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S3 955i electrical issues, voltage drop, etc.

10K views 48 replies 4 participants last post by  Laczi 
#1 ·
I started "tripling" this year, with an imported bike (service history unknown), so problems slowly come to the surface.

My bike's first electrical symptom:
It's a 2002 model with light switch, so it can go without any lights (I have a 2004 donor/replacement bike too which don't have the switch).
Cold start as I remember always okay, it doesn't matter if the light switch on or off. But: if the bike was ridden enough and stopped, and the light switch is on, then:
1. starts normally
2. the starter turns so slow like a half turn


My second problem came up last Sunday, I rode about 200 kms away from home, filled the tank up, went back to the road, and the bike started to bwaaaaaa (like no fuel or spark stall) + check engine light, so I switched the kill switch off and on.. just to see that the display stay off no nothing...
I thought: fuse/battery/ECU , and fortunately only a fuse, but one of the two 30A fuses went off = nasty burn on it and the fuse box lid/cap slightly melted too.. (dont know the number of it now, but it is the third fuse from the bike's left to right)

So I started to look into it:

Third problem, mine uses just the left headlight for low beam and the right for high. After the R1 I sold, the light quality is ****. No wonder as the bulb get only 8-9 volts, so as Decosse's wrote in his headlight improvement post if 12,8volts = 1000 lumen, 10,5 =500, then I have a canclestick.

If I turn the ignition on, then there's an instant voltage drop between the battery (-) and the fuse box's terminals which at least 1 Volt, but if I switch the lights on, then some drops the same amount, some drops more, and the mentioned (30A) fuse gets hot.
Yesterday I checked my donor/second bike, and there's no significant voltage drop (a few tenths and hundredths).
So the problem(s) lie in the harness, but as I'm not an electrician, I don't have much clues where to start.
 
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#2 ·
Is your generating system OK?
I will caution that if you run with no lights (or even one light) you will probably burn up the Regulator much quicker - the R/R has to shunt more current when the bike is not consuming it. So contrary to popular perception the reliability of the Regulator is MUCH worse when the system load is smaller (that is how you are running - with either only one or NO headlights)

You may also not immediately see the problem with generating system if lights are not on (or only one on). I suspect your generating system has a problem and this is why your battery has insufficient current available to crank the engine properly (be careful attempting to start bike if it turns over very slowly with discharged battery - that will destroy your Starter Sprag Clutch!!!!!)


The fix to have both lights on is very simple - you just have to add relays to the two empty slots along side of subframe to enable the second light.
With both lights on, even at idle the voltage should be greater than ~13.5 (you will not get accurate indication if one or both headlights are off)

See the sticky thread for diagnostic & upgrade suggestion for generating system
 
#3 ·
Thanks DEcosse!

Then I will use the factory bulbs in the future too.
I read about motorcycle regulators a long time ago that (in time of carbureted bikes); so it is still true that more load is better - as it roughly saying converts the excess current into heat.

Now is the time when I could get into it, so in the last few days spare time I teared down the bike, unplugged every connector, and cleared all contacts. Still on it.
I will do your headlight perf mod, I bought thicker cables for it.

Will check the generating system too as I'm aware that sprag clutch issue.
 
#4 ·
hello,

some news:
I swapped my bike's headlights with the donor bike,unplugged and sprayed everything (connectors, switches, fuse holder, ...) w/ contact cleaner, plugged back, put the airbox and fuel tank back for the R/R and voltage drop @ headlights w/ engine running test, and put two relays into the two empty relay sockets.
Result: 11 (left hl) / 12 (right hl) volts instead the former 8-9 volts @ warmup idle (<1800rpm but falls steeply as the coolant warming up).
R/R works as it should, but I will check against the other (donor bike's) next time so I can compare the two slightly different units.

I still wanna do the headlight performance mod, but I haven't made a plan to do it fast (as I dont have much time and from next week the bike will be my only transport as the car will have a major body repair (rusted parts) so it has to be ready for use).

I will see that the very (too) slow crank issue with warm engine + light switch on still come up or it was went away.
 
#5 ·
Result: 11 (left hl) / 12 (right hl) volts instead the former 8-9 volts @ warmup idle (<1800rpm but falls steeply as the coolant warming up).
R/R works as it should, but I will check against the other (donor bike's) next time so I can compare the two slightly different units.
What does voltage measure across the battery terminals with the engine running at idle? This is what is important in determining if generating system working correctly.
Just because you swapped R/R does not necessarily mean it is good, nor that the problem may be with the stator.

So check the voltage across the battery (with the lights ON) and report that please.
 
#6 ·
Decosse, you're right, I have the problem.

R/R-1 (the used one):
Motor running, light switch off or just parking lights: 13,3-13,6V @ battery
lights on: 12,4V
R/R-2: same as above with lights off, lights on: 12,7-12,8 volts @ idle.
Stock wiring no charging mod.

If I twist the throttle a bit, then the steady light of the headlights becomes unstable - or just the vibration.

So voltage is less than the desired, at least by your thread of charging sys diag.
I'm not too happy as the bike will be my longer distance transport for the next weeks as the car needs some major body repairs/reneval.
 
#7 · (Edited)
I checked the R/Rs between the 4 pin and 3 pin connectors, with short circuit mode, the #1 gave ~450 value and no sounds with the 2 (I think positive) conn and nothing with the 2 other, and no sound of short circ.

Checked the connector which is the one the three pin connector goes from the R/R, all sounds short with the other two.

AC check: ****e. @ idle, one gives 3; one 4,2; and the last one 6,2 volts.. so it is far less than 20V and I had to bring up the rpms even for this values as after starting the engine they gave almost nothing just tenths, and with engine screaming way above 5000 they slowly climb up to or a bit over than 15-20 Volts.

THE above results wrong, sorry.
AC check, after I finally did it right: 18,8-19,2 Volts @ idle.
(my first attemp was in DC mode between the three stator wires /nothing/.. the second /the wrong above/ was AC mode, but one lead from the stator and engine case, finally after I read a kawa serv. manual too, I get it)
The voltage climbs up steadily with the rpm, so it looks better. Which points to my bike's wiring? (or the R/R as maybe I also did something unproperly).


Can that kill the R/R until I can replace it?
Do I need a new gasket if I want to swap the stator with my new-old donor bike's?
 
#8 ·
So...
1. stator looks good(?) with its 19V three phase AC delivery @ idle.
2. not fully understanding, if the R/R itself the problem, but it seems okay by resistance test and "I'd like to" blame the wiring.

Then I think the first move I should do is the mod and bring the R/R-s output directly to the battery.
http://www.triumphrat.net/daytona-d...charging-system-the-solution.html#post1023477

Then I should (should I?) see much better voltages with the lights ON and engine running, and also less warm/hot RR and also the 30A fuse that gets warm/hot too.
Right?

I hope I'll do it tomorrow as today I had and have to do other (unwanted) things than the bike.
 
#9 ·
Good news: I modded the wiring after the R