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2002-2005 Range Rover MkIII / L322
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Discussion Starter #1
2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

Hi folks.

Im pretty stumped now.

L322, 4.4V8, 2003.
Low charging voltage was original symptom. Creating random fault codes due to low voltages (or so I assumed). I was unable to read any of the units, apart from the ECM. I was seeing a CAN BUS time out or failure to communicate with the modules.
Trans failsafe was showing, along with inactive air Suspension. Car started and drove fine, with the exception of the Gearbox only allowing 1-4 ad not going into 5th or locking the TC.

At idle the original voltage was 13.8v with no load.
Little change at 2000 Rpm
Lights and heater/heated screen on at idle and it was down to low 12v roughly.

I took the decision to change out the alternator and Battery for good measure as it was a cheap brand battery that was fitted.
My hope being the low voltage was the cause of my communication issues between diagnostics and Vehicle.

Diagnostic tool is the Hawkeye , for info.

I went with a Bosch replacement for both items. Alternator being a re con unit from Bosch as new are apparently not available any more.

New Battery and Alternator fitted and the problem was not improved. Perhaps if anything, the idle voltage increased to 14.1v, but still the same when loaded.

All cables checked for voltage drops. Negligible over Negative from Battery to Earth points under the hood , including the alternator body.
Negligible on Live side either. 0.3 V was the most I saw on the positive side.

Checks carried out on the Live terminal on the Alternator and the alternator body as the earth tied up with the voltage drop found on the cable runs.

I should add that I was still unable to communicate with the Vehicle via the Hawkeye.

I had hoped that the Alternator fitted was faulty, so got another from the Supplier.

Very much the same readings from this unit. Again, this is a Bosch re con unit.
However, I was now able to communicate with the vehicle and all comms issues were gone, allowing me to clear all Faults.

Spoke to the Supplier again , along with a couple of LR specialists in the UK. Specialists agreed that the alternator was the issue. Its a simple charging circuit and nothing fancy is controlling the output from the Alt.

Supplier now tried another brand of Alt.

I have fitted this one and it is better. Im at 14.1 to 14.2 at idle with no load.
I put lights on and it maintained this voltage.

Left the vehicle to warm up with the fresh coolant in it and loaded her up with fan and heated screen. 12.5v now.

After having let the vehicle sit for a few hours I went back and started it up again.
14.1 v at idle.
Headlights on 13.1.

After 15 min the voltage has now dropped to 13.5v at Idle
Headlights on 12.5V

Im now at loss as to where I go now. It seems like the Alt performance drops with the increase in Engine Temp.

The Multiplug on the Alternator. One wire should be 12V from Ignition to Excite the ALterator. This checked out healthy. Voltage the same as what the battery is giving. Give or take 0.2 volts
The second wire, the signal back to the ECM is getting roughly the same Voltage.

I have never been as low as 11.4v to find out if the ECM is seeing this signal from the Alternator. To see if engine RPM would increase.
However, I did remove the Multiplug from the Alt while the engine was running and I got no RPM increase. I also did not get the Battery light to come on at this point, which I dont understand.


So, where am I going now then ?

I don't see anything that controls the V output from the Alternator that is external . Its an internally controlled output from what I understand.

Surely I cant have had three faulty alternators!!! However, I would say that it is the case.


Have any of you guys had the same issue by chance, or has anyone got a better understanding of how these charging systems work?

I served my time as a Mechanic and this kind of issue was easily resolved with an alternator replacement in every case. Im ashamed to be struggling with this one! However, I may be loosing my touch after too many years away from the tools!

Advice greatly appreciated.

Regards

J
 

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I'm on my second alternator and still seeing fluctuations. Probably the cause of my hdc suspension inactive brake lights. My battery is fairly new and tested out in good condition. What's going on here! Corrosive wiring to/from alternator?
 

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Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

FWIW, I had almost identical issues with my '04 - even after replacing the alternator (twice). My problem turned out to be a fault in the section of wire going from the alternator to the lug at the back of the engine. Check and double check voltage drops at every connection. Hopefully you'll get lucky and find a fault as I did.
 

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Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

Thanks for the response. Do you remember how you were able to reach this wire. Did you get to it from under the truck? Was this wire some sort of ground wire? Did you replace it or just clean and reinstall?
 

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Discussion Starter #5
Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

Hey Guys,

Thanks for the feedback.
I will return to the wiring and see if I have missed something. Will let you know.

J
 

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Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

check all of the + - connections, spray them with Deoxit.
NOTE pay attention to the Postive disconnect junction at the battery,
if this part comes loose then a poor connection will be the result,
see if you can push the wire back into the terminal of if the wire is loose,
NOTE they do sell new + disconnect terminals
 

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since replacing this alternator I realize that it is not set up as traditional alternators are. I was told by my mechanic that it was pretty tricky getting to it to begin with. With that said will I have trouble mapping out the wiring schematics while I'm down there? Does anyone have a diagram of the exact wiring location on the 4.4 engine. Not a general diagram but a more precise diagram that will assist me in finding this gremlin. To think I replace this alternator for no reason makes me a bit sick to my stomach.
 

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Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

Other than the ETM in RAVE?
 

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Discussion Starter #10
Re: 2003 4.4v8 on 3rd Water cooled Alternator in a matter of days.

Alt No.3
I'm at 14.2 when cold with no load. Lights and heater she stays around 14v.
Once hot, it seems to drop a volt or so under load but still 14.2 when no load.

Alternator No.4 next I think.
 
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