ignition switch mystery

[YamYam]

Has anyone come across this before? Starter battery fine and starts the engine first time. However when I switch the ignition on I have time for a coffee and a ciggie before before the ignition lights come on and I'm ready to go. Can live with it but seems a very weird thing to be happening. Bit of a pain though so was wondering if the experts among you have any clues. Thanks in advance

[nicknorman]

Presumably just a bad connection somewhere. What is probably happening is that a small current is flowing through the bad connection. The resistance of the bad connection means that there is not enough current to light the bulbs etc, but heat is generated. As the bad connection warms up, things expand / dry out and it starts working. Try wiggling the key switch and poking about with the connections on the back of the panel and engine harness. Depending on your engine make, some have a fuse in the wiring loom near the engine which can corrode. Usually there will also be a multiway connector somewhere near the engine which can also suffer from corrosion.

[YamYam]

Presumably just a bad connection somewhere. What is probably happening is that a small current is flowing through the bad connection. The resistance of the bad connection means that there is not enough current to light the bulbs etc, but heat is generated. As the bad connection warms up, things expand / dry out and it starts working. Try wiggling the key switch and poking about with the connections on the back of the panel and engine harness. Depending on your engine make, some have a fuse in the wiring loom near the engine which can corrode. Usually there will also be a multiway connector somewhere near the engine which can also suffer from corrosion.

thanks nichnorman, the ignition light does faintly glow occasionally before full sometimes and the rpm needle flickers. Not that up on electrics and theres the usual spaghetti of wiring in there which has slightly put me off messing in there

[nicknorman]

Ok well you could try to locate the multiway connector and fuse - if you have them. What model of engine?

[YamYam]

Its a marinised Mitsubishi 4 pot (apologies to vintage engine lovers. Can hear the tutting from here :-) ). As I say im a complete durr brain when it comes to 12v electrics so please have a good laugh at my expense at my next statement but if I don't sort it is there any chance of further damage to the loom or even fire perhaps. Now you can laugh :-)

[Tony Brooks]

If its a Vetus marinisation some early ones had a circuit breaker mounted at the back of the rocker cover. and that could be the source of the apparent poor connection. With age the ignition switches can also go resistive but I agree. First check for multi-plug in the main engine harness, then for a fuse, probably a hidden in-line one. Then all connections behind the instrument panel and on the master switch.

 

Just to be sure, you are not looking at some kind of glow plug warning lamp?

[nicknorman]

Its a marinised Mitsubishi 4 pot (apologies to vintage engine lovers. Can hear the tutting from here :-) ). As I say im a complete durr brain when it comes to 12v electrics so please have a good laugh at my expense at my next statement but if I don't sort it is there any chance of further damage to the loom or even fire perhaps. Now you can laugh :-)

Presumably this question is based around "can I just do nothing and live with it?" To which the answer is yes and no! Where there is corrosion there is already damage, so a bit of arcing and localised overheating is unlikely to make it much worse. Most of the current flows prior to engine start, once it is running there is less, so it's unlikely to cause a fire.

 

However it is also unlikely to get better on its own, and one day soon the lights may never come on when you try to start, so probably the alternator wouldn't work. Whether this is an issue for you depends on your usage pattern. Also bear in mind that the bad connection might recur whilst the engine is running. This wouldn't stop the engine (unless you have an energise to run stop solenoid which I doubt - the clue would be that the normal method of stopping the engine is just to turn off the key switch) but it might mean that the warning lights and buzzer no longer worked so if, say, the alternator belt broke (which probably also drives the water pump) you wouldn't know about it until the engine boiled or seized and/ or batteries were flat.

 

I would get it fixed sooner rather than later.

Edited April 28, 2014 by nicknorman

[YamYam]

If its a Vetus marinisation some early ones had a circuit breaker mounted at the back of the rocker cover. and that could be the source of the apparent poor connection. With age the ignition switches can also go resistive but I agree. First check for multi-plug in the main engine harness, then for a fuse, probably a hidden in-line one. Then all connections behind the instrument panel and on the master switch.

 

Just to be sure, you are not looking at some kind of glow plug warning lamp?

Thanks for input Tony, looks like a good rummage around tomorrow. No, don't have a glow warning lamp, just have to hold the key in a certain position for 10 to 15 seconds. This is the red ignition and alternator light that as I say take several minutes to come on when turning on the ignition

Presumably this question is based around "can I just do nothing and live with it?" To which the answer is yes and no! Where there is corrosion there is already damage, so a bit of arcing and localised overheating is unlikely to make it much worse. Most of the current flows prior to engine start, once it is running there is less, so it's unlikely to cause a fire.

