Any help is appreciated with these two questions!

1. Does anyone know what the maximum current or power output of a 96'XJR alternator should be?

I suspect that my alternator might be a problem when it is under heavy loads (when car is slowing down and downshifting from 2nd to 1st or neutral, and when I am turning at low speeds - battery indicator goes way down and car stalls). Here is the video of me driving a few meters:

However, every guide on the internet on how to check the alternator always shows me the charging battery test; and I suspect that is how my mechanic checked it.

2. Is there a question I can ask my mechanic to make sure that he did what I wanted? (i.e. asking him if he "checked" the alternator results in "yes, it is charging ok").

 

OK,

I see a couple of things that worry me a tad.

The revs are dropping when you are doing whatever it is you are doing, that indicates the "idle control vale" is NOT keeping up with fluctuations, may only want a good clean and reset???.

The idle dropping so far will obviously "slow" the alternator significantly, and that may be enough to cause it to "de-excite", and hence stop charging, NOT common, but it is the brain for some reason.

The battery MAY be dying. These are a "juice hungry" car, and a battery that is 85% just will not cut it when the LOAD goes on.

My books and stuff state a 115amp Hitachi alternator. NOT offering any variation for the "R" spec??.

Testing at the battery is usually the way, and a good DVM will pick up errors. I usually get a stable reading, NO load, then gradually switch things on and ensure the reading does NOT drop below about 13.4V at 1200RPM.

Bad earth wire/s will reek havoc, much discussion about that in the archives.

HOWEVER, I still think your rapid and huge idle drop is doing nothing any favours.

My 3.2 sits at 13.2v at 700RPM, in D and a/c on, headlights on, stop lights on, stable as they come.

 

Thanks,
Yes, my mechanic did not properly reconnect the ground (I'll search forums for a good ref to this). But even before it would exhibit the same symptoms.

What I am doing is replacing my Idle Air Control Sensor, Throttle position sensor, and Crankshaft Position Sensor.

Is idle control valve an entirely different thing?

 

I think we are talking of the same item.

Different markets/countries have different names, and we are apparently the oddest???.

The ICV is on the throttle body, top rear. I have attched a parts drawing that may assist.



Item #15, Jaguar call it a "stepper motor", we call it an "idle control valve".

 

I personally think that the ICV is fine as his car does not have a high idle problem it has a low idle problem, idle drops low and it corrects itself at times and other times it just cant compensate and it dies. My belief is that it is the crankshaft position sensor that is failing sending on again off again readings. I once forgot to plug in my ICV after a throttle body cleaning and it did not cause the problem that is described above. And there is nothing wrong with the alternator as when he steps on the gas the voltage increases and lights get brighter, this is all normal. my 2 cents.