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Discussion Starter #1
Hi Everyone,

I'm an extremely happy new MGF owner and have thus far loved the first 1500 miles with my new toy.

Having managed to correct the EPAS issue via this forum thanks to the handy guide and conduct some other tweaks and maintenance I'm currently flummoxed by the latest issue I'm having.

Everytime I start the car the battery Warning Light doesn't go off until 5 or so mins into the drive at which point it seems to fade and or flicker seemingly in tune with acceleration/revs before finally disappearing and failing to reappear for the remainder of the drive.

The previous owner had the alternator replaced with a newer '3 wire' model less than 6 months ago and this issue wasn't a problem for the first 1000 miles of my ownership (from 70k miles). I have checked and ensure connections are good to the alternator (initially thinking it was a dodgy connection) and the belt looks to be correctly tensioned and in good condition. When idling the voltage across the battery is just under 14V and I've also replaced the battery as well with a Varta Silver thinking this was the issue (previous battery was several years old).

I'm now at the point where I think the issue lies with the battery Warning Light circuit but am clueless where to go next. Would anyone be able to suggest where my next Avenue of troubleshooting might lie?

This forums been a fantastic resource thus far so in any case thankyou from a recent lurker!

Thanks. Jack.
 

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mg_tf
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Hello Jack,
Personally I wouldn’t discount the alternator as being the suspect here. It is not uncommon for aftermarket ones to be of dubious lasting quality. 14v output seems a little bit low to me, but I’m sure other forum members will come along with additional advice.
Do you know if the car been started using jump leads since the alternator has been changed? If so, any chance the leads may have been temporarily connected the wrong way around?
Kind regards,
Austin.
 

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Discussion Starter #3
Hi Austin.

Thanks for your reply. I was hoping I'd get away without having to touch the alternator but it seems that might be the next line of inquiry...! Come to think of it I wasn't able to figure out what brand it was under closer inspection as it just looked generic (like this one http://www.incony.org/webpics/MGF Alternator1.jpg).

In my ownership I haven't had to jump the vehicle (and it's started every time). However, couldn't comment on previous owner as they continued to drive the vehicle for a few months after the alternator replacement. I'm guessing this can mess up the alternator if the polarity is reversed?

Are there any other checks I can do to better confirm the alternator is knackered or is it a case of just replacing it with one of known quality? The only other thought that springs to mind is that I noticed the splash guard across the rear drivers wheel Arch is missing and this issue seemed to present itself after a particularly wet weekend a few weeks ago so potentially this could be the root cause...and I should look to replace this as well?

Thanks. Hoping this doesn't start turning into a money pit as I'm quite fond of the car so far!
 

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mg_tf
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Hello,
If this was mine, I would be tracing a trusted local auto electrician and getting them to check the alternator output. A simple test, and indeed most garages should be able to do this for you, but you will need the services of an auto electrician should the alternator be proved not to be up to par, so maybe better to go down this road first.
The alternator lives in an inhospitable location and using the car in rainy conditions without the plastic splash shield is not best possible practice, so I would be looking for one of these - and it’s fixings.
The alternator should be repairable in the hands of a good auto electrician, so it might be worth first checking with whoever you chose as to whether they would repair it rather than replace it if it is at fault. Find an AE who is prepared to repair it.
Kind regards,
Austin .
 

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As what others have said here get it checked out first. A simple multi meter on the battery can be used to confirm if the alternator is functioning correctly. When the engine is not running the voltage should be around 12v, when the engine is running it should be between 13.5v to 14.8v dependent on the speed of the engine.


By personal experience I stay away from rebuilt alternators. A lot of the times the diode pack/dc rectifier on the rear of the alternator are usually cheap ones from China that rarely last more than 12 months. I had three rebuilt alternators across my old MG ZR and my current Rover 25 none of them lasted past six months with one failing within a week of installation.


I purchased a brand new Lucas one and its been on the car for over three years now with no issue.


Rebuilt alternators are false economy as far as i'm concerned, i would rather get one from the scrap yard than buy a rebuilt one.
 

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mg_tf
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Isn’t Lucas now simply a bought out brand name, and brands replica electrical items manufactured in the aforementioned foreign parts?
 

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Not as far as i'm aware. Its owned by the German company ZF/TRW who are not known for producing crap either.
 

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Rebuilt alternators are false economy as far as i'm concerned, i would rather get one from the scrap yard than buy a rebuilt one.
That's a very strange point of view, we have a local auto electrical shop which if you take in an alternator will change the diode pack (normal unit that fails) put in new bushes & new bearings, clean it all up including a spray paint, they offer a 2 year warranty & charge around £50 for our Rav4 alternator, against £135 off Fleecebay or Eurocarparts, didn't dare ring Toyota. I'd rather have that than some random one in a scrapyard.
 

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That's a very strange point of view, we have a local auto electrical shop which if you take in an alternator will change the diode pack (normal unit that fails) put in new bushes & new bearings, clean it all up including a spray paint, they offer a 2 year warranty & charge around £50 for our Rav4 alternator, against £135 off Fleecebay or Eurocarparts, didn't dare ring Toyota. I'd rather have that than some random one in a scrapyard.

