K Series Charging Issue

[john milner]

2003 EU3 VVC.

Today my red ignition light came on solid and bright when doing about 70mph. No flickering so I assumed the belt had gone. Pulled over and belt was okay and nothing obvious causing the light to come on. Pulled away aggressively and the light went out. A few minutes later it came back on dim but not flickering. Shortly it went out.

When I got home the belt appeared to be tight enough but could do with a bit more to be perfect so I tightened it a bit and then checked across the battery with a voltmeter. I was seeing just under 12.2V with the engine running and revving did not change it. I then turned on the lights etc. and the voltage dropped to under 12V. I checked the alternator casing to the negative of the battery and continuity was good. The light does not come on at all now not even when the engine has stopped. I'm fairly sure I need a new, refurbed or repaired alternator.

If I go for a new one is YLE102430 the modeI should be looking at and where are good places to buy them from? Is there any customisation needed for a bog standard replacement?

http://www.rimmerbros.co.uk/Item--i-YLE102430P

While I'm at it I will also get a turnbuckle type adjuster as the adjuster bolt on mine sheared off a couple of years ago. Any downsides to these?

http://www.ebay.co.uk/itm/MGTF-MG-TF-Upgraded-Alternator-Belt-Tensioner-Adjuster-Bracket-Bolt-Kit-1-/301239576388?hash=item4623472744:g:u5cAAOSwd4tUJpEu

[Wrightpayne]

There was a recent thread on this - Kevsta needed to get one quickly.

[Jonathan Kay]

I'm fairly sure I need a new, refurbed or repaired alternator.

Probably. Most people seem to get good results from local repairers.

But first I'd disconnect, inspect and clean the connections of all the wires to the alternator and all of the relevant fat cables including the engine earth(s).

Jonathan

[revilla]

You can also buy the regulator (which is pretty much the complete electronics including the bushes) e.g.http://www.ebay.co.uk/itm/252421838608 (sorry no links, I'm on Android).

[john milner]

I did consider this but thought If the regulator had blown that would give me an unregulated supply rather than nothing. I didn't know the brushes were included so it is possible that a faulty regulator could stop charging. Is there a way of testing just the regulator or checking the rest of the alternator is okay?

[revilla]

Not really sure, there are still the main rectifier diodes which could be faulty. Take it to somewhere that does alternator repairs and get them to test it for you?

[john milner]

I have found a company about 15 miles away that might be able to help that sell recon units and fix ones they do not stock although I'm tempted to just get a recon alternator from Ebay for £90. I think my next job will be to go through the wiring and try to figure out why the light is now no longer coming on with the engine off as that should prove if something on the alternator is faulty.

[john milner]

It is a Bosch YLE102430. It has made me wonder if an 85A alternator is a good match for a 30A battery.

Cabling is okay (brown/yellow goes to grey plug near front of intake, red/white to ECU, big red to starter).

The red light seemed to go on and off when it felt like it. As well as using a multimeter I also checked the voltages with an OBD scanner. Same results as yesterday with 12.2V engine running and sub 12V with everything on. Revving did nothing to the voltages.

I found a few other tests on You Tube that it passed (one way diode between big live post and casing, resistance across split rings 2.2 Ohms, way more than 5mm of brush). As I don't have enough to isolate anything in particular within the alternator I'll have to get a whole replacement unit or mine repaired.

[Jonathan Kay]

It has made me wonder if an 85A alternator is a good match for a 30A battery.

That's probably a 30 Amp x hours rating and measures the storage capacity, there's no need to match those numbers for charging. What sort of battery is it?

Jonathan

[Jonathan Kay]

I think this is all pointing one way, but I'd check a couple of other things.

The red light seemed to go on and off when it felt like it.

Disconnect the wire to the light at the alternator and connect it to earth. With the ignition on does the red light now come on bright and constant?

As well as using a multimeter I also checked the voltages with an OBD scanner. Same results as yesterday with 12.2V engine running and sub 12V with everything on. Revving did nothing to the voltages.

It sounds as if the wiring and connections aren't the problem, but do the same voltage test at the output terminal of the alternator.

Jonathan

[john milner]

It's a Banner and just a couple of weeks old. I got it after I found the last one flat after a few days off the car and in the garage. With hindsight It is possible I jumped the gun buying it but at the time I figured that it couldn't have long left anyway. The new one certainly turns the engine over with a lot more oomph.

[martinwhitcher]

I'm having exactly the same as you currently, I purchased a new alternator and no change..... checked wire integrity up to emerald and grey engine plug all ok? With the engine running I shorted from live to grey plug brown/yellow wire the alternator was the excited and voltage jumped to 14.4v so the alternator is fine after all...

I need to find out where the feed for the brown/yellow comes from? Does anybody know? Could it be the mfru?

[Jonathan Kay]

martinwhitcher:

Does the battery go flat?

What's the voltage across the battery terminals, and what does the ignition warning light do:

1. With the ignition on and the engine not running
2. While cranking
3. At 3,000 rpm?

Jonathan

[Jonathan Kay]

I need to find out where the feed for the brown/yellow comes from?

