Thread: Td5 alternator

Sounds good. I fear we may and up doing the same as the wife is talking about reconfiguring most of the rooms and knocking walls out. Could be expensive as the whole house is double brick including just about all the internal walls.

How much damage can we possibly do to the house in 18 Months when we'll have to rent it out to fund our big lap?! Well at least I decide what to do to the shed!

Originally Posted by simonmelb

Hi,Resurrecting this thread - I'm looking to improve the output voltage of my alternator (it sits at about 13.8 - 14v when warmed up). The alternator is original and I've given it a good clean an installed new brushes but the regulator is original.Would this one do the job? 14.7V apparently.IN249 Voltage Regulator for Nippondenso ( Denso ) type Alternators - 12 Volt, 14.7 Volt Set PointPS: Reason is my drive to work is only 20 mins and the 2 batteries don't often get a big charge so would like a higher voltage from the alternator.

On the D2 there is a short wire that goes from the 3 pin plug that plugs in the back of the alternator to the main output bolt on the alternator. This wire is the regulation sense wire that the regulator uses to charge the battery at 14.7 volts. If you extend that wire and connect it to positive battery terminal it will make the regulator sense the actual battery voltage , instead of the battery voltage minus the voltage drops in the harness - the more load the more it drops. Remember that the glow plugs on these engines can run for up to 30 minutes depending on ambient temperature , engine load etc...So a cold start with heaters , glow plugs , demisters and heated windscreens and seats on some models can really cause a huge drop in voltage across the harness.Give it a try - all it costs is a small length of wire and some time. If you are careful it can be done without removing anything except for the battery terminal and the main charge wire's retaining nut.

Originally Posted by Sneaky

On the D2 there is a short wire that goes from the 3 pin plug that plugs in the back of the alternator to the main output bolt on the alternator. This wire is the regulation sense wire that the regulator uses to charge the battery at 14.7 volts. If you extend that wire and connect it to positive battery terminal it will make the regulator sense the actual battery voltage , instead of the battery voltage minus the voltage drops in the harness - the more load the more it drops. .

Thanks Sneaky. Welcome to the forum.

So that wire could in theory, be extended and have a fuse/diode style dohicky inserted in it, and then return it to it's usual position .... like the Toyota fuse wire for the alternator trick ... replace fuse with a fuse/diode to drop the "sense" voltage, forcing (on the Toyotas I believe) about another 0.3-0.5v increase .... just what we are looking for ..... ?????

Tell me more .... is it that simple ? Just drop the voltage on that sense wire ... ??

Originally Posted by Fluids

Thanks Sneaky. Welcome to the forum.

So that wire could in theory, be extended and have a fuse/diode style dohicky inserted in it, and then return it to it's usual position .... like the Toyota fuse wire for the alternator trick ... replace fuse with a fuse/diode to drop the "sense" voltage, forcing (on the Toyotas I believe) about another 0.3-0.5v increase .... just what we are looking for ..... ?????

Tell me more .... is it that simple ? Just drop the voltage on that sense wire ... ??

Yes that is correct - the sense wire should be able to be fooled like that. Just remember that the standard regulator is set to 14.7 volts and is temperature compensated. That is the reason why the voltage drops as the car runs longer. When you do a cold start the alternator is cold and the output at 14.7 - as the regulator warms up the max output voltage will drop to 14.1 volts or so. In an ideal world the temperature sensor in the regulator would be on a cable and connected to the battery to get a "proper" measurement of the battery temperature. But I guess for reliability reasons - and lots of other reasons they have it internal to the regulator.


Another thing to remember is that if you disconnect the sense wire and start the car - it will sense an open circuit and switch back to regulating the voltage at the main output terminal - but it will light the alternator light on the dash to let you know there is a problem even though it is charging.

You reading this Simon ?

Yes - now u understand what's happening .

ill do some tests I think ! But will have to wait till we move house and I finally have my own garage :-))

Hi all,
Does anyone know where you can source a diode pack for the TD5 D2a alternator. Denso 100213-2530.
A few months over 2 years old and it has died. One year warranty...not happy !

Local repairers don't carry many parts for these, notably the diode pack.

Cheers, Bill

Originally Posted by blinky64

Hi all,
Does anyone know where you can source a diode pack for the TD5 D2a alternator. Denso 100213-2530.
A few months over 2 years old and it has died. One year warranty...not happy !

Local repairers don't carry many parts for these, notably the diode pack.

Cheers, Bill

Did you try Denso, they don't list anything pre-2006 on the website but you'd like to think they'd have some idea. Phone is 03 8761 1449