Alternator Issues - Help
Discussion
Had a replacement Alternator from the US arrive last week...
It arrived with a WHACKING charge of nearly 60 quid from dear old Customs, on what was an item costing around $150 dollars...and it is a warranty replacement, so already paid VAT and all that before!.....and so I have had to shell out and appeal.
Then – got the thing on the bench and.....
The original was 145amp output VALEO ALTERNATOR for my LS7
The one JS sent is 100 amp Bosch and the bracket holes are not quite the same
..and the pulley is a fair bit smaller!
It is quite a challenge trying to find what it should be for an LS7...
Is 100 amp enough..really? Should I attempt to fit this one - leave or change pulleys?
Advice please! Where can I get a suitable unit in the UK if this one is not really correct?
I am done with the import thing!
yours - Mr very-fed-up!
It arrived with a WHACKING charge of nearly 60 quid from dear old Customs, on what was an item costing around $150 dollars...and it is a warranty replacement, so already paid VAT and all that before!.....and so I have had to shell out and appeal.
Then – got the thing on the bench and.....
The original was 145amp output VALEO ALTERNATOR for my LS7
The one JS sent is 100 amp Bosch and the bracket holes are not quite the same
..and the pulley is a fair bit smaller!
It is quite a challenge trying to find what it should be for an LS7...
Is 100 amp enough..really? Should I attempt to fit this one - leave or change pulleys?
Advice please! Where can I get a suitable unit in the UK if this one is not really correct?
I am done with the import thing!
yours - Mr very-fed-up!
in my case with the Bosch Motorsport alternator the charge signal D+ of the alternator is wired via a resistor to 12V (alternator output or battery 12V), I could measure it for you on my alternator but would assume that a 1000 ohm would be ok. Let me know and I can do it later.
Edited by spatz on Monday 18th October 12:35
I may have to give up on the ECU E38 - since the indication is that the circuit controlling the alternator may be damaged due to the original faulty alternator possibly. The first alternator screwed with the 5v reference lines dropping them significantly and there is no resistance at all on the orange and grey wires to the alternator where there should be (I am told)any more.
And so, looks like either I find a replacement ECU and get remapped or rewire the new lower amperage alternator without any connection to the ECU - shame!
And so, can anyone help me to understand how to do this?
cheers
keith
And so, looks like either I find a replacement ECU and get remapped or rewire the new lower amperage alternator without any connection to the ECU - shame!
And so, can anyone help me to understand how to do this?
cheers
keith
Edited by V8 Vum on Monday 18th October 08:41
http://www.bosch-motorsport.de/pdf/components/alte...
I am unable to measure the reistor value because it is all sealed with glue. I would try a 1 kohm which would be 120 mA which equals a bulb of 1,2 Watt. not much can happen give it a try and see if you have a charge.
I am unable to measure the reistor value because it is all sealed with glue. I would try a 1 kohm which would be 120 mA which equals a bulb of 1,2 Watt. not much can happen give it a try and see if you have a charge.
Edited by spatz on Monday 18th October 12:35
Hi Spatz,
Thanks for trying to help me. Much appreciated.
Bit sad this alternator thing is causing so much trouble.
And so, I presume we are talking about a 1 wire system to kick the alternator into life?
Now, I am extending the OBDII plug from the ECU into the cockpit, and it has an orange light (ign light?)which goes out when the car has started. Is it possible I could use this, or would I run into problems?
I don't see any other source to do this with, and an ign light would be useful in the cockpit anyhow?
What do you recon? ..or is there a better way?
cheers
Keith
Thanks for trying to help me. Much appreciated.
Bit sad this alternator thing is causing so much trouble.
And so, I presume we are talking about a 1 wire system to kick the alternator into life?
Now, I am extending the OBDII plug from the ECU into the cockpit, and it has an orange light (ign light?)which goes out when the car has started. Is it possible I could use this, or would I run into problems?
I don't see any other source to do this with, and an ign light would be useful in the cockpit anyhow?
What do you recon? ..or is there a better way?
cheers
Keith
Hi Keith,
you cannot use the LED at the OBDII plug, it´s the MIL (Malfunction Indicator Lamp)
controlled by the ECU.
It goes out to indicate that no DTCs are set (means no errors).
As Spatz said you can check the alternator by connecting a resistor of ca. 1 KOhm or a 12V, 1.2W bulb to the alternator`s pin where the orange line (turn on signal) from the ECU was connected.
Connect the other side of resistor or bulb to +12V. When the engine runs you should measure approx. 13,5 V at the battery. If you use a bulb you have a charge indicator as it will go out when the alternator charges.
Try it with the old alternator first, maybe it is ok.
Should work unless the alternator has some unusual voltage regulator inside.
As far as I know the LS7 factory setup does not use the ECU to connect the alternator.
Maybe someone who has this setup can explain how the alternator is connected.
