Strange Alternator Problem

[rob321 0]

Hi guys.

 

My 1989 405 Mi has developed a strange problem with its charging. The battery light stays on but very dimly all the time, even when the engine is not running and the battery discharges. Sometimes it will go bright with the ignition on (like its supposed to be) and charge fine.

 

Any ideas what could be causing this apart from a fault alt ?

 

Cheers.

[jackherer 543]

http://forum.205gtidrivers.com/index.php?showtopic=80354

[rob321 0]

Thanks, I have replaced the wire from the alternator +ve to battery to no avail. What startor motor wire are you talking about?

 

Cheers.

[jackherer 543]

On the 205 the main wire from the alternator connects to the starter halfway along its length before going on to the battery +. The 405 may be different but I know the BX 16v is wired the same way. If it isn't the positive wire it might be the ground, i.e. the main earth wire.

[rob321 0]

Ah, I attached another wire straight from the alternator to the battery, so bypassing the original. Was your no charge light dim when the ignition was switched on? This is whats puzzling me.

 

Cheers.

[jackherer 543]

I don't think mine was glowing with the engine stopped, not 100% sure now though.

 

The other thing to consider is the earth for the instruments, I'm not sure about the 405 but the 205 has an earthing block on the steering column under the plastic shroud.

[rob321 0]

Thanks, I've checked all these things but the problem remains.

 

Do you know which alternators are interchangeable for a XU9J4, it currently has the 80A mitshibishi one on it and finding a replacement is proving very difficult.

[jackherer 543]

205 GTI ones fit on and work fine. They have one less groove on the pulley so you need to use a 205 belt and just leave it on 3 out of the 4 grooves on the crank pulley.

 

No idea about how many amps you need on a 405 though, 80A seems a lot, I imagine you would be fine with less, BX 16valves certainly are.

[rob321 0]

Thanks, I really appreciate your help on this.

 

I've just been messing around, when I put a fresh battery in there it started once and then refused to go again, the solenoid clicks away. May this be the starter motor?

[jackherer 543]

If it happened straight after fitting a new battery I would check the terminals are tight.

[rob321 0]

I've triple checked the terminals and earths, I'll try jump starting it from another car in a min because it was a leisure battery!

 

Does this look ok?

 

Cheers.

[rob321 0]

I just jumped it off another car and it started fine, the battery light was still on though.

[jackherer 543]

That alternator on ebay will work but its hard to say if it will need an 8v or 16v belt, I cant count the grooves from that pic but it can't be right for both despite the listing claiming it is.

[rob321 0]

Cheers mate, I'll order a new belt aswell. They're only a few quid. Thanks again