Diodes missing on alternator??

[jayod12b]

Well lads.
Problem with alternator me thinks
third time now,
Volt meter been varying up and down past week,
Then yesterday driving home from work i got this whinging noise battery dropped right down and lights dimmed,

Wudnt start this morning, took the alternator out this evening and i think 1 of the diodes are missing,

Just the whinging noise has me a bit confused,taut it was a bearing inside it but its moves free here

Can anyone help confirm its the alternator before i buy another

Thanks jay

[Sebastian]

OT here but how did you take the alt out ?

[jayod12b]

Hold on sebastian lll go out and get ya a picture, give us a few mins

[Sebastian]

Hold on sebastian lll go out and get ya a picture, give us a few mins

did you just follow advice from here ? ->
http://www.fto-ireland.com/forum/phpBB2 ... php?t=8449

or you have done it easier somehow ?!?

[jayod12b]

Followed that guide pretty much
Removed it through the drivers wheel arch seb,
Put the car on a stand at jacking point
removed the engine mounting bolt so i could jack it up engine separately, Then took out the top 2 bolts of the suspension strut and track rod this give u enough room for it too come straight out.

[CJ]

You can't see the rectifier \ diode pack from the outside, the alternator will need to be disassembled to check the pack. The problem could also be related to the brush assembly, stator or rotor (although rectifier is most often at fault).

The VR-4s alternator gave up the ghost last night so its in being reconned at the minute - must be the time of the year!

CJ

[jayod12b]

Thanks for reply havent tryed to open it yet,
just from the lookin at it ter seemed to be a piece missing

must be the time of the year!

[Dean]

Thats what mine does, but it always goes back to normal.

[jayod12b]

Update on alternator,
It was the diode pack after all,
Got it replaced today, couldnt believe how burnt out it got inside really melted,
Anyways hopefully get it back into the car in the morning and back on the road

[img]http://www.fto-ireland.com/forum/phpBB2/album_pic.php?pic_id=1382[img][/img]

[CJ]

Nice work Jay. I've always though that Mitsi alternators where a bit on the weak side, especially with regard to the diode pack - I've had to have them replaced on 2 FTOs and a Galant....

CJ

[Dean]

how much did it cost you to replace the diode pack?

[jayod12b]

Cj. : yea third time for me to change the alternator definitely a weak side to the fto, hopefully this one will last a good while.

Dean:
Yea dropped it into auto eletricans in town this morning,
Had it ready for me this evening 85 euro.
Maybe a bit expensive im not sure, dont know what these diode packs go for.

[colm_mcm]

does changing the battery for a bigger one have any ill-effects on the alternator?

[jayod12b]

Done know colm never taught of that,
I have changed the battery on mine too a larger one,
You think that could be the cause??

[colm_mcm]

I know too small a battery would cause trouble, I can't think how a large battery would cause extra load unless it was in bad shape and losing charge, putting strain on the alternator.

Just wondering.



EDIT, just saw this, may be of some use?

Premature Alternator Failure


Alternators are not intended to operate at 100% output all of the time. They are intended to be maintenance and support for the battery, not battery chargers. Alternators used constantly as battery chargers will be overworked and fail prematurely. The following is a list of events, in no particular order, which can shorten the life of any alternator:

1. A defective, damaged or constantly discharged battery.
Ø This allows the alternator to act as a battery charger
2. An incorrect battery
Ø A battery that is too small will require frequent charging
Ø Adding an additional "camper" battery requires constant recharging
Ø Under normal conditions, a battery that is considered to be "too big" will not cause any alternator-related problems
3. Corroded battery cable ends and ground straps
4. Aftermarket accessories can over-tax the charging system in two ways. They can exceed specified alternator charging output causing the alternator to operate at higher than normal temperature. Any accessory that requires a "memory" can keep the battery in constant state of low charge overworking the alternator. A few examples are:
Ø Fog/Driving lights
Ø High-output sound systems
Ø Add-on heating or air conditioning systems
Ø Electronic "Rust Evaders"
Ø Any device that requires a key-off keep-alive memory (radios, TV's, etc.)
5. Incorrectly or frequently jump-starting another vehicle
6. Worn or defective electrically operated accessories requiring higher than normal amp rates to operate

7. Poor engine and body grounds
Ø Poor body grounds can cause the headlights to go bright and dim as engine speed changes resulting in unnecessary alternator replacement
8. Loose or worn connections at the alternator
Ø Broken wires or blown fuses can result in unnecessary alternator replacement
9. Drive belt problems
Ø A loose drive belt overheats the alternator pulley and damages the alternator bearings
Ø A defective automatic belt-tensioner causes incorrect belt tension and belt flex damaging the alternator bearings
Ø Alternators being unnecessarily replaced due to misdiagnosed belt noise caused by alternator belts that are defective or contaminated with oil, antifreeze or "belt dressing"
Ø Alternators being unnecessarily replaced due to loose drive belts causing the alternator to operate at reduced output
10. Motor oil or antifreeze contamination inside the unit
11. Loose or worn alternator mounting hardware causing excessive vibration
Ø Other engine-mounted devices such as loose power steering pump bracket can cause noise and vibration to travel to the alternator
12. Leaving off heat shields or fresh air ducts designed to protect the alternator
13. Disconnecting the battery with the motor running
14. A constant battery drain
Ø Defective trunk or glove box circuit
Ø The maximum allowable battery drain on most vehicles is 40-50mA

[jayod12b]

NOT happy,
Got alternator into car today,
Started fine and volt meter at 14 all good till i brought her for a spin,

Mivec not kicking in and she limits at 6,000 rpm
Just after reading this
http://www.fto-ireland.com/forum/phpBB2 ... r+6000+rpm sickened!!

Any other suggestions lads before i start trying to remove this annoyance again?

[Dean]

Done know colm never taught of that,
I have changed the battery on mine too a larger one,
You think that could be the cause??

Hmm.

Mine started around the time I did that too.