By the way, would be interesting to know the Bosch part number of the alternator JS sent you.
Michael
you cannot use the LED at the OBDII plug, it´s the MIL (Malfunction Indicator Lamp)
controlled by the ECU.
It goes out to indicate that no DTCs are set (means no errors).
As Spatz said you can check the alternator by connecting a resistor of ca. 1 KOhm or a 12V, 1.2W bulb to the alternator`s pin where the orange line (turn on signal) from the ECU was connected.
Connect the other side of resistor or bulb to +12V. When the engine runs you should measure approx. 13,5 V at the battery. If you use a bulb you have a charge indicator as it will go out when the alternator charges.
Try it with the old alternator first, maybe it is ok.
Should work unless the alternator has some unusual voltage regulator inside.
As far as I know the LS7 factory setup does not use the ECU to connect the alternator.
Maybe someone who has this setup can explain how the alternator is connected.
By the way, would be interesting to know the Bosch part number of the alternator JS sent you.
Michael
I have edited my above posts, so no confusion there my BOSCH alternator has the resistor connected to the output terminal, which is connected to the battery 12V+.
My Dash unit DIGIDASH will show me the exact charge voltage (actual voltage) when the engine is running, so no need for an indicator light in the dash. If you use a voltage meter or a similar dash the charge light is mood and redundant. Everything above 13V indicates your battery is charging.
My Dash unit DIGIDASH will show me the exact charge voltage (actual voltage) when the engine is running, so no need for an indicator light in the dash. If you use a voltage meter or a similar dash the charge light is mood and redundant. Everything above 13V indicates your battery is charging.
Edited by spatz on Monday 18th October 12:39
I have a JS supplied LS7, ECU and loom. I went my own way the alternator.
I have it wired with a charge light, fat wire to the battery and a wire to the ECU. The engine runs the same whether the alternator is connected to the ECU or not. If you don't want a charge light in the cabin you could fit one in the engine bay.
Watch the pulley size, alternators are not usually designed to run over 15,000 rpm which is easy to achieve with the large crank pulley on an LS7. My first fitment resulted in the cooling fins coming off the alternator, when I calculated the rpm it was close to 25000 at 7000 engine rpm. If you use google you can find an pulley calculator that will give you the figures you need.
You should be fine with 100 amps. You have a fair bit of leeway with the ECU, it will run until the voltage drops just under 10 volts.
Hope that helps.
I have it wired with a charge light, fat wire to the battery and a wire to the ECU. The engine runs the same whether the alternator is connected to the ECU or not. If you don't want a charge light in the cabin you could fit one in the engine bay.
Watch the pulley size, alternators are not usually designed to run over 15,000 rpm which is easy to achieve with the large crank pulley on an LS7. My first fitment resulted in the cooling fins coming off the alternator, when I calculated the rpm it was close to 25000 at 7000 engine rpm. If you use google you can find an pulley calculator that will give you the figures you need.
You should be fine with 100 amps. You have a fair bit of leeway with the ECU, it will run until the voltage drops just under 10 volts.
Hope that helps.
I have been mithering about my charge problem with the LS7 wondering if there is something I have missed. Yes I know I can rewire avoiding the ECU and do it that way with bulbs and resistors, but I would like to get to the bottom of why the alternator does not kick-in just using the ECU two-wire (orange and grey) arrangement.
Then I remembered that when I first installed the ECU loom there was a wire I did not know what to do with, amongst the some others (tacho, speedo etc) that was labelled by someone as:
12 volt for A/C request
which on subsequent enquiry back to my engine builder I was told were not needed!
This wire is 'pink'! This is odd, since the loom I understand was built with the Ultima conversion in mind, so why have a wire added that does nothing?
I know it is a long-shot, but I am wondering if this has been mislabelled and should be:
12 volt for ALT request? becuase it has been written in handwriting and one could misconstrue the 'l' as a slash and the 't' as a 'c'.
The reason is that for the alternator to kick-in it needs to measure the 12 volt line to see if it drops below a certain level.?
I might be entirely wrong, however I wondered if anyone could shed light on this, as I cannot see how the alternator can start charging until it can see the 12volts being lower that its threashold, and maybe this wire I found is the answer????
cheers
keith
Then I remembered that when I first installed the ECU loom there was a wire I did not know what to do with, amongst the some others (tacho, speedo etc) that was labelled by someone as:
12 volt for A/C request
which on subsequent enquiry back to my engine builder I was told were not needed!
This wire is 'pink'! This is odd, since the loom I understand was built with the Ultima conversion in mind, so why have a wire added that does nothing?
I know it is a long-shot, but I am wondering if this has been mislabelled and should be:
12 volt for ALT request? becuase it has been written in handwriting and one could misconstrue the 'l' as a slash and the 't' as a 'c'.
The reason is that for the alternator to kick-in it needs to measure the 12 volt line to see if it drops below a certain level.?