Its all down to preference i suppose and how much you can afford to spend.


I've never had any luck with rebuilt alternators or starter motors. There are too many places out there selling rebuilt units that are no better than ones from the scrap yard due to using cheap parts from China. Scrap yard alternators are generally no more than £20 either, so if it lasts six months its no issue.



I have a brand new Bosch alternator in a box along with all the other spares i had to bring with me when i moved to Canada as parts aren't exactly easy to get here. I picked it up on Amazon for £90 delivered to my old UK address. If you look hard enough you can get new stuff for not much more than you would pay for rebuilt equipment.


I also picked up a complete LUK clutch kit for £59 delivered. Its a good quality part and cheaper than for example a crappy Transmech clutch you can get from Eurocarparts.
 

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To the OP: I would get your battery tested.

Its possible that its losing some charge between the end of one journey and the start of the next, hence your symptoms.

Any half decent garage or battery supplier should be able to do a load test for you free of charge.
 

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mg_tf
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According to the OP’s original post, the battery has recently been replaced with a new Varta one, also the charge light takes a long time to go out - and flickers.
I would still be suspecting the alternator, and getting its output checked as first priority.
 

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rover_25
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Hi Everyone,

I'm an extremely happy new MGF owner and have thus far loved the first 1500 miles with my new toy.

Having managed to correct the EPAS issue via this forum thanks to the handy guide and conduct some other tweaks and maintenance I'm currently flummoxed by the latest issue I'm having.

Everytime I start the car the battery Warning Light doesn't go off until 5 or so mins into the drive at which point it seems to fade and or flicker seemingly in tune with acceleration/revs before finally disappearing and failing to reappear for the remainder of the drive.

The previous owner had the alternator replaced with a newer '3 wire' model less than 6 months ago and this issue wasn't a problem for the first 1000 miles of my ownership (from 70k miles). I have checked and ensure connections are good to the alternator (initially thinking it was a dodgy connection) and the belt looks to be correctly tensioned and in good condition. When idling the voltage across the battery is just under 14V and I've also replaced the battery as well with a Varta Silver thinking this was the issue (previous battery was several years old).

I'm now at the point where I think the issue lies with the battery Warning Light circuit but am clueless where to go next. Would anyone be able to suggest where my next Avenue of troubleshooting might lie?

This forums been a fantastic resource thus far so in any case thankyou from a recent lurker!

Thanks. Jack.
I would remove the earth to engine connection and clean,
connect up ensuring tightness, the worse when wet,
would indicate a problem there.
good luck.
 

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Discussion Starter #14
Thanks everyone for the replies. Strangely enough I had no issues driving around like this for a number of weeks but took the plunge in replacing the alternator and belt myself with a new like for like replacement from eBay. Was about £100 all in and following this mornings drive to work the battery warning light has now disappeared! Fell fairly chuffed for having managed it myself in 4 hours...thats a Saturday morning I could have back but...touch wood it should stay that way. My next port of call was going to be checking the connections and Earth straps around the entire circuit which I wasn't feeling particularly enthusiastic about as everything on this car seems a bigger to get to!

Thanks all!
 

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mg_tf
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Perhaps it me, but am I reading this as ‘.... the battery light went out during the journey’ ? -or did the light go out immediately on start up following fitting the new alternator?
 

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mgf
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I am surprised that changing the belt solved the problem, did you find d that the belt was very loose? I would still check grounds.
 

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Discussion Starter #18
Austin you're quite right. Light went out during the journey. Not immediately upon starting up. Tonight when leaving work she wouldn't start either. I got the dreaded machine gun clicking sound and a flat battery.

I feel as if I'm at my wit's end a bit here. Going to get it recovered and to a garage tomorrow. I just want a reliable car 😭.
 

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mg_tf
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OK, so the light didn’t go out immediately - bad sign to start off with.
EBay and £100 alternators? Um!
I would say the way forward is :-
(1) Get the alternator output checked. ( don’t assume new equals serviceable).
(2) Charge the battery overnight then get its efficiency checked.
(3) Check all battery leads and connections, and all main earthing connectors.
 

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Discussion Starter #20
Right so
1. I've checked the alternator output directly at the alt (+ve to engine block) and across this battery terminals and am getting 14.5V DC with the engine running.
2. Charged the battery up overnight and getting a healthy 12.6V. It was just under 11V when I took it out so definitely dead!
3. I've measured for continuity and voltage drop across the whole circuit using the wiring diagrams and checking all the earth connections, cabling to the starter motor across the starter motor and to the alternator. This highlighted that the battery warning light bulb looks to have blown. Starting the car once the battery was full confirmed this as true as it doesn't light with ignition on or as the engine is started. I've been reading up on this and wondered if this could be causing the alternator not to 'self excite' on shorter less spirited drives and thus the battery depleting itself over several short trips.

It looks like I need a capless 1.2W 286 instrument panel light bulb from Halfords for this and will try replacing and checking that tomorrow. Will see how I get on with that!
 
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