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Isuzu control panel acting weird


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We have an Isuzu control panel for our boat. Yesterday it started to make little random chirping sounds like a bird, and the engine hours display was flashing. Today the engine hours are blank, but it's still chirping. If I put the key into the zero position, no more funny noise. Both batteries seem to be charging fine, and seem to be holding a charge.

 

Any ideas? Thanks

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The toy voltmeter indicates getting on for 15 volts so I suspect that you have solar charging. If so I suspect the two "faults" are unrelated. It will certainly do no harm to check the multi-plug,. Before you do that get the chirping and turn on a heavy electrical load. There is a fair chance the chirping will stop. I suspect the solar has pushed the battery voltage up so far the alternator controller is cycling on and off and for each off period the warning buzzer gives a little chirp. If I am right is annoying/worrying rather than an actual fault.

 

If you cup your hands around the charge warning lamp you might see t glowing slightly.

 

My guess re the hour display is that is the usual damp/corrosion problem and soon it will refuse to display at all.

 

 

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Thanks for your help everyone. No joy so far, but here's an update....

 

1. No solar on this boat - but thanks for the suggestion.

2. I managed to trace some wires using a multi-meter from the back of the control panel (I followed one from the actual engine meter display) - through the wiring loom, and through that big plug - to the end where it's connected to a sensor. I did this on a couple of wires, and they all were a complete circuit. 

3. I also powered everything up to see if the chirping would stop - it didn't, I also didn't see the light flicker.

 

Could it be a sensor? 

 

 

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I could well be the oil pressure switch/sensor. Pull the wire(s) off it, noting which  goes where and see if it stops. is most likely a sensor/switch fault.

 

Could also be an overheat sensor, same applies.

 

If there is a loose connection between battery and ignition switch than makes and breaks. That could make it chirp as the ignition switch looses the feed.

Edited by Tony Brooks
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Hi

Do you mean the alarm buzzer is making a noise? Mine sometimes does this when the engine is first engaged in gear and the oil hot. The oil pressure falls slightly before the engine picks up. It is too quick to flash the warning lamp. The hours meter is random on mine sometimes it works sometimes it does not. The buzzer is more sensitive than the warning lamps so it could be low oil pressure or alternator not charging at tickover.

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7 minutes ago, WotEver said:

It ain’t that if he’s getting 15V displaying. 

The alarm does not measure the battery voltage but has a diode 'OR' logic circuit to the warning lamp on the alternator. It does not matter what the battery voltage is if the alternator drops out from charging at low speed or any speed due to slipping belt or failing alternator it could cause this effect.

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20 minutes ago, Mike Adams said:

The alarm does not measure the battery voltage but has a diode 'OR' logic circuit to the warning lamp on the alternator. It does not matter what the battery voltage is if the alternator drops out from charging at low speed or any speed due to slipping belt or failing alternator it could cause this effect.

I repeat, if he’s seeing circa 15V then the alternator hasn’t ‘dropped out’. Quite the contrary. 
 

If that 15V is anything like accurate he’s also boiling his batteries. 

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If that boy racer voltmeter is accurate then maybe he has lost a field diode or two in the alternator. However I don't really see why the meter would chirp. I note the photo shows tickover so maybe the slight speed up on a power stroke is enough to stop the buzzer.

 

Remember the output of the field diodes and the main diodes are two different things. The lamp and buzzer in effect react to field diode output while the main diodes provide the battery charge.

 

As of yet the OP does not seem to have reported the results of disconnecting the oil and temperature switches/senders so we can't be sure what system is causing the chirping. I suspect it may well be the charging circuit but it could also be something making and breaking the feed to the ignition switch so when that feed is broken the ignition controlled equipment tries to be fed from the field diodes. At least that might explain the hour counter going on and off.

 

Questions: did the hour counter turning off in time with the chirp with it being off when the chirp sounded? Does it still do it at 1500 rpm? Please use your multimeter to confirm that 15V reading on the voltmeter and do you know which alternator/battery its monitoring.

 

At present I still suspect two faults but can't rule out a common cause.

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Te OP post shows the engine at tickover. You have no way of knowing if the alternator is actually charging at that point. When the engine speeds up it may charge and probably does depending on the circumstances (such as a slipping belt). Your only indication is the warning lamp and the buzzer that are the same thing except the buzzer responds more quickly than the lamp to rapid changes in voltage. The alternator will cut out when a certain voltage is reached but you have no way of knowing that from the indicator lamp and it will not light up to say it has stopped charging.

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Just now, Mike Adams said:

Te OP post shows the engine at tickover. You have no way of knowing if the alternator is actually charging at that point. When the engine speeds up it may charge and probably does depending on the circumstances (such as a slipping belt). Your only indication is the warning lamp and the buzzer that are the same thing except the buzzer responds more quickly than the lamp to rapid changes in voltage. The alternator will cut out when a certain voltage is reached but you have no way of knowing that from the indicator lamp and it will not light up to say it has stopped charging.

and if a field diode or oscillating voltage regulator is implicated the warning lamp glow is unlikely to be visible in daylight so it needs shielding so its in virtual darkness.

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3 hours ago, phantom_iv said:

Is it really reading 15V, or is that a parallax error and it's more like 14?

That is why I asked for conformation this morning.

 

We are also assuming its a charging problem but until we get the actual results of the tests on the temperature and oil pressure switches/senders we can't rule them out.

 

We also don't know if its the engine or domestic batteries connected to that voltmeter.

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14 hours ago, Mike Adams said:

Te OP post shows the engine at tickover. You have no way of knowing if the alternator is actually charging at that point.

Of course we do. Where do you suppose the 15V is coming from?


If indeed the 15V reading is accurate of course. 

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14 hours ago, Tony Brooks said:

If that boy racer voltmeter is accurate then maybe he has lost a field diode or two in the alternator. 

I wondered the same thing but like you I can’t see that it would have any relation to the chirping. 

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9 hours ago, WotEver said:

Of course we do. Where do you suppose the 15V is coming from?

Where does this 15v come from? There is a  voltmeter shown but as mentioned earlier you are not looking at it straight on so I recon it reads anywhere between 13.5 and 14. Anyway if it has two alternators which the panel suggests either one could trigger the alarm.

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43 minutes ago, Mike Adams said:

Where does this 15v come from? There is a  voltmeter shown but as mentioned earlier you are not looking at it straight on so I recon it reads anywhere between 13.5 and 14. Anyway if it has two alternators which the panel suggests either one could trigger the alarm.

That is why I asked the OP to confirm that reading yesterday morning and it seems he has yet to respond. Even apart from the possibility of parallax error I do not trust those voltmeters.

 

It will take many engine starts before the start battery shows signs of being discharged if it's not being charged so we really need to know what tests the OP has done to confirm both batteries are being charged. I suspect the engine one may not be. If this is related to a main diode failure (and I am far from saying it is) most people will say the batteries are being charged.

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