1. Do you have the wiring diagram for your car? If not send me a Private Mail.
2. What sort of alternator? If it's a Brise which terminal pattern?
3. The Brown/Yellow wire goes from the appropriate terminal on the alternator to one side of the warning lamp. The other side of the warning lamp is at battery positive. When the alternator isn't charging the lamp sees 12V across it and illuminates. When the alternator is charging the lamp sees very little potential difference across it and doesn't.

Jonathan

[Wrightpayne]

I'd check the large multiplug usually tie wrapped to the engine bay diagonal sort of above steering column. Check the connections are clean and wires sound.

Ian

[john milner]

I believe the brown/yellow goes between the alternator and the red light via the grey plug. The red/white goes to the ECU or at least it does with a standard MEMS3. I'm seeing the same voltages with a meter as I do with a scanner. I use a meter to measure across the battery and I assume the scanner is reading from the ECU so I'm fairly sure my alternator has no output as I'm getting the same result from two sources. My light can come on for a few minutes but still no alternator output so the excitement idea is not working neither does wacking up the revs or engine starting which are other methods that can wake up an alternator.

[martinwhitcher]

I'm finding that the 12v feed is not working as no warning lights are coming on at ignition on mode (apart from a quick flash and then off straight away- I can hear relay click back out again)... for the record I have an aim mlx dash (with aircraft style starter button) so can see voltage etc on the dash. I believe I have a dodgy mfru and the main 12v relay isn't working correctly ( ordered a new one for £16) that should be with me later this week, if this doesn't work then cut the cable ties and go to town with the multimeter. 

Not charging when engine on or off same 12v at battery and alternator also when revved.

[martinwhitcher]

John,

before you go and buy a new alternator, take a wire from the battery 12v positive to the brown/grey wire with the engine running. This should excite the coils and the alternator should work fine as long as the engine is running. If this doesn't work then the alternator is duff.

[martinwhitcher]

Hi Jonathan,

1, yes thanks 

2,Bosch eu3 type

3, yes, though I hope that it takes its feed from the mfru as I've just ordered a new one (£16) so not the end of the world. This could also answer why my oils and pressure warning lights are not coming on at ignition (apart from the flash one - then off along with relay click)??

sorry, I hope this isn't pinching the thread but it does appear that we have the exact same problem?

[john milner]

If the alternator is good then when the light is on that should be enough to excite the coils. A direct link to the battery waking up the alternator would not prove the alternator is good as a direct link should not be needed. I'm not always getting a light when the engine is off which suggests to me there is a problem between an alternator component and ground.

[revilla]

I think you're problem is in the alternator but just for the record, I've seen two K Series cars recently where the warning light just wasn't feeding enough current to excite the alternator into starting normally. Caterham use a warning LED in the tacho rather than a filament bulb. And it's a weedy little LED at that. Measurements on both of these cars (and mine at home for comparison) showed that if you short the alternator warning wire to earth it only passes about 4mA. A 2W bulb would be closer to 150mA. I'm not sure if the tacho is supposed to incorporate a parallel resistor but if it does they must fail regularly! Symptoms of this problem don't match yours though, the warning comes on with the engine stopped and tends to stay on until you give the engine a good revving.

[john milner]

As you have tested three cars but report that only two have charging problems with 4mA would this not mean that the two have an alternator problem and that providing more current is a short term work around rather than a fix? It could even mean that a filament bulb can mask a dying alternator whereas an LED gives early warning.

One thing I did find with a little consistency was that if the light was on that it would sometimes go out at around 2400rpm but come on again a bit higher. I tried this about five times so it may mean something although during other tests the light would not come on at all or would not go out. Whatever I tried though the voltage readings never indicated charging.
 

[john milner]

I've got a replacement alternator and thought that for reference it may be useful to do some basic resistance and diode tests to compare it with the old suspect one.

All tests were all combinations between the four connections. That is earth, big live, small left terminal (lamp) and small right terminal (ECU).

In all tests regardless of polarity the resistance test was infinity (open circuit).

The diode range readings were different:

Old alternator with red lead of meter on earth and black on the big live the reading is 1000+

New alternator with red lead of meter on earth and black on the big live the reading is 350+

New alternator with red lead of meter on lamp connector and black on earth the reading is 1800+

New alternator with red lead of meter on lamp connector and black on the big live the reading is 570+

 

As there is a difference one or both of these alternators is probably faulty. Hopefully I'll find out tomorrow.

[john milner]

New alternator fitted and I now have charging at circa 14.4V.

I have fitted a turnbuckle type belt adjuster and found it much easier to get the tension right. It's not worth fitting one just for the hell of it but something to consider if a new belt or alternator is needed. One problem I had with fitting it is that one of the longer bolts that is supplied is about 3/4" too long and cannot go into the block far enough without bottoming out. My solution was to pack out the bolt head with a few washers but the alternatives are get another bolt or cut the supplied one.