However it is also unlikely to get better on its own, and one day soon the lights may never come on when you try to start, so probably the alternator wouldn't work. Whether this is an issue for you depends on your usage pattern. Also bear in mind that the bad connection might recur whilst the engine is running. This wouldn't stop the engine (unless you have an energise to run stop solenoid which I doubt - the clue would be that the normal method of stopping the engine is just to turn off the key switch) but it might mean that the warning lights and buzzer no longer worked so if, say, the alternator belt broke (which probably also drives the water pump) you wouldn't know about it until the engine boiled or seized and/ or batteries were flat.

I would get it fixed sooner rather than later.

Thanks nicknorman, stating the obvious really. I suppose i knew that all along, just needed the confirmation. One more job on the ever growing list :-). Thanks again for taking the time to give a really succinct reply

[kevinl]

Has anyone come across this before? Starter battery fine and starts the engine first time. However when I switch the ignition on I have time for a coffee and a ciggie before before the ignition lights come on and I'm ready to go. Can live with it but seems a very weird thing to be happening. Bit of a pain though so was wondering if the experts among you have any clues. Thanks in advance

I'm not with this, I don't have and can't recall seeing an ignition light on any boat I've ever been on and why do you have to wait for it to come on before you move off? All the lights on mine come on when the ignition is turned on then go off when the engine starts and the oil pressure, alternator and what have you kick in, what's this light tell you? New one on me is it engine temp too low or something like that or is it just something I've never come across before.

K

[Iain_S]

I'm not with this, I don't have and can't recall seeing an ignition light on any boat I've ever been on and why do you have to wait for it to come on before you move off? (Snip)

Also known as Generator Warning Light, Alternator light, etc., etc.

 

Iain

[Tony Brooks]

I'm not with this, I don't have and can't recall seeing an ignition light on any boat I've ever been on and why do you have to wait for it to come on before you move off? All the lights on mine come on when the ignition is turned on then go off when the engine starts and the oil pressure, alternator and what have you kick in, what's this light tell you? New one on me is it engine temp too low or something like that or is it just something I've never come across before.

K

 

Because there is probably a fault in his wiring, switch or relay somewhere. That's why he is asking. Yes the warning lamp most of us call the ignition warning lamp as a sort of shorthand is indeed a lack of charge warning lamp but it could also be a low oil pressure warning lamp. Temperature warning lamps normally stay off until an overheat and then fail to come on because a bulb has blown or there is corrosion. That's why its a good idea to "earth" the temperature warning lamp transmitter wire now and again to ensure it comes on.

 

I think I have seen glow plug warning lamps that come on when it is time to operate the starter which is why I mentioned it but most go out.

[YamYam]

I'm not with this, I don't have and can't recall seeing an ignition light on any boat I've ever been on and why do you have to wait for it to come on before you move off? All the lights on mine come on when the ignition is turned on then go off when the engine starts and the oil pressure, alternator and what have you kick in, what's this light tell you? New one on me is it engine temp too low or something like that or is it just something I've never come across before.

K

 

Thats my problem kevinl. Perhaps didnt explain it that well but when I first put the key in and turn it absolutely nothing happens. But turn it into the ignition position have to wait a few minutes before it suddenly all lights up then I can warm the plugs and then start the engine

Also known as Generator Warning Light, Alternator light, etc., etc.

 

Iain

Yes, thanks Iain. Sorry for any confusion but always called it the ignition switch. Bit like a car I suppose. Turn it on, red lights come on, start the car and everything goes off hopefully :-)

[kevinl]

Mine (a Vetus so Mitsubishi too) it did something like that, press the engine start button and nothing, go inside turn a light on, fill the kettle so the water pump came on, put the radio on then the engine would start. It turned out the isolator switch was on it's way out and some how using a few low load things perked it up enough to convince the engine to work. I was going to post on here asking why I burn an isolator switch out every 18 months does the Mitsubishi take a heavier that normal start load possibly? I'm about to put my 4th one in soon, can't be right. You could try shorting across the back of the isolator switch with a screwdriver see if that does it, costs nothing and eliminates it from list of possibilities other than that you're probably looking for a loose wire or connector as has been said, have a poke around while someone watches the lights.

