Dash warning lights remaining on after new alternator fitted??

[Ciderman]

Hello fellow 80'ers,

A couple years ago i was finding my batteries were flattening down overnight, and decided to replace the alternator.
That cured the problem, and obviously had a bad diode or rectifier unit etc.

However, ever since that, every time i start up - all the dash lights remain on for anything up to a minute unless I give the throttle a quick tap.

Interestingly, if I don't tap the throttle, I've noticed there's a relay clunk somewhere in the engine bay that coincides with the lights finally going out.
I suspect it's the glow plug heater system timer - but the lights do this annoying thing whether hot or cold when starting the engine.

I swapped the alternator for a non-original unit but a new, not remanufactured or refurbished one.
Oval plug, and on a 1993/94 12 valve 1-HDT engine.

Never had a flat battery issue since, just this annoying dash lights thing.
Anyone else had a similar thing happen or know what it could be?

 

[Dave2000]

Assuming the belts are not slipping, then either your idle is too low or your alternator has a low output at idle, true the glow plugs draw a collective amperage of 40+ amps, and the 'clunk' is almost certainly the relay, you don't say if yours is a 12 of 24 valve engine, the 24 valve engine has a heater matrix, the relay is known for overheating and shorting out.

If I had to take a bet I would go with an ageing alternator or very slow idle.

Regards

Dave

 

[Dave_S]

Have you checked the output from the alternator on idle? Per Dave2000's point, the new alternator might just be a bit weedy...?

 

[Ciderman]

Hi Dave,
Its a 12v engine, 1-HDT.
The alternator is, or was brand new and has done this from day one after replacing the original that had failed diodes or internal gubbins, causing the batteries to drain over night.
Charges fine, belts are tip top, idle is spot on and apart from the multitude of dash lights staying on, all is great.
If it was just the battery charge light staying on longer, I'd be happy enough - but it's the whole lot (all the lights you see when tur ing the ignition on pre-start up).
When the clunk of the glow plug relay goes, the lights all go out - or giving the engine a quick rev up.

Could just be a thing I have to live with, but maybe something related to a on genuine alternator.
I've still got the old one so will try and get a new rectifier and exciter brush kit and give it a refurb.
See if that is the issue.
Not even sure what amps the new alternator is, as I understand there's about 3 different output sizes....

 

[Ciderman]

Not physically checked with a meter, but the volt meter on the dash reads good.
As said, it's a new pattern part one and not a denso direct replacement.
Volts will be ok, but perhaps its a lower amp type?

 

[Gav missin]

Give the plug a good clean out and a wiggle .

 

[Dave2000]

Good point, forgot that.

It's amps that charge the battery pushed by the volts, if the regulator in the alternator is poor (unlikely), then I would borrow an alternator from someone, just to check there is nothing wrong. And a aha moment, check the battery connections /fusible links, alternator is IIRC the voltage 'sensing' type, so a bad connection at the battery could cause the alternator be lazy until you increase revolutions?

Re outputs, there are a variety of outputs available, the stock HDJ80 was 80 amps, later versions had 100 amp and I have heard of 110 amp outputs, if you have lots of mods and need more power then you can fit a Sequioa alternator which is available in 130 and 150 amp outputs, getting the version with the oval plug means it will connect the primary wires ok, the square plug version should not be dismissed as it is easy enough to swap the plugs, the pulley needs swapping and you need to increase the output cable size.


Regards

Dave

 

[Ciderman]

Excellent advice!
Ill give it a bit of a looking at and try all you've said here.
I've just ordered a new rectifier, regulator and brush carrier for the old OEM alternator.... Will resurrect that one and see if it makes a difference.
Thanks again folks!!

 

[essexpete]

I had my original alternator repaired and it does sometimes need a throttle blip to kick it off.
I realise the OP has a 12v but the comment on the 24v heater is worth noting. I had a problem with charging years ago and a massive draw on first start up until a click was heard. The alternator could not cope with the draw. It took me ages to realise what was wrong and when I did I simply disconnected the heater. That was years ago.
Going back to alternator, I would suggest that if the old original can be effectively repaired, that might be a better option than a cheap replacement.