Alternator Advice please:
Discussion
I am having a fwe problems with the lil beastie at the moment and need some advice from you lot who are 'in the know!'
I got a 4.5 99 and have had a nice set of speakers/dvd/amp/sub fitted (which sounds ace by the way!)
The problem i got is starting the car now. I have also had an emerald from Joo (made a world of difference to the car, highly recommended) and have now fitted an cut off switch to the entertainment system.
The car does not want to start too easily unless i use jump leads from another car in which case it fires every time!
I put a voltmeter across the battery terminals the other day and when i revved the car was getting 13.3 and 13.4volts, dropping to 12.something on idle. Is this ok from the alternator? Or does it sound a bit low? Am i right in thinking 14.4v is ideal??
Joo also replaced the 100A fuse and took it off the bodywork to stop the vibration splitting the link.
I am going to get a new battery for the car but if the alternator seems low then would like to sort this at the same time for obvious reasons!
Anyone help please??!!!!! :confused:
I got a 4.5 99 and have had a nice set of speakers/dvd/amp/sub fitted (which sounds ace by the way!)
The problem i got is starting the car now. I have also had an emerald from Joo (made a world of difference to the car, highly recommended) and have now fitted an cut off switch to the entertainment system.
The car does not want to start too easily unless i use jump leads from another car in which case it fires every time!
I put a voltmeter across the battery terminals the other day and when i revved the car was getting 13.3 and 13.4volts, dropping to 12.something on idle. Is this ok from the alternator? Or does it sound a bit low? Am i right in thinking 14.4v is ideal??
Joo also replaced the 100A fuse and took it off the bodywork to stop the vibration splitting the link.
I am going to get a new battery for the car but if the alternator seems low then would like to sort this at the same time for obvious reasons!
Anyone help please??!!!!! :confused:
A happy alternator should produce 13.8 to 14.2 Volts normally, even at idle. However the voltage will be pulled down if the battery is very flat, or there is a heavy electrical load on it. Low battery voltages can be caused by bad earths, or are an early warning of impending 100A fuse failure.
With regard to the starting, it may be worth checking with Joolz that you have the latest issue of the Emerald software. If you don't then I'm sure he can arrange an upgrade for you (recommended). Early versions didn't have battery voltage compensation for the injectors. The newer version does, although is still a somewhat simplistic linear factor (like DTA up to version 33.0 when I last looked).
When you crank an engine, it will always start if it is a bit rich. However if it is lean it will never catch, no matter how long you crank it. This is important since injectors (like ignition coils) are incredibly sensitive to battery voltage.
As the voltage falls, they open more slowly. Hence the open time needs compensation to ensure the same volume of fuel flows. The rule they follow is actually exponential - as an example I have included the compensation factors for a giant Weber injector in the following table:-
Volts Correction(ms)
----------------------
8.0 2.03
10.0 1.22
12.0 0.81
14.0 0.56
16.0 0.39
With the Emerald, the correction is zero at 16 Volts. Since the factor is linear I would recommend using a factor of approximately 160 microseconds per volt. However you can't just switch it on, because it would alter the whole map. That's why you'd be best off seeing Joolz for a quick fettle.
This does leave the issue that on a cold start on a really cold day, the voltage may go down to 10-12 volts. Effectively this drops you down well into the non-linear region of injector operation. However you can work around this to some extent by careful tweaking the coolant temperature compensation. These situations occur when the block temperature is very low, which will drag down the battery voltage.
Just to help (not), battery terminal voltage falls with physical temperature. Just to make things really weird, the required charging voltage increases as temperature falls!
Hopefully this explains why your car starts better with an extra battery on the scene, since you will get a higher voltage....
By the way - this is not intended as a shot at the Emerald. The information is intended to help those of you who have chosen this solution to get the most out of it, so please take it in that spirit. FYI I have learnt stacks about injectors over the last year!
With regard to the starting, it may be worth checking with Joolz that you have the latest issue of the Emerald software. If you don't then I'm sure he can arrange an upgrade for you (recommended). Early versions didn't have battery voltage compensation for the injectors. The newer version does, although is still a somewhat simplistic linear factor (like DTA up to version 33.0 when I last looked).
When you crank an engine, it will always start if it is a bit rich. However if it is lean it will never catch, no matter how long you crank it. This is important since injectors (like ignition coils) are incredibly sensitive to battery voltage.
As the voltage falls, they open more slowly. Hence the open time needs compensation to ensure the same volume of fuel flows. The rule they follow is actually exponential - as an example I have included the compensation factors for a giant Weber injector in the following table:-
Volts Correction(ms)
----------------------
8.0 2.03
10.0 1.22
12.0 0.81
14.0 0.56
16.0 0.39
With the Emerald, the correction is zero at 16 Volts. Since the factor is linear I would recommend using a factor of approximately 160 microseconds per volt. However you can't just switch it on, because it would alter the whole map. That's why you'd be best off seeing Joolz for a quick fettle.
