Alternator (1 Viewer)

[meps161091]

Hi all,

Another alternator post....or is it?

So driving home the other day probably 45mins into a 1hr journey, gave it some pedel on a straight piece of road which resulted in the battery light and some others coming on

Typical alternator fault, so I went looking at the alternator...no funny noises, seemed to be charging, but when I turned all the accessories on I could smell something was getting hot.

It had melted the output post shroud on the alternator, the battery was now also getting down the 13V with the engine running with minimal accessories on.

So I changed the alternator, no I have 14.7v after start up (after the intake heater cuts out).....which is a bit high for my liking? thoughts?
Seems like good ampage coming out the Alt too...I have been able to measure 90A on high idle, its a 120A so at 2k rpm should be achievable.
It is a non brand, which replaced the previous non brand from Milners (which I am sceptical about now as the original only lasted 13k miles & 11 months).
I should have saved my OEM and reman'd it

So I have checked all fuses, although cant find a few, they must be hidden.

Also the lights havent gone out...so I know there is still a problem but is it:
1. too high voltage, im not sure and cant find any specs on when the ECU/BCM will turn them lights on if the voltage is too high
2. the 3 pin plug on the back of the alternator - maybe one of them wires has broken down

So I went looking at wiring diagrams

This gives a good overview

The 7.5A ALT-S fuse is fine which I believe is suppose to give the alternator a reference of the battery voltage so the regulator can stop charge
The 10A FR-IG fuse I cant find which is given power when the ignition 2 is switch on
The 7.5A MET fuse which looks like it supplies power to the battery light on the dash, but the dash also takes a feed from the 3rd wire of the alternator

Im a bit lost where to check next.
Any pointers, im pretty machanically & electrically minded so

 

[meps161091]

FR-IG I have found is from 2003 onwards which is in the engine fuse box - mine is 2001
MET is the same, but in the internal passenger footwell fuse box, so mine doesnt have that either

 

[2001LC]

Did you check for codes before pulling alternator, and then clear them after replacement.

I replaced a 2 yr old Chinese alternator a few months back, which was overcharging. Replaced with OEM reman corrected issue. Most aftermarkets, are made Chinese junk.

I'm curious as to how the case on your alternator was dented/marred near positive post?

 

[meps161091]

Did you check for codes before pulling alternator, and then clear them after replacement.

I replaced a 2 yr old Chinese alternator a few months back, which was overcharging. Replaced with OEM reman corrected issue. Most aftermarkets, are made Chinese junk.

I'm curious as to how the case on your alternator was dented/marred near positive post?

View attachment 2835325

That was me trying to get the positive terminal off the post, the lugs had melted into the plastic you see there.

I did check for codes before...nothing, I havent checked since though so might do that.
Being an 01 plate I didnt think the ECU had much of a brain for things like this.

 

[white_lx]

The molten stud indicates a high resistance point at the alternator connection. Verify that the crimped eyelet on the output wire at the alternator has good connection? (low resistance / low voltage drop, not corroded etc).

The alternator senses the battery charging voltage through the 'Alt-S' feedback wire. ("Alternator Sense"?). If there is a high resistance / open wire in that circuit, the voltage regulator in the alternator will keep increasing the output voltage till it senses the correct voltage at the battery terminal. You mention the 3-pin connector may have a broken wire? If there is a bad connection / broken wire in the feedback circuit your charging voltage will increase.

There have also been reports here of corrosion in the 'fusible link block'. Did you check that area?