both?
sorry not done this before

goonarmy said:

Ohm - Wikipedia, the free encyclopedia

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:doh::doh:

right so thats ohm lol sorry for not being good with this stuff i worked in building industry for last 18 years i know very little bout cars or electrics im trying my best to learn

wrxfifer said:

right so thats ohm lol sorry for not being good with this stuff i worked in building industry for last 18 years i know very little bout cars or electrics im trying my best to learn

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Int we all mate?Good luck with it, your having bit of a rough ride.

so set it to ohm and what setting within this? then car running yes? then where do i put the testing terminals? obviously to the cables from rear of alternator but both on same bit or one etc?

wrxfifer said:

so set it to ohm and what setting within this? then car running yes? then where do i put the testing terminals? obviously to the cables from rear of alternator but both on same bit or one etc?

Click to expand...

Definately NOT WITH THE ENGINE RUNNING. On Ohms you connect one lead of your tester to one end of the wire to be tested and the other lead of your tester to the other end of the wire to be tested, with your tester on 200 ohms you should see a reading near to zero.

have yu looked in the Qs and As section for testing an alternator - there is a link there.

right so trace the wires from alternator see where they go and then stick a test lead either side? in any order? red to alternator etc?

i dont know where the q and a bit is?

wrxfifer said:

right so trace the wires from alternator see where they go and then stick a test lead either side? in any order? red to alternator etc?

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It doesn't matter what colour cable goes where from your tester when measuring resistance of cables.
Make sure you get a good contact at both ends and all being well you should read close to zero.

right sorry for being a pain but after closer investigation there i dont see how this is possible?
the 2 wires come from rear of alternator then go straight in to a large wiring duct thats sealed this then runs directly into the ecu but its totally sealed all the way and clipped doen in place?
will i have to fully remove all the ducting and wiring completely to trace them this seems like a big job?

Hi, Apologies for stating the obvious but did you remove the alternator when overhauling the Heads and if so have you plugged the cable back in?
Hope you get it fixed. Cheers