This does leave the issue that on a cold start on a really cold day, the voltage may go down to 10-12 volts. Effectively this drops you down well into the non-linear region of injector operation. However you can work around this to some extent by careful tweaking the coolant temperature compensation. These situations occur when the block temperature is very low, which will drag down the battery voltage.
Just to help (not), battery terminal voltage falls with physical temperature. Just to make things really weird, the required charging voltage increases as temperature falls!
Hopefully this explains why your car starts better with an extra battery on the scene, since you will get a higher voltage....
By the way - this is not intended as a shot at the Emerald. The information is intended to help those of you who have chosen this solution to get the most out of it, so please take it in that spirit. FYI I have learnt stacks about injectors over the last year!
Hi Jason,
Your set up is similar to mine in that I have an Emerald and ICE (came with the car - but no DVD) and I have no problems like what you have been experiencing. Sounds like there is too much load because of your set-up, which is causing your problems. Is it worth trying an uprated battery first?, then take it from there?
Hope all is well otherwise....
Jules.
Your set up is similar to mine in that I have an Emerald and ICE (came with the car - but no DVD) and I have no problems like what you have been experiencing. Sounds like there is too much load because of your set-up, which is causing your problems. Is it worth trying an uprated battery first?, then take it from there?
Hope all is well otherwise....
Jules.
cheers guys, i think checking earth connections and getting a new battery is my first port of call.
I am assuming it has the newer software as the emerald is a relatively new addition to the modifications i have made to it.
Everything is good jules, will be visiting Santa Pod soon again i think, especially as the weather (was) gettin better!! Hope everything is good for you too!!
Jase
I am assuming it has the newer software as the emerald is a relatively new addition to the modifications i have made to it.
Everything is good jules, will be visiting Santa Pod soon again i think, especially as the weather (was) gettin better!! Hope everything is good for you too!!
Jase
What voltage does the battery show at rest.
It should show around 12.4 ~ 12.8
If it's less that 12 - then it's probably shot..
Best take it along to a battery centre who can test it ..
It's entirly possible for a single cell (2v) to fail suddenly .. result - engine will not crank & start but will run if a boost battery gets it started..
It should show around 12.4 ~ 12.8
If it's less that 12 - then it's probably shot..
Best take it along to a battery centre who can test it ..
It's entirly possible for a single cell (2v) to fail suddenly .. result - engine will not crank & start but will run if a boost battery gets it started..
Hi guys,
Jules(Cyclone), i have now even removed the ICE fully from the car and there is no difference. The following voltages have been measured on the car:
.............................At rest.....On startup..At idle
ICE Switched on:........12.7........10.9..........14
ICE Fully Isolated:.......12.7........10.9..........14
ICE Removed from Car:.12.7........10.9..........14
As you can see, there is no difference, and in fact the ICE has been installed for a year now and with the MBE device it never once failed to start, and would always start instantly.
So the ICE and DVD, in my opinion, are not the cause of the starting problems!
Mark,
Thanks for that info, i am quite interested to read about the battery voltage compensation for the injectors..... I wonder??!!!!
Everyone, looking at the various posts it would seem that the battery and alternator look fine to me! I went and purchased yet another new battery yesterday, swapped them over and it made no difference at all. The car did not start and it read 10.9v when cranking the engine!
Talk about frustrating, the car is stunning and quick.... WHEN IT STARTS!
>> Edited by jasonben on Thursday 7th July 08:52
>> Edited by jasonben on Thursday 7th July 08:55
Jules(Cyclone), i have now even removed the ICE fully from the car and there is no difference. The following voltages have been measured on the car:
.............................At rest.....On startup..At idle
ICE Switched on:........12.7........10.9..........14
ICE Fully Isolated:.......12.7........10.9..........14
ICE Removed from Car:.12.7........10.9..........14
As you can see, there is no difference, and in fact the ICE has been installed for a year now and with the MBE device it never once failed to start, and would always start instantly.
So the ICE and DVD, in my opinion, are not the cause of the starting problems!
Mark,
Thanks for that info, i am quite interested to read about the battery voltage compensation for the injectors..... I wonder??!!!!
Everyone, looking at the various posts it would seem that the battery and alternator look fine to me! I went and purchased yet another new battery yesterday, swapped them over and it made no difference at all. The car did not start and it read 10.9v when cranking the engine!
Talk about frustrating, the car is stunning and quick.... WHEN IT STARTS!
>> Edited by jasonben on Thursday 7th July 08:52
>> Edited by jasonben on Thursday 7th July 08:55
Gassing Station | Cerbera | Top of Page | What's New | My Stuff