I might be entirely wrong, however I wondered if anyone could shed light on this, as I cannot see how the alternator can start charging until it can see the 12volts being lower that its threashold, and maybe this wire I found is the answer????
cheers
keith
v simply alternator produces a voltage say 14v if voltage in loom is lower than that then current flows into loom/battery. if not nothing flows. ignition light has live on dashboard end. alternator end is earth if alternator not charging. so electricity flows lighting bulb. when alternator charging live on each end so bulb goes out coz no current flows. 3rd wire allows you to sense voltage at point in loom where big current is used and so allows for voltage drop in loom. Hows this fits into the LS7 loom I have no idea!!!
Keith,
could not read the forum over the weekend, was too busy driving the car for the first time :-)))))).
I will have a look at the manual what the pink wire is for.
I don`t think it has something to do with the charging system.
To generate a voltage you need to move a conductor through a magnetic field.
The usual AC alternator does not have a permanent magnetic field, it is generated by coils and a currrent flowing through them.
To "start" the alternator you need to create a magnetic field by suppling some voltage to these coils first.
This can be done by a bulb, a resistor or via the ECU.
With this small field the alternator begins to generate voltage (and consequential a current) that then generates the magnetic field (self-energizing) until the alternator stops rotating.
As the voltage rises with rpm a voltage regulator is needed to limit the voltage to approx.14 V.
The alternator always charges the battery if the battery voltage is lower than the voltage the alternator generates.
Cheers
Michael
could not read the forum over the weekend, was too busy driving the car for the first time :-)))))).
I will have a look at the manual what the pink wire is for.
I don`t think it has something to do with the charging system.
To generate a voltage you need to move a conductor through a magnetic field.
The usual AC alternator does not have a permanent magnetic field, it is generated by coils and a currrent flowing through them.
To "start" the alternator you need to create a magnetic field by suppling some voltage to these coils first.
This can be done by a bulb, a resistor or via the ECU.
With this small field the alternator begins to generate voltage (and consequential a current) that then generates the magnetic field (self-energizing) until the alternator stops rotating.
As the voltage rises with rpm a voltage regulator is needed to limit the voltage to approx.14 V.
The alternator always charges the battery if the battery voltage is lower than the voltage the alternator generates.
Cheers
Michael
Hi Michael,
Sounds like you were in heaven then! Can't wait for my 'inaugural' (blimey! how do you spell that!) drive...depends though on progress this and next year!
OK, got fed up thinking about it, so did exactly as you suggested over the weekend - made up a bridge wire with 1k ohm resistor and connected from the +ve post charging terminal to the orange (charge request)wire in the connector, and all ran as expected with charge working.
BUT, I am a tad worried that this will mean that it is charging all the time? I don't want to cook the battery, so how can that be sorted!
I looked up masses of stuff on the internet and came across some diags that show the 4th pin on the connector to the alternator being used on an LS truck install with a GM ECU (don't know what version). Pins two and three were going back to the ECU via orange and grey as per the LS7 and E38 like mine, but in tbis case they had used pin 4 direct back to the battery via a big fuse, and this was explained as the curcuit that will monitor the charge stage of the battery, so presumably will regulate and thus stop overcharge...
....and so I thought, GREAT...I will do that,...but then on checking the pin-outs on the supplied alternator from Jeff via any docs I could find on the web, it always said 'NOT USED', so I cannot confirm if this pin 4 thing would work, and I don't want to take the risk!
Frankly the orange and grey wire to the ECU 'appears' to be doing nothing at all, but then I have no clue!
Anyone can shed some light on the above?
cheers
Keith
Sounds like you were in heaven then! Can't wait for my 'inaugural' (blimey! how do you spell that!) drive...depends though on progress this and next year!
OK, got fed up thinking about it, so did exactly as you suggested over the weekend - made up a bridge wire with 1k ohm resistor and connected from the +ve post charging terminal to the orange (charge request)wire in the connector, and all ran as expected with charge working.
BUT, I am a tad worried that this will mean that it is charging all the time? I don't want to cook the battery, so how can that be sorted!
I looked up masses of stuff on the internet and came across some diags that show the 4th pin on the connector to the alternator being used on an LS truck install with a GM ECU (don't know what version). Pins two and three were going back to the ECU via orange and grey as per the LS7 and E38 like mine, but in tbis case they had used pin 4 direct back to the battery via a big fuse, and this was explained as the curcuit that will monitor the charge stage of the battery, so presumably will regulate and thus stop overcharge...
....and so I thought, GREAT...I will do that,...but then on checking the pin-outs on the supplied alternator from Jeff via any docs I could find on the web, it always said 'NOT USED', so I cannot confirm if this pin 4 thing would work, and I don't want to take the risk!
Frankly the orange and grey wire to the ECU 'appears' to be doing nothing at all, but then I have no clue!
Anyone can shed some light on the above?
cheers
Keith
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