GS550e "interesting" ignition problem - dies when coils are hot

[Gorminrider]

apart from the obvious "spark disappearing" , It's the CHANGE of voltage drop when not functioning that would confirm electrical fault... and isolating the failed component is the game..There's a kill switch and fuse on the ignition circuit too.
There've been lots of threads agonizing over coils and black box when it was the kill switch at fault. AND when your brain needs a rest, it's a relief to switch focus to something simple and confirm they're not involved....gives the juices time to ferment 'a better idea"

as to reaching the coil's nogo spark voltage....If the the coils are good, they will spark at less than 12v* You could pull the light's fuse and that will tell you if a fault there is killing the bike Likewise, brake and turn signals fuses. Or if there's only one fuse, disconnect the headlamp-that's an extra 55watts available...that should test your theory.


*coil spark voltage-Mine do quite well when the starter is drawing the battery down to 11 and Greg T has knowledge of just how low they'll go!

Ok, I'd suspect that the Dyna is voltage sensitive - where points aren't. From experience with them on race bikes using total loss battery power, we've run as low as 9.9V measured post race. But restarting at that level wasn't even tried. A fresh battery might just solve all your problems.
Raises the question as to why the PO retrofitted points doesn't it.....

Never a bad idea to go back to the start of the trail before you get lost! I've been assuming all else is good with a working charging system, a half decent battery but if there's a possibiltiy something else is effecting the bike's electrical background, it's just as well to be sure there isn't.

[pdqford]

My head hurts wouldnt you have to make sure the crank position is with the points/dyna 'closed' on dwell so there is a permanent ground?

Exactly! You MUST have current flowing through the component (the coil in this case) to measure voltage drop in that component.

Another example, that connector you replaced in the coil circuit. You could have connected your meter probes to either side of that connector, energized the circuit so current is flowing through the connector, and your meter would measure ONLY the voltage that couldn’t get through the connector (i.e. the voltage dropped by the connector), as the rest of the available voltage IS flowing through the connector.

Say you had done this while the old connector was still on the bike and your meter read, say 0.9V.
Then you cleaned up/refurbished the connector and again measured the voltage drop across the connector and your meter read, say 0.4V.
I’d say you didn’t do a very good job cleaning up the connector. ;-)
A connector on a circuit that is only drawing 2 to 3 amps shouldn’t drop more that 0.1 to 0.2 volts.

Now my head is starting to hurt ..........

[ajh]

Damn! Still have the problem. Went for a test ride and it was much better....for almost 40 mins before it died. The coil connectors were definately troublesome but not the whole story. Waited 15 mins and it started right up again. I kept it going to get home by keeping revs above about 2,000rpm. After about 10-15 minutes cooling off it will always start again on the button and Its possible to keep it running at higher revs

So Im back to square one, will start testing again at the weekend

[ajh]

Done some voltage drop testing today across the loom. Got the following drops -
Battery to main fuse .3V (I think the main red wire in the fuse box seems to be the culprit so not easy to change without a new fuseholder)
Main fuse to switch .2v
Switch to igntion fuse .2v
Ignition fuse to coils .8v (kill switch has been bypassed by PO. And there is an extra orange/white wire in the switch loom but no terminal at the connector, anyone familiar with this? 11 wires in the loom, only 10 connectors.

So im losing about 1.5 volts in total at the coils
Measuring voltage across coil LT terminals I get above 9 volts

Something is heating up and failing because it starts and runs perfectly after about a 15 minute break following it dying. Im going to check voltage drops tomorrow whilst its running just to see if anything increases but Im pretty sure nothing does.

Interestingly I found a thread where someone has had exactly the same symptons and solved it by changing the coils - https://www.reddit.com/r/Fixxit/comm...ve_this_bikes/

[pdqford]

Done some voltage drop testing today across the loom. Got the following drops -
Battery to main fuse .3V (I think the main red wire in the fuse box seems to be the culprit so not easy to change without a new fuseholder)
Main fuse to switch .2v
Switch to igntion fuse .2v
Ignition fuse to coils .8v (kill switch has been bypassed by PO. And there is an extra orange/white wire in the switch loom but no terminal at the connector, anyone familiar with this? 11 wires in the loom, only 10 connectors.

So im losing about 1.5 volts in total at the coils
Measuring voltage across coil LT terminals I get above 9 volts

By Jove, I believe you are digging where the ‘tatters are!

Just a few comments:

What is the voltage drop across the Just the main fuse?
(I see where you dropped 0.3V from battery TO the main fuse, and dropped 0.2V FROM main fuse to switch. But how much voltage was dropped ACROSS the just main fuse itself? Some fuses, especially glass ones, can cause significant drops.)

Ditto for the drop ACROSS the switch, the ignition fuse. Just cleaning up those connection points with Deoxit will pick up some voltage.

