Earth points

[HQentity]

Hello all! Hope you’re keepIng well.

My electrics are up the creek (without a paddle!!). For a few months now all my bulbs have been glowing mysteriously brighter when I drive along. They’ll all just pulse brighter for half a second! At first I thought Nina was just enjoying the music and getting a bit excited, but think maybe it’s a bad earth?

Secondly and more frighteningly, my IGN light is now on permanently. It dims a little at higher revs, but the voltmeter always comfortably reads 14v (with everything electrical off 3000rpm, sometimes over-reads). Alternator is <6 months, battery maybe a year old. Fan belt tight.

Thoughts? Where can I get a guide to earthing points please?

[tony g]

It sounds to me like alternator problem again. Its worth checking earths though. Neg of battery should attach to the engine either via a chassis connection or straight to it. On a sprint, one part of the earth connection to the block is via the engine mount bolt on the N/s I think. Also worth remembering is the alternator itself MUST have a good clean connection to the engine too via the bolts from the engine to it. Quick dirty check is to attach a jump lead to the alternator body and the other end to the battery negative. If light goes out it'll be alt to block dirty connection. HTH

Tony

[Galileo]

Silicone diode rectifier pack is starting to break down, which causes over voltage hence lights being brighter and they pulse as the bridge rectifier is no longer intact and so you're getting an AC ripple. You're seeing the ignition warning light on because the normal zero point for the ignition light has been passed, it's normally balanced, but if not due to too little or too much charge it will light up, dimly usually but may get brighter or pulse as well.

Edit: Should say, this is noramly an easy job and cheap to replace if your alternator is otherwise in good condition, for example, assuming you havce the standard alternator: https://www.jcrsupplies.co.uk/products/ ... dvert.html

[Tony Burd]

If you are overcharging which it sounds like, be careful as it can cook your battery.

I had the same problem & on a 2 hour drive back from a show the battery spat acid out of the vent onto my newly painted engine bay!

[MIG Wielder]

Hi Kyle, Remember we had your engine out some time ago ? As Tony says above, one of the important earth points is the one from the battery to the offside engine mount which we had to remove. Did we tighten it back O.K. ?
The other thing to check is since you have an early car ( N-reg ) you may still have the early wiring to the alternator.
This is one thin brown / yellow which is the IGN light connection, one thick brown wire which is the main +13.5V high current output and a third thin brown wire which is the early alternator "sense" output. It would be worth checking the connection of this wire. If it goes open circuit or high resistance the output voltage will go high.
On the other hand if you have 2 thick wires it is a "local sensed" alternator, so back to square one.
The quick solution is going to be swap the alternator for a new one, as the combination of high voltage on the battery gauge with IGN light on is unusual.
Tony.

[HQentity]

Ok so I cleaned up all the connections and earth points I could find (Tony I do have the early connection to the alternator), and the idle has improved & rose a good 300rpm, so clearly helped! Driving into work this morning, no IGN light, but it still appeared there faintly when I parked up at the end after I brought the idle back down to about 800!

Thinking the next best idea is the silicone diode rectifier pack - bloody frustrating though with a new alternator. I’m pretty sure I have a standard alternator, so should be straightforward!

Thanks!

[GTS290N]

There's a reason the spares for the original alternators are so easy to come by.......

[HQentity]

Hiya all again.

My alternator is once again driving me a bit loopy. I replaced the rectifier a few months ago which seemed to improve things, but now she's overcharging again all over the shot. I pulled the alternator to bits and re-soldered the connections, but still no luck.

At the moment, the IGN light comes on when I start up, then disappears and alternator overcharges the moment I put the revs up, accompanied by a quiet whistle from the alternator.

Before I get a new one, does none have any ideas?!

[soe8m]

Try to buy nos Lucas in the red boxes and not use the Chinese Lucas labelled parts in the green boxes.

Jeroen

[MIG Wielder]

Hi Kyle, Sorry about the delay in replying. There are 2 bits of electronicky in the standard alternator. One is the silicon rectifier pack and the other is the voltage regulator. This" looks" at the voltage on the "sense" wire, ( electrically very close in voltage to the battery voltage ) and increases or decreases the field current to regulate the output voltage.
Depending on the alternator it will probably be a "14TR" type regulator.
One other thing I noticed you mentioned is that the alternator is whining. Not good news as this is either the end bearing worn out or it can be a symptom of part short circuited windings in the alternator.
It could be time to lump it in the skip ( = trade it in for a new one) sadly. I think Alun does these but there are always lots in the breakers yards.

Cheers for now,
Tony.

[HQentity]

Thanks for your views guys - I've gone for a new one as I'm hoping that will spell the end of my troubles with it. Hopefully it will be in before the new year.

Many thanks!

[TrustNo1]

wasn't the alternator under warranty?

[HQentity]

wasn't the alternator under warranty?

I think it probably was. I had an absolute nightmare though with "Wins International" - I bought the original from them, and when it went wrong, he begrudgingly gave me a replacement that had no pulley. He was really difficult about everything. I bought 2 pulleys that were supposed to fit, but neither did, so in the end I just gave up. I've used him loads because he's local, I won't be using Win's again, I must say!

[TrustNo1]

wasn't the alternator under warranty?

I think it probably was. I had an absolute nightmare though with "Wins International" - I bought the original from them, and when it went wrong, he begrudgingly gave me a replacement that had no pulley. He was really difficult about everything. I bought 2 pulleys that were supposed to fit, but neither did, so in the end I just gave up. I've used him loads because he's local, I won't be using Win's again, I must say!

Fair comment, I've only used them once before.