Help with my Battery / Alternator / ECU issue
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Not many rules really, this board being aimed at technical issues, it shouldn't fall foul (hopefully) of some of the more personal issues that can affect forums.
Rule 1 - Is that you need to think very carefully before posting anything technical or asking anything technical relating to the security system of the car - See 'Security Issues' sticky for more info.
Rule 2 - We (MGF Register) do not support copyright infringement and therefore references to CD ROM, PDF versions or paper copies of the workshop manual (for instance) should not be posted on the forum. We don't want to get into trouble and we'd rather sell you a genuine hard copy through our Regalia shop anyway!
Because advice is honestly and freely given in this technical section, much of it will be amateur experienced based, so any information is given in good faith and is not guaranteed as correct.
Help with my Battery / Alternator / ECU issue
Hi guys,
This forum has helped me more times than it should, and I'm really hoping for some help with solving my dead battery issue.
I'm quite sure they battery is fine, however when I fully charge the battery it runs out within a 10 minute drive. It doesn't die over night and seems to hold its charge for a while. This leads me more into the area of the alternator, I've removed it and no concerning noises are there. Belts are fine, and all fuses are still intact. When I replaced my hydrogas spheres I removed my ECU, when I installed it back, the car revved a little higher. I reset the ECU and it corrected the problem, could the ECU not be cooperating with the alternator? How would I check that? Unfortunately, I don't have any multi mentors, I took the negative lead off the battery while the car was running, and it stalled. All wires look okay too.
Everything was fine before it was stored away in a barn for winter, just got it out to replace the hydrogas and ended up with this problem. Open to theories on all components.
Thank you for reading and any help would be appreciated
This forum has helped me more times than it should, and I'm really hoping for some help with solving my dead battery issue.
I'm quite sure they battery is fine, however when I fully charge the battery it runs out within a 10 minute drive. It doesn't die over night and seems to hold its charge for a while. This leads me more into the area of the alternator, I've removed it and no concerning noises are there. Belts are fine, and all fuses are still intact. When I replaced my hydrogas spheres I removed my ECU, when I installed it back, the car revved a little higher. I reset the ECU and it corrected the problem, could the ECU not be cooperating with the alternator? How would I check that? Unfortunately, I don't have any multi mentors, I took the negative lead off the battery while the car was running, and it stalled. All wires look okay too.
Everything was fine before it was stored away in a barn for winter, just got it out to replace the hydrogas and ended up with this problem. Open to theories on all components.
Thank you for reading and any help would be appreciated
Re: Help with my Battery / Alternator / ECU issue
I would suggest that you invest £10 in a Multimeter to check battery voltage across the terminals and clamps with and without the engine running. Clean all the connections specially the earth terminals.
NEVER run an alternator without it connected to a battery. It will damage the circuit.
Geoff.F
NEVER run an alternator without it connected to a battery. It will damage the circuit.
Geoff.F
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Re: Help with my Battery / Alternator / ECU issue
A tenner? Spendthrift!
http://www.ebay.co.uk/itm/191921991924
Got one of those the other day as a spare, seems to work fine and it's reasonably accurate.
http://www.ebay.co.uk/itm/191921991924
Got one of those the other day as a spare, seems to work fine and it's reasonably accurate.
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Re: Help with my Battery / Alternator / ECU issue
If the alternator isn't charging the battery, the electronic power steering (assuming the car has it) will flatten the battery very quickly when driving.
If the rectifier on the alternator has failed its unlikely you will be able to tell from looking at it.
As Goeff has said, a quick measure of the battery voltage with/without engine running will show if its charging, not charging or overcharging (will can damage the battery).
Its unlikely the issue is anything to do with the ECU.
FWIW we recently completed 35 miles/1hr journey in a TF with a fully charged battery (and a spare in the boot JIC) and an alternator that wasn't charging, just by removing the EPAS fuse and turning off anything electrical not essential (radio, cabin fan etc)
If the rectifier on the alternator has failed its unlikely you will be able to tell from looking at it.
As Goeff has said, a quick measure of the battery voltage with/without engine running will show if its charging, not charging or overcharging (will can damage the battery).
Its unlikely the issue is anything to do with the ECU.
FWIW we recently completed 35 miles/1hr journey in a TF with a fully charged battery (and a spare in the boot JIC) and an alternator that wasn't charging, just by removing the EPAS fuse and turning off anything electrical not essential (radio, cabin fan etc)
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Re: Help with my Battery / Alternator / ECU issue
Disconnecting the negative lead while the engine is running will toast the alternator.
willyphixitt
willyphixitt
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Re: Help with my Battery / Alternator / ECU issue
Steve White wrote:
FWIW we recently completed 35 miles/1hr journey in a TF with a fully charged battery (and a spare in the boot JIC) and an alternator that wasn't charging, just by removing the EPAS fuse and turning off anything electrical not essential (radio, cabin fan etc)
Steve that is worth a huge amount for me to know. If an alternator belt ever breaks Step One is to remove the EPAS fuse.
Like a lot of things, obvious when you know but not so obvious until you sit and think about it.
In this great wide land down under help could be a lot more than 35 miles away, though most of the F's don't leave the populated areas
there are still some big empty stretches..
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Re: Help with my Battery / Alternator / ECU issue
If the battery has gone flat several times it will stop holding charge unless you get it reconditioned, I got a Ring battery reclonditioner for under £50 and have saved several seamingly dead batteries with it.
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Re: Help with my Battery / Alternator / ECU issue
Thank you so much for your help so far, the Epas fuse is a very interesting thing to know!
I've put the battery on a different car and drove two hours without fault, so I can eliminate that.
I'll buy myself a multi meter today, is there a way of checking the alternator off the car? Or ECU?
Thanks again!!
I've put the battery on a different car and drove two hours without fault, so I can eliminate that.
I'll buy myself a multi meter today, is there a way of checking the alternator off the car? Or ECU?
Thanks again!!
Re: Help with my Battery / Alternator / ECU issue
All fixed!
So it was my alternator all along, I took it off to be tested at an auto electricians to which he comfirmed that it was no longer charging the battery. I have a donor mg, so I took the alternator off that swapped some bits between them and put it on the good mg. £25 well spent.
Always good to have a donor when you own an mg haha
Thanks for all your help guys!
So it was my alternator all along, I took it off to be tested at an auto electricians to which he comfirmed that it was no longer charging the battery. I have a donor mg, so I took the alternator off that swapped some bits between them and put it on the good mg. £25 well spent.
Always good to have a donor when you own an mg haha
Thanks for all your help guys!