I’m drawing a blank as far as the term “LT” means, but if you are dropping 9 volts across just the coil primary, that coil is open. In other words, 9 volts is flowing through your meter and barely any voltage is flowing through the coil primary. (Remember, when checking voltage drops, your meter is in parallel with the component being checked, so the meter reads out the voltage that can’t get through the component (coil) being checked.)

And as always, it is difficult for me to see just where your meter probes are connected, and it is just as difficult for me to describe where they need to be connected.

[Gorminrider]

again, I'll ask: Do you see spark when bike quits working? and Did you test coils voltage drop when cold/working versus hot/not working?

Ignition fuse to coils .8v (kill switch has been bypassed by PO. And there is an extra orange/white wire in the switch loom but no terminal at the connector, anyone familiar with this? 11 wires in the loom, only 10 connectors

This forum is familiar with the archetypal Previous Owners particularly the Kill switch disabled suggests the ignition failed THERE before OR the PO couldn't figure out how to arm/disarm the coils with the relay in place. That's not a good sign.

Quite possible coils are thrashed but the general idea of troubleshooting is to be as sure as you can be that A) they are the problem B) and that replacing them won't just destroy them again due to the reason the first ones failed. It may be the PO destroyed coils experimenting but managed to undo what killed coils such that they were able to sell it to you with bad coils.

But you want to be as sure as you can before buying pricey components.

An aside per .2v drop on just wires end to end : Motorcycles of this ilk tend to use thin wire to keep the harnesses compact and flexible red->key ->orange->to fuseblock is a long loop carrying all current used... likewise ignition Orange/whitestripe or Lights Or/redstripe from the fusebox. so they can have tiny voltage drops carrying sizeable current. (.2v=1.6% of 12.5v ideally should be 0 but acceptable)

Ignition fuse to coils .8v

that's a lot, but does it include the relay...which I assume is still in play? it's little coil I assume is permanently "on" tapped into the ignition circuit and part of the sum. I'd get rid of it for simplicity's sake and it may even be part of the problem

[ajh]

thanks guys, really appreciate you taking the time. Hopefully all this detail might help someone else too.

pdqford - im not familiar with trying to test the drop across the coil low tension (LT) positive to negative terminals but I thought I did what you said in previous post. I put the meter across the 2 terminals and made sure the negative (the wire going to points/dynaS) was ground ie. as in when points would be closed. I get 9v because the meter is wired to ground and positive and measuring voltage, not voltage drop. What am i missing?

Gorminrider - stupid question but what relay are you referring to?

Today I checked the voltage drop in total to the coils whilts running and it stayed below 1.5v. I have 12-13V at the coils whilst running so I think its enough. I also wired up the strobe light as i can now run the bike until it fails on idle and watch the strobe. I can see the spark faltering badly on number 2 and number 4 lead as it gets close to dying. I could always hear it but this now shows the spark dropping out. I can also feel the coils getting hot around the terminal ends. So Im now pretty sure both coils are failing when they get hot. When they've cooled the bike runs and idles as sweet as possible

Can you guys recommend a make of coil to buy? Im finding it hard to justify Dynas as its a standard tune engine and they are 4 times the price of regular aftermarket coils.
Any thoughts on resistance? I was thinking the 3ohm would offer a better spark but the 5ohm might run cooler

[ajh]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?) As i said on my loom I only have one O/W terminating at the plug but there are 2 in the loom and the diagram shows them as both sides of the switch which makes sense. However, the PO has joined one of the O/W wires to the O wire which looks like its the feed for the lights! I need to try to work out wtf this PO has done as this is definately dropping more than half a volt - Now my head is hurting again!

IMG_4750.jpg

oohps! wrong wiring diagram see later posts!

[pdqford]

thanks guys, really appreciate you taking the time. Hopefully all this detail might help someone else too.

pdqford - im not familiar with trying to test the drop across the coil low tension (LT) positive to negative terminals but I thought I did what you said in previous post. I put the meter across the 2 terminals and made sure the negative (the wire going to points/dynaS) was ground ie. as in when points would be closed. I get 9v because the meter is wired to ground and positive and measuring voltage, not voltage drop. What am i missing?

ajh, your not missing a thing! As I understand it you have your meter hooked up correctly to check voltage drop across the coil.
Thanks for explaining the “LT” to me. I’m used to calling it the “primary side” of the coil.

With your meter hooked up to the positive and negative sides of the coil, your meter provides a “parallel” circuit with the coil primary. When you pass current through the circuit most of the voltage passes through the coil, and any coil resistance restricts some of the voltage from going through the coil. That voltage finds its way through the “parallel” circuit, which is in fact, YOUR meter. So your meter displays the voltage that is not being used by the coil, and is the voltage DROPPED by the coil.

In a perfect world all the voltage would go through the coil primary and your meter would show 0.0V being dropped by the coil. But since your meter shows 9.0V being dropped by the coil, there is very little voltage going through the coil. That is why I posted earlier that your coil primary is nearly “open”, as in it doesn’t have a path for the voltage to follow. It is possible for an ohm meter to find a path through the coil if there is just a single strand of wire making contact through the coil because the ohm meter puts out a very minimal amount of current when it tests a circuit. Heck, it can’t even get the coil warm.

