Thread: New Alternator/Battery Charging issue.

Hi Garry, have you been for a drive yet?

Being as your battery was flat, and you only put a small charge back into it, the low voltage, if at idle, should be nothing to worry about.

If you go for at least a 30 minute drive, then check the voltages.

I charged the battery up and was charging at 15v - charging light still on - then all instruments and lights shut down while engine running. Going for a drive showed voltage up to 18v so shut down the car. Back home restarted and got all Christmas Tree light dash and various faults showing - typical signs of a faulty alternator.

So pulling it back out. I suspect the connector socket is the wrong way around but will check the connection code on the side of the alt with the connection code on the old alt.

Off to work I go

Garry

Hi again Garry, and with the voltage running at 18, you have what is known as a "Runaway Alternator"

The most common cause of this is either a stuffed regulator or no earth between the motor ( alternator ) and the battery ( body ).

This may well be as you posted, caused by the wrong connection on that plug.

While the 18v is a No-No for your battery, it should not have harmed any of your electronics.

The electronics in all vehicles are actually designed to tolerate a Runaway Alternator.

Thanks - I only had the engine running for about 2 mins on the drive so should not have impacted the battery in that short time - and doesn't seem to have.

Taking it all back out now.

Well I took the alternator back and asked if I could have a Denso as a replacement. They do not have Denso suppliers so the replacement will be whatever turns up. Gone are the days of the customer being able to dictate replacement, repair or money back. As they can provide a replacement I have to take that - but I did stipulate the if this knockoff they supply does the same I will get a Denso and install that and be back for my money back.

The reason I did not go for a Denso in the first place was that I needed my car urgently to deal with family issues so was prepared to take whatever I could get - no Densos were available locally. As it turned out I have had to use my old jag so there is no longer the urgency.

At the moment my local car is my Haflinger and long distance is the Jag - expensive at 15mpg 98 octane.

Originally Posted by 101RRS

At the moment my local car is my Haflinger and long distance is the Jag - expensive at 15mpg 98 octane.

The Haflinger should do better than 30mpg on 91, how much do you value your time and comfort 😇

Tony
(Who owns a Haflinger and has in the distance past has done long(ish) trips in it)

Originally Posted by TonyC

The Haflinger should do better than 30mpg on 91

Dream on - 18mpg on a good day.

You have stated that the battery voltage increased to 13.16V with the engine running, this would not be possible if the output connection on the alternator were incorrect. The fault lies with the Can Bus connector, without removal of the RH inner guard I am struggling to see how that connector could be connected correctly or not damaged during the removal of the original alternator. If you check my posts on the saga I experienced replacing the alternator on my D4 TDV6 you may gain some insight towards a solution.

Originally Posted by 101RRS

This thread follows on from here but is now a different issue Remove 2.7 Viscous Cooling Fan

Last night I finished installing a new alternator in my 2.7 RRS/D3. Before I put the fan on and all the air trunking between the air filter and the intercooler I started the car.

Initially the check engine light and the charging light stayed on but on second and third starts all was good - no faults and running fine.

Because I had all my tools sitting on top of the engine, the bonnet was left open a bit over night and the battery was flat this morning and would not start the car. I put everything else back on and started but the charging light was on but no other fault codes - this is where we started last week.

As the battery was only on charge for 1 hour it was only reading 11.7v but would easily start the car - voltage with engine running was only 13.16v where it would normally be around 14.2 in that situation.

So - do I have a dud new alternator or is there something else in the charging system I need to check. The only odd thing in the alternator installation is the connector on the top back of the new alternator is 180 degrees opposite to the old one - so the clip on the plug goes on the top of the socket of the new alternator rather than on the bottom of the socket. Has the guy making the alternator put the socket in the wrong way around.

I tried to read the codes but the reader is playing up and not reading correctly - maybe the battery voltage is too low for it.

Any thoughts or suggestions from people in know on the issues would be appreciated - guesses just muddy the waters

Thanks

Garry
PS I really do not feel like pulling that alternator out again - if so holes drilled through the drivers inner guard might be the go to access the bottom bolts on the alternator.