K

[YamYam]

Mine (a Vetus so Mitsubishi too) it did something like that, press the engine start button and nothing, go inside turn a light on, fill the kettle so the water pump came on, put the radio on then the engine would start. It turned out the isolator switch was on it's way out and some how using a few low load things perked it up enough to convince the engine to work. I was going to post on here asking why I burn an isolator switch out every 18 months does the Mitsubishi take a heavier that normal start load possibly? I'm about to put my 4th one in soon, can't be right. You could try shorting across the back of the isolator switch with a screwdriver see if that does it, costs nothing and eliminates it from list of possibilities other than that you're probably looking for a loose wire or connector as has been said, have a poke around while someone watches the lights.

K

Thanks Kevinl, thats not a bad idea. Strange thing is with mine as well is if I put the battery charger on my start battery and switch it on the ignition light comes on straight away even though the batteries fully charged although just lately thats been a bit hit and miss. Think everythings pretty original on mine which is now 24 years old so I shoukd be pleased its all lasted this long without many major dramas :-)

[bottle]

Mine (a Vetus so Mitsubishi too) it did something like that, press the engine start button and nothing, go inside turn a light on, fill the kettle so the water pump came on, put the radio on then the engine would start. It turned out the isolator switch was on it's way out and some how using a few low load things perked it up enough to convince the engine to work. I was going to post on here asking why I burn an isolator switch out every 18 months does the Mitsubishi take a heavier that normal start load possibly? I'm about to put my 4th one in soon, can't be right. You could try shorting across the back of the isolator switch with a screwdriver see if that does it, costs nothing and eliminates it from list of possibilities other than that you're probably looking for a loose wire or connector as has been said, have a poke around while someone watches the lights.

K

 

 

Why, probaly because you are putting to much load through.

 

Put a larger one (amps) in and make it a decent one.

[Scholar Gypsy]

Thanks to all - this thread is v helpful to me.

 

I had a similar issue last week (Mitsubishi K4E engine), where the heaters worked and the engine started fine, but the water and oil guage did not move, and neither did the alternator kick in. A gentle bash to the panel did the trick, but I need to track down the loose connection before someone gets stranded....

[Titan]

I would check if a starter circuit should actually be run through an isolater at all ??? Thats why they have solenoids ??? i havent checked bss but iirc the starter is a direct feed from battery ? This is perhaps why the isolater is burning out ???

I would check if a starter circuit should actually be run through an isolater at all ??? Thats why they have solenoids ??? i havent checked bss but iirc the starter is a direct feed from battery ? This is perhaps why the isolater is burning out ???

[Scholar Gypsy]

I would check if a starter circuit should actually be run through an isolater at all ??? Thats why they have solenoids ??? i havent checked bss but iirc the starter is a direct feed from battery ? This is perhaps why the isolater is burning out ???

 

The starter on my boat is connected via the isolator (neg side), and both have lasted for 20 years (nearly).

[kevinl]

I would check if a starter circuit should actually be run through an isolater at all ??? Thats why they have solenoids ??? i havent checked bss but iirc the starter is a direct feed from battery ? This is perhaps why the isolater is burning out ???

How can you earth the starter motor alone, is that possible?

K

[Scholar Gypsy]

How can you earth the starter motor alone, is that possible?

K

One could have one isolator for the starter (and other related engine stuff eg heaters, starter solenoid, alternator circuit), and another for the domestic supply circuits, but I am not quite sure what the advantage would be.

[kevinl]

One could have one isolator for the starter (and other related engine stuff eg heaters, starter solenoid, alternator circuit), and another for the domestic supply circuits, but I am not quite sure what the advantage would be.

But, but, how The whole system earths via the hull so one isolator switch would bypass the other unless you physical insulated every component starting with the engine wouldn't you?

[Scholar Gypsy]

Ah, on my boat the starter neg cable does go back to the battery, rather than via the chassis/hull. I should have said that if you are going to have two isolators rather than one then you can put them on the pos side of the battery.

[Alan Saunders]

I think the confusion factor here is that, whilst it may be possible to have an isolated return (negative) to a starter motor, the vast majority have the return connected to their casing which is firmly bolted to the engine.

 

If the isolator is fitted immedately after the positive or negative terminal of the starter battery it will conduct the full starter current.

My common, cheap (~£5) isolator has needed occasional maintenance/cleaning over the past 27 years.

v v v Pic below! v v v

Getting back to the OP's problem :

We all start by checking the battery voltage at the source, the battery terminals, not the lugs (12.6V good)! Then the voltage at the sink (destination).