But put your bikes full battery current through the coil primary and if there is a week spot in the coil primary it will heat it up and cause some real resistance, which will be measured via voltage drop testing.

Now I have to go rest.

[Gorminrider]

right. No relay? I must have mixed you up with another thread, sorry.

Anyways, you've established it's ignition failure. Probably a cooked coil -age alone can kill some of them.
but I'm still a little unsure what burned it out....hoping it's not the doofunny black box that controls the coil...Your coils are meant to work in concert with the device that is pulsing them..and, it's not the primary alone that makes the spark. It's the combination of primary and secondary- a coil is a transformer. You would want to not burn out whatever is pulsing the coils either.

here's a diagram per voltage drops on a headlamp from
http://www.genebitsystems.com/david/...ical/index.htm
you might want to read this too
http://www.genebitsystems.com/david/...onProblems.htm


voltage drop.jpg

this method is an example with the negative probe fixed on the negative pole of the battery 16 and as it moves along, it is summing the "voltage drops" towards the positive pole.1..until across the battery poles (16-.1)you get the battery's voltage which =the circuits sum voltage=12.2.... you'll see that the meter would display (12.088-0.121=) 11.967v across just the light (13-..12) The meter has a very high resistance and doesn't have much effect on the circuit as a parallel load which is why and where it is really handy.

[Gorminrider]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?) As i said on my loom I only have one O/W terminating at the plug but there are 2 in the loom and the diagram shows them as both sides of the switch which makes sense. However, the PO has joined one of the O/W wires to the O wire which looks like its the feed for the lights! I need to try to work out wtf this PO has done as this is definately dropping more than half a volt - Now my head is hurting again!

On these Suzukis, O alone runs from the key to fusebox, feeding the fusebox where after O/W is ignition and, O/R is headlight and dashlamps...memory Y/G is the starter button to solenoid, but possible detour through a clutch switch...
but a PO could certainly do it differently.

[ajh]

On these Suzukis, O alone runs from the key to fusebox, feeding the fusebox where after O/W is ignition and, O/R is headlight and dashlamps...memory Y/G is the starter button to solenoid, but possible detour through a clutch switch...
but a PO could certainly do it differently.

So I now have another wiring diagram and it looks like the PO has used a UK 1981 550L right handlebar switch with 2 O/W wires and grafted a different connector plug on to fit my UK 1982 550E loom. Its a tidy job on the connector as it looks stock which doesnt match his other work! More investigation needed to understand WTF has been done!

Thanks Gorminrider!

[pdqford]

Regarding this extra wire, I had a look at the wiring diagram and it shows the 2nd O/W wire but it then "joins" it to Y/G (is this a relay or something?);

No, that is not a relay. It is the starter button.
Current comes up that left most O/W wire on your attached diagram and goes to the “E” switch in your attached diagram. That is the E-ngine kill switch. If the E switch is closed, current continues on through the E switch and gets split into two circuits at that splice in your diagram. The current continues on one circuit via the O/W wire to power the ignition system, and also continues on the 2nd circuit to the starter button. When the starter button is pressed current goes through the starter button and on out the Y/G wire to power the starter circuit.

[ajh]

Now I have the correct wiring diagram! Still have this mystery of an extra O/W wire in the switch loom connected into the handlebar switch which I suspect is powering the starter button. But it does not exit the loom! Weirdest thing I've seen as the loom 'looks' unmodified apart from the join of O & O/W. Want to avoid cutting up the switch loom outer covering, by default would there be a splice in the loom to the other O/W?
In the diagram I've edited to show my wiring - Weird but it works!

IMG_4755.jpg

[Gorminrider]

That IS peculiar^^kill switch dectivated and the starter button (that activates solenoid) doesn't appear to have power from your diagram unless your orangish swipe mark is an existing wire the PO did? if so, it'll work but no kill switch.*

That line at the top of the switch is an Still have this mystery of an extra O/W wire in the switch loom connected into the handlebar switch which I suspect is powering the starter button. But it does not exit the loom!

Yes that would be the line drawn at the top between and connecting the two switches.They didn't indicate its colour on the diagram. It does not exit the loom. It goes from Kill switch to starter button . In this way, the starter button is part of the "ignition circuit' O/White stripe wire indicates ignition circuit until they used differing colours like the Y/G for solenoid branching off.

It can get confusing, but if you think of any wire mainly Orange wires as being arteries and the others being capillaries it might help..I guess Red has to be seen as "the heart"? Without medical knowledge my analogy is not going to be great but you get what I mean...

*kill switch" mystery. Plainly the PO considered it a problem. it's easiest to think it's just a faulty switch that was not considered to be necessary. Many riders never think of it except when it gets flicked by accident! Not fatal to ignition and probably not the problem unless somehow other circuits were affected by its intermittent failure?