[Mk2] [Turbo] Alternator charging

[BLZ-8027]

How do you tell with a turbo if the alternator is charging? being as theres no voltmeter

I dont think mine is

[jim55]

put a voltmeter across the batt terminals.it should b in the region of 14 -15 volts (as opposed to less than that with the engine not running -12-13 or so ) not got one??get one !!halfords -less than e tenner(doesnt need to b really good -a cheap one will do basic tests)

[BLZ-8027]

put a voltmeter across the batt terminals.it should b in the region of 14 -15 volts (as opposed to less than that with the engine not running -12-13 or so ) not got one??get one !!halfords -less than e tenner(doesnt need to b really good -a cheap one will do basic tests)

Trip to halfords coming up ,
what would the symptoms be apart from a flat battery?

[jim55]

,
what would the symptoms be apart from a flat battery?

err ,,,,if its goosed itl give the same (or a very similiar reading) wether the car is running or not .if the ccar is totally dead get it jump started and as said a meter across the terminals ,if ure not getting 13-14v its goosed (the alternator that is )(could b a fuse as well but thats another thing )if its not charging check the fuse in the engine bay (theres 3 fuses in the fuse box at the rear of the engine bay)theres an ecu fuse (15a i think)and it wont let the system charge if the fuse is blown .if the fuse checks out ok and ure still getting a low reading >>>>ALTERNATOR GUBBED

[BLZ-8027]

,
what would the symptoms be apart from a flat battery?

err ,,,,if its goosed itl give the same (or a very similiar reading) wether the car is running or not .if the ccar is totally dead get it jump started and as said a meter across the terminals ,if ure not getting 13-14v its goosed (the alternator that is )(could b a fuse as well but thats another thing )if its not charging check the fuse in the engine bay (theres 3 fuses in the fuse box at the rear of the engine bay)theres an ecu fuse (15a i think)and it wont let the system charge if the fuse is blown .if the fuse checks out ok and ure still getting a low reading >>>>ALTERNATOR GUBBED

Cheers ,took the car for MOT today and the battery was flat when he tried to get it off the ramps ,jump started first time,left it ticking over for about 20 mins whilst he wrote the ticket out

On the drive home the wipers were going really slow ,then the hazard lights were flickering,then the ABS light and PS light came on ,all the time the car was struggling to run at low revs ,i needed to really throttle it to keep it going ,pulled on the drive ,left it ticking over with all sorts of electrical things happening ,flashing hazards ,relays clicking ,doors locking

Turned it off and then the battery was flat as a pancake

Oh and the battery is brand new

[BLZ-8027]

Bought a draper battery and alternator tester (its all they had) according to the gadget theres no output from the alternator,

I dont get any warning light on the dash though? could it be something simple,before i strip it out ,being as they are a pain to do

Whats with the fuse mentioned ?if thats gone would it affect anything else ,or is it solely for the alternator?

[jim55]

all the electrical stuff you mentioned is down to the voltage in the battery not keeping up with demand .i had the very same (dim lights/hazards,slow windows/wipers )its all related to your alternator issue ,fix that ,all will b fine and dandy

[BLZ-8027]

all the electrical stuff you mentioned is down to the voltage in the battery not keeping up with demand .i had the very same (dim lights/hazards,slow windows/wipers )its all related to your alternator issue ,fix that ,all will b fine and dandy

Cheers mate im going to check that fuse first just in case

[jim55]

the fuse being blown(if it is)doesnt make a big diff ,the car will still run -just no recharging.i messed about for ages and took the alt out /put it back in /took the car to a auto spark -changed the fuse (at the time i didnt know about it )all fixed so its worth checking ,if the fuse is good and its still not charging then its most likely the alternator itself thats gubbed ,its not that bad to take out /put back in(iv done ita few times )

[-:[KM]:-]

Remember to check the ECU-IG fuse in the engine bay first Trev. A blown little 7.5amp fuse will stop the car charging.

I take it you have an alternator knocking about?