With power on, if there is a considerable difference we need to find where the loss occurs, now - this is not the time to have a fag or a coffee!

 

Halve the problem, set your DVM to the 2V range and measure the difference between positive source and sink then the negative source and sink.

Chase the greatest loss. Measure voltage drop at intermediate terminals. If you cannot pierce a connection, leave the meter connected either side and reseat, stress that connector/leads and note any change.

 

When you have fixed the major loss (e.g.positive circuit) go back and check the other circuit.

 

No harm in cleaning, tightening all the connectors between the battery and the panel but measuring voltage drop will tell you where the problem is and save some effort.

 

e.g. My 1987 Vetus panel had a circuit board with several relays and diodes that operate the various warning sytems; low oil pressure, high water or exhaust temperature etc. Occasionally, with the engine running, the rev-counter would drop to zero. Momentarily hitting 'start' (or stop) would restore normal operation. Poor connections in the several nine-way AMP connectors were the cause of the problem.

 

BTW, Are you certain that you cannot start your engine when there are no indicator lights on? Some control panels will stop the engine if there is a fault but this is undesirable on a boat and can usually be disabled. If you have a simple panel with no interlocks chances are that pre-heaters and starter (not battery charging) may work with no indicator lights.

 

HTH, Alan

[Tony Brooks]

One could have one isolator for the starter (and other related engine stuff eg heaters, starter solenoid, alternator circuit), and another for the domestic supply circuits, but I am not quite sure what the advantage would be.

 

The advantage is that they would be in the positive cables not the negative. This means there is no chance of doing rather a lot of damage to certain electrical equipment if something is turned on with a single negative isolator turned off. Gibbo explained it years ago when he said that one should always disconnect the positive battery terminals first. Not a bright idea on a typical modern narrowboat (spanners too close to steel) so I say turn EVERYTHING off, turn off the isolators, then disconnect the negatives.

 

It si generally accepted as not best practise to put master switches in the negative nut if its a simple boat it will normally be OK.

[YamYam]

I think the confusion factor here is that, whilst it may be possible to have an isolated return (negative) to a starter motor, the vast majority have the return connected to their casing which is firmly bolted to the engine.

 

If the isolator is fitted immedately after the positive or negative terminal of the starter battery it will conduct the full starter current.

My common, cheap (~£5) isolator has needed occasional maintenance/cleaning over the past 27 years.

v v v Pic below! v v v

Getting back to the OP's problem :

We all start by checking the battery voltage at the source, the battery terminals, not the lugs (12.6V good)! Then the voltage at the sink (destination).

With power on, if there is a considerable difference we need to find where the loss occurs, now - this is not the time to have a fag or a coffee!

 

Hi Alan. Many thanks for your input. No, the engine definitely won't start without the ignition lights on but I'm currently cleaning all the wiring connections at the moment.. Very slowly I might add as don't want to end up with several wires adrift and have no idea wnere they go back to. However the isolater switch may prompt further investigation as I know thats not been touched or cleaned in several years. Being a cheapskate I usually borrow my neighbours voltmeter but he's away till wednesday so if my cleaning doesn't work I will try your other suggestion. Thanks again. Rob

 

Halve the problem, set your DVM to the 2V range and measure the difference between positive source and sink then the negative source and sink.

Chase the greatest loss. Measure voltage drop at intermediate terminals. If you cannot pierce a connection, leave the meter connected either side and reseat, stress that connector/leads and note any change.

 

When you have fixed the major loss (e.g.positive circuit) go back and check the other circuit.

 

No harm in cleaning, tightening all the connectors between the battery and the panel but measuring voltage drop will tell you where the problem is and save some effort.

 

e.g. My 1987 Vetus panel had a circuit board with several relays and diodes that operate the various warning sytems; low oil pressure, high water or exhaust temperature etc. Occasionally, with the engine running, the rev-counter would drop to zero. Momentarily hitting 'start' (or stop) would restore normal operation. Poor connections in the several nine-way AMP connectors were the cause of the problem.

 

BTW, Are you certain that you cannot start your engine when there are no indicator lights on? Some control panels will stop the engine if there is a fault but this is undesirable on a boat and can usually be disabled. If you have a simple panel with no interlocks chances are that pre-heaters and starter (not battery charging) may work with no indicator lights.

 

HTH, Alan