Fault in my charging system, I think
Discussion
Rightio, this is a long story so I'll try and keep it brief. Picked up my 1990 Eunos on Thursday. I knew it had a dodgy battery so would need a jump to pick it up, got that sorted. Broke down a couple of times on the way home but eventually managed to get a new battery in it and all was fine.
Fast forward to today, and about 30-40 miles later.
Went to drive back home from Ironbridge at around 10pm (around 15 miles, 2/3rds of which is along country roads with no lighting) and as soon as I put the lights on, the "CHARGE" and "HEAT" warning lights came on on the dashboard, the lights started getting dimmer and the whole car started to jerk violently, losing power catastrophically. Turning the lights off fixed it all and meant I could drive normally, I just couldn't see.
So, there followed a hair-raising drive along 10 miles of country roads at 10pm, with no lights on the car. The only light I had to guide me was the light from the moon (thank GOD it was a clear sky) and the occasional flash of my hazard lights.
(eventually, a car came up behind me, overtook me on hazards and then drove slowly enough that I could follow his lights - he later pulled over and asked if I was alright, and agreed to guide me back home when I told him what was happening, what a top chap!)
So, anyway - the charging system in the car is quite clearly rollocksed. What's the most likely cause? Alternator? Drive belt? Wiring? Why would a faulty charging system stop things like the rev-counter from working properly when that's surely just mechanical? I didn't think it would make the car jerk around either, I thought once the car was started the engine would run entirely under it's own power without the battery being involved.
I'm going to have to try and trickle charge the battery to see if it'll work, I hope I haven't killed the battery stone dead as it's a couple of days old.
Any help appreciated, I really don't want this Eunos to turn into a money pit and I'm worried it's going to
Fast forward to today, and about 30-40 miles later.
Went to drive back home from Ironbridge at around 10pm (around 15 miles, 2/3rds of which is along country roads with no lighting) and as soon as I put the lights on, the "CHARGE" and "HEAT" warning lights came on on the dashboard, the lights started getting dimmer and the whole car started to jerk violently, losing power catastrophically. Turning the lights off fixed it all and meant I could drive normally, I just couldn't see.
So, there followed a hair-raising drive along 10 miles of country roads at 10pm, with no lights on the car. The only light I had to guide me was the light from the moon (thank GOD it was a clear sky) and the occasional flash of my hazard lights.
(eventually, a car came up behind me, overtook me on hazards and then drove slowly enough that I could follow his lights - he later pulled over and asked if I was alright, and agreed to guide me back home when I told him what was happening, what a top chap!)
So, anyway - the charging system in the car is quite clearly rollocksed. What's the most likely cause? Alternator? Drive belt? Wiring? Why would a faulty charging system stop things like the rev-counter from working properly when that's surely just mechanical? I didn't think it would make the car jerk around either, I thought once the car was started the engine would run entirely under it's own power without the battery being involved.
I'm going to have to try and trickle charge the battery to see if it'll work, I hope I haven't killed the battery stone dead as it's a couple of days old.
Any help appreciated, I really don't want this Eunos to turn into a money pit and I'm worried it's going to
Edited by gazchap on Sunday 23 May 00:41
You bought a car with a known electrical fault? I hope you got it at a great price!
I had the exact same failure on a motorbike many moons a go (that was a fun ride, the engine running off the battery only, having to turn the lights off to get enough juice to get off the dual carriageway flyover I was on, engine slowly dying....) - turned out to be a faulty regulator.
Clearly your battery is not being recharged so will be regulator/alternator I guess but I am no expert!
Hope it proves straight-forward to fix
I had the exact same failure on a motorbike many moons a go (that was a fun ride, the engine running off the battery only, having to turn the lights off to get enough juice to get off the dual carriageway flyover I was on, engine slowly dying....) - turned out to be a faulty regulator.
Clearly your battery is not being recharged so will be regulator/alternator I guess but I am no expert!
Hope it proves straight-forward to fix
Edited by bluetone on Sunday 23 May 07:25
I believe the alternator & regulator are a single item - looks like your is faulty.
The whole car effectively runs off of the battery and the alternator is used to keep the battery charged. You can run with a faulty alternator but if the battery dies the car dies. With the battery slowly running out of charge in your case, the sparks would have been getting weaker & weaker. Turning the lights off would have given a bit more power flow to the coils to give you better sparks for a while.