[Steve Horrocks]

you got a reverse light? any lights on dash? speedo working?

there's a common fault of a black/yellow wire that break from fuse box to alt which also feeds these parts. depending on where the break is, they will/won't work. I had same problem few weeks ago. Just ran a wire from fuse box (engine bay) to alt & everything works fine.

http://www.imoc.co.uk/forums/viewtopic. ... t=b+y+wire

Is there anything that you think this could be other than a dodgy alternator?

yes,a broken wire on the alternator multiplug is a lot more common than failed alternators...you must check that first.If i had a quid for every mr2 owner thats gone out and bought a new alternator for no reason

Remove plug from alt,switch ignition on (with battery charged up) and measure the voltages at all 3 alternator plug pins,should be 12v or thereabouts on all three.... if one pin (usually the black/yellow wire) only shows 1 or 2v or nothing at all then it has the usual mr2 wire break issue.

hope that helps.

[BLZ-8027]

Remember to check the ECU-IG fuse in the engine bay first Trev. A blown little 7.5amp fuse will stop the car charging.

I take it you have an alternator knocking about?

Checked the fuse all ok ,i do have another alternator that ive fitted
same result

you got a reverse light? any lights on dash? speedo working?

there's a common fault of a black/yellow wire that break from fuse box to alt which also feeds these parts. depending on where the break is, they will/won't work. I had same problem few weeks ago. Just ran a wire from fuse box (engine bay) to alt & everything works fine.

http://www.imoc.co.uk/forums/viewtopic. ... t=b+y+wire

Is there anything that you think this could be other than a dodgy alternator?

yes,a broken wire on the alternator multiplug is a lot more common than failed alternators...you must check that first.If i had a quid for every mr2 owner thats gone out and bought a new alternator for no reason

Remove plug from alt,switch ignition on (with battery charged up) and measure the voltages at all 3 alternator plug pins,should be 12v or thereabouts on all three.... if one pin (usually the black/yellow wire) only shows 1 or 2v or nothing at all then it has the usual mr2 wire break issue.

hope that helps.

Battery charged overnight and checked voltage at the wiring plug, (live to a pin earth to car body?) and ive got 4 volts at one, and 0.7 at the other two

If anyone has an answer or what to check next ,please give me a ring
07791873788
Ill be outside polishing the car ,at least i can look at it from the kitchen window

[BLZ-8027]

Thanks for the phone call steve
Did as suggested and ran a feed from the fuse box to the alternator

No good still the same reading on the multimeter, and still no charge from the alternator




Back to the drawing board

Can anyone show pictures of where all the earth leads are in the engine bay ,so i can check all those

[PW@Woodsport]

Sounds daft but have you checked your fuses? To have all three power feeds to the alt fail is unheard of,so my money is on a blown fuse or two.

[Steve Horrocks]

ha, like I said dude, best guess, but you need to speak to mr woods! Fuses sound good tho now!

[BLZ-8027]

Ive checked the three in the engine bay fuse box ,and swapped them in case .Ill go round them all tomorrow
Stumped otherwise

[BLZ-8027]

Right ive checked all fuses Front /Middle and Back .none have blown

Does the ECU direct power to these alternator wires ? i thought of swapping that to try

Any other ideas folks ?? Please

[PW@Woodsport]

Ok another check....

Test for power at the white plugs in the engine bay fusebox,test the thick yellow and thick black/yellow (the one you joined the red wire to),with ignition switched on,you should be seeing 12v at both wires at the fusebox.

Test the white/red wire in the fusebox for 12v constant.

The ecu has nothing to do with the alternator.

Get back with those results and lets see if we can sort it.

[BLZ-8027]

Seems to be sorted now ,I replaced all fuses in the front and engine bay just in case ,CJ82 came round and we rewired the black and yellow wire from the fuse box to the alternator making good connections, and i then had 12 volts at all three connectors ,so plugged it all back together and the alternator was showing as charging ,so hopefully all is well now

Thanks to Steve Horrocks ,and PW@Woodsport for their advise and help,
And also for CJ for coming over this morning ,two heads are better than 1

Thanks guys

[Cj82]

no problem buddy still got a head ache from figuring out that bloody alarm lol