MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
  
|
| Help!! Alternator Issue?? |
|
Having an issue with what looked at first as a failing alternator and now I am not so sure.....
So the story goes like this....took my D3 to have its MOT and thought that the voltage at the battery was much higher than I had seen before. With the engine running it was as high as 15.6V and with the engine off the battery was showing 12V.
Dealer did the MOT and at the same time they changed out the alternator. A few days later I had to take my wife to hospital (in the D3), and had to go home and use my daughters car as the LCD cluster in the middle of the dash was flashing at a one cycle/second frequency. Left car on drive.
Next day I started the car in the evening and with the lights on I noticed that when I revved the engine the tail lights were flashing again at a one cycle/second frequency. As the lights were flashing the engine sounded like it was under load at the same one second beat.
So called out LR Assistance, and the chap put a DVM on the battery and he concluded that the alternator was likely to be the issue. So......back to the dealer and they 'diagnosed the fault' and I understand that they changed the alternator again (although I do think they just took the LR Assistance chap at his word and just swapped it out).
Went back to dealer again this morning, and when I got in the car I checked the voltage on the sat/nav display and the highest reading on there was 16V and they were mainly over 15V. Also I turned the headlights on and I could see the rear tail lights flashing again as I revved the engine. Then after a while I notoiced the voltage was fixed at 11V whether I revved the engine on not!!
I then decided to leave the car at the dealer and told the receptionist that the lights were flashing like a police car!
Having now had 3 alternators in the car in the last few weeks, I am beginning to think that there was never a problem with the alternator and that something else is wrong.
Any ideas chaps?
I will call the dealers again on Monday - if anyone else on the forum has any experience as to what may be causing this issue, that may help in my discussions with them.
Many thanks guys,
MG. MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
 11th Feb 2017 4:08 pm |
|
|
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10364
|
you got LED rear lights ?
I have seen my LCD flicker at idle. and goes away once reved slightly. I think it's because the idle speed is so low.
A few people have found the battery earth cable at the inner wing to be loose recently
|
| 11th Feb 2017 4:24 pm |
|
|
Biffysun
Member Since: 09 Jul 2011
Location: Central
Posts: 1787
  
|
 Pretty high readings, what did you use to measure the voltage? was it a genuine alternator or a dodgy copy, some have had problems with 'pattern' replacements 
|
| 11th Feb 2017 4:41 pm |
|
|
MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
|
@Pete K: no LEDs on the car only normal filament type.
@Biffysun: LR Assistance measured with a DVM. I took readings at dealer using the sat/nav Diagnostics Menu - Vehicle Settings gives Battery Voltage.
Is there any control of the alternator by the ECU? Or is it totally up to the alternator what voltage gets applied to the battery?
Just want to get my car fixed now 
Thanks guys.
MG MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
| 11th Feb 2017 5:16 pm |
|
|
geoffsnook
Member Since: 13 Jun 2014
Location: south wales
Posts: 3169
|
Is the alternator a land rover original or a aftermarket number as it does sound as there is a issue with the voltage coming out of the alternator or there is an earth problem if its genuine then probably a bad earth  Discovery 3 se gone
Range rover sport supercharged here:)
|
| 11th Feb 2017 5:45 pm |
|
|
MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
|
I am told by main dealer that it is a Land Rover re-manufactured device. The car is under LR Warranty and I wonder if they are trying to cut costs by fitting cheaper alternators?
I also understand that the ECU controls the voltage/charge rate from the alternator - so could it be an ECU issue, given that 3 alternators all have same over-voltage problem and side/headlights!!
Does anyone know how the ECU controls the alternator? I would love to have at least some small amount of knowledge when I next speak to the dealer. MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
| 11th Feb 2017 6:09 pm |
|
|
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10364
|
Doubt the ecu controls it.
|
| 11th Feb 2017 6:23 pm |
|
|
JMack
Member Since: 02 Aug 2014
Location: Edinburgh
Posts: 1517
|
When you say "dealer" do you mean a franchised Land Rover dealer, some other make franchised dealer or a general second hand car dealer?
I'd be surprised if a LR dealer would fit a reconditioned part.
|
| 11th Feb 2017 7:38 pm |
|
|
geoffsnook
Member Since: 13 Jun 2014
Location: south wales
Posts: 3169
|
The ecu will ask for more power but it does not control it if you switch on anything electric it will ask for more power so i think it is more likely there is a bad batch of alternators or again you have a bad earth as to have 3 faulty ones is hard to believe so you still seem to be not telling us if its a main dealer or a franchise dealer or a main stream car dealer you are dealing with:thumbsup: Discovery 3 se gone
Range rover sport supercharged here:)
|
| 11th Feb 2017 7:59 pm |
|
|
MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
|
Hi Guys
It's a main LR Dealer. Well known dealership.
Is it a smart alternator? I read on a specialist site that smart alternators are controlled by ECU and control the alternator to charge battery to save fuel by loading when decelerating or braking. I believe that this may be a possible cause of the fluctuating voltage which is 'pulsing' the lights. The LR Assistance chap said he could see the voltage changing between 13V to 15.3V while he revved the engine. As you could imagine the brightness of the bulbs would be very visible with a variation of 2.3V. MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
| 12th Feb 2017 1:15 am |
|
|
MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
|
I should have said in previous post - could it be the ECU has developed a fault or has a bad connection?
Just guessing - is it possible to do a health check on ECU using diagnostics analyser? MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
| 12th Feb 2017 1:20 am |
|
|
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10364
|
If it's changing between 13V and 15V
check the alternator fuse under the bonnet.
5A
Sometimes this has to be replaced the first time the alternator is changed 
|
| 12th Feb 2017 11:34 am |
|
|
Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10364
|
Fuse 20 under the bonnet
|
| 12th Feb 2017 11:54 am |
|
|
MG
D3 Decade
Member Since: 08 Nov 2005
Location: Surrey
Posts: 217
|
Hi Pete
Hopefully the dealer will check this. Car has been in 2 days now so may have thought about this fuse. My suspicions are a bad/dirty connector on the ECU board which does control the alternator charge rate and voltage (so I have read elsewhere). The com connector connect to ECU on smart alternators I believe - I am no expert!! Did ohms law at college  )) MG
HSE V6 Diesel
Buckingham Blue
Ebony Leather
Side Steps
Mini Fridge
Rosen A7 Roof-mount DVD player
Parrot 3100 Bluetooth
Removable Towbar and Elecs
Pure Highway DAB
Portable Fridge
|
| 14th Feb 2017 12:40 pm |
|
|
mike23118
Member Since: 01 Oct 2010
Location: North Wales
Posts: 1028
|
Have you had the battery tested , as a goosed one will be asking for more volts from alternator
|
| 14th Feb 2017 2:52 pm |
|
|
