KAD32 no RPM and no ignition light. Volt meter only showing 12v when running.

[Kengillies]

Hi

VovloPenta KAD32, no reading on rev counter (there is power going to it as it moves slightly when ignition turned on). When engine starts the dial on rev counter remains at zero. Also no ignition light when ignition is turned on.

If I press the test button all lights illuminate including ignition.

Engine starts and runs fine supercharger kicks in fine. Voltmeter sits at 12v when running. Should probably sit at 13.5 or above.

I am thinking the alternator has failed, as the W wire at rear of alternator supply’s the Rev gauge.


However I am not sure regarding no ignition light. I didn’t have any tools or multi meter with me yesterday so will check it out at the weekend.

Looking for any advice or suggestions to look out for or check for if it’s something obvious.

I am aware the volt meter should be more than 12v when running and the 12v from the ignition light to the D+ on the alternator is also the exciter for the alternator (I think)

Any ideas welcome or any advice on wiring setup from engine / alternator / rev counter would be good. I would like to understand the wiring from Rev Counter and ignition to the alternator.

I will put meter on alternator and check output.

Thanks in advance

Kenny

 

[volvopaul]

Failed alternator but check you have 12volts at the yellow sensing cable no , 12volt no excitement at yellow wire , does system have a split charge ?

 

[Kengillies]

No split charge, I also think it’s the alternator. I will install a new one at the weekend and check all wiring before hand. It was the no ignition light I was struggling to understand.
It was my understanding when you turn on ignition the light comes on and 12volts would go to the alternator when engine starts then an equal current/charge comes from alternator so light goes out.

So why now is ignition light not coming on to show alternator not charging?

Thanks again for your reply

 

[Momac]

If the alternator is corroded does this possibly indicate a leak from the water pump.

 

[Kengillies]

Yes, replaced the raw water pump last year was in the Clyde (sea water) obviously never washed salt of enough. Now in Loch Lomond.

Tomorrow I will run wire from negative onto the exciter connection and hopefully should see ignition light come on when ignition is on. New alternator arrived earlier

 

[stone beach]

The clue is in the light not coming on at switch on

It was my understanding when you turn on ignition the light comes on and 12volts would go to the alternator when engine starts then an equal current/charge comes from alternator so light goes out.

You are mostly correct, bold text is incorrect, delete it.

So, if the light isnt coming on and the bulb is OK the exciter wire isn't connected, therefore no excitation, so no output. Trace that wire back, comes from your key switch.

 

[stone beach]

The bulb is first thing to check

 

[Kengillies]

The clue is in the light not coming on at switch on

It was my understanding when you turn on ignition the light comes on and 12volts would go to the alternator when engine starts then an equal current/charge comes from alternator so light goes out.

You are mostly correct, bold text is incorrect, delete it.

So, if the light isnt coming on and the bulb is OK the exciter wire isn't connected, therefore no excitation, so no output. Trace that wire back, comes from your key switch.

Hi
Thanks for that, I will check it over the weekend. I think if I take a negative and touch it to the exciter (ignition on engine off) then check if bulb illuminates. This will proof the circuit from ignition to bulb to alternator.

If still no light I will trace the wire back.

If I get a light I will swap alternator