The whole car effectively runs off of the battery and the alternator is used to keep the battery charged. You can run with a faulty alternator but if the battery dies the car dies. With the battery slowly running out of charge in your case, the sparks would have been getting weaker & weaker. Turning the lights off would have given a bit more power flow to the coils to give you better sparks for a while.
gazchap said:
Any chance of the drive belt being the culprit? The previous owner gave me a spare set of belts and i'd rather it was that than a new 350 quid alternator
£350 on an alternator 
I think I paid £65 a couple of years ago for one ,just looked and Euro carparts are £150 so you must be able to get a new one sub £100 Its worth taking a looking to see if the belt is turning the alternator and do you have or can get access to a multi meter to see if it is putting a charge into the battery
MrV said:
£350 on an alternator I think I paid £65 a couple of years ago for one ,just looked and Euro carparts are £150 so you must be able to get a new one sub £100
You are talking about an alternator for a 1990 1.6 Eunos, yeah? I think I paid £65 a couple of years ago for one ,just looked and Euro carparts are £150 so you must be able to get a new one sub £100I just went to Halfords and they want £382 for one. Wouldn't mind sharing the link with me would you please?
[quote]Its worth taking a looking to see if the belt is turning the alternator and do you have or can get access to a multi meter to see if it is putting a charge into the battery
Checked the battery with a multimeter.
Engine off, it was 11.86V. I guess it needs to be higher than 12?
Engine on, but with no electrics, it came down to 11.64V.
Engine on, with the lights on (not main beam, just normal) it came down to 10.75V.
I'm assuming that those latter two figures should be above 14V?
Sounds like it is not working with those readings
Heres the link to Euro's site
http://www.eurocarparts.com/ecp/k/altinator/p/Car-...
If I get time later will try to find some cheaper prices for you
When I got mine it was a case of getting yellow pages out and hunting out a firm that sold reconditioned ones ,they come with a 12 month guarantee so as good as a new one anyway
Heres the link to Euro's site
http://www.eurocarparts.com/ecp/k/altinator/p/Car-...
If I get time later will try to find some cheaper prices for you
When I got mine it was a case of getting yellow pages out and hunting out a firm that sold reconditioned ones ,they come with a 12 month guarantee so as good as a new one anyway
Yes, the alternator should put a strong 14V or so into the battery.
Before you buy a new one - get under the bonnet for a look. I would begin by removing the belt and feeling the alternator spin see if theres any obvious faults - Id also check the terminals on the alternator to see if theres anything obvious thats fried/loose, or if theres a bad connection. Probably worth cleaning up any earthing straps you come across (theres a few on the car, cant remember where0.
Refit a new belt and tension properly, then check it all again. If it is the alternator thats buggered, then as Lazza says, dont buy from Mazda, get a recon/known good one from Autolink or mx5parts of whoever.
Before you buy a new one - get under the bonnet for a look. I would begin by removing the belt and feeling the alternator spin see if theres any obvious faults - Id also check the terminals on the alternator to see if theres anything obvious thats fried/loose, or if theres a bad connection. Probably worth cleaning up any earthing straps you come across (theres a few on the car, cant remember where0.
Refit a new belt and tension properly, then check it all again. If it is the alternator thats buggered, then as Lazza says, dont buy from Mazda, get a recon/known good one from Autolink or mx5parts of whoever.
I wouldn't know what I'm looking for fault-wise on the alternator, so I'm tempted to just drop the £75 on a used one from Autolink and stick that in there
How easy is it to shift all of the hoses etc. away from the alternator so that I can get at it to remove it? I'm a novice mechanic (most complicated thing I've ever done is pretty much changing an ARB on my GT-Four) so don't want to break anything else!
How easy is it to shift all of the hoses etc. away from the alternator so that I can get at it to remove it? I'm a novice mechanic (most complicated thing I've ever done is pretty much changing an ARB on my GT-Four) so don't want to break anything else!
MX-5 Lazza said:
Autolink & MX5 Heaven will do you a good deal on a "known good" 2nd hand alternator 
I just looked up MX5 Heaven and was surprised to learn that it used to be called Bloomsbury Garage. That's really local to me, I did a website for those guys back in 2003.Will definitely get back in touch with them
//edit: Scratch that - the local one is "MX Heaven", not MX5 Heaven. D'oh.
Edited by gazchap on Monday 24th May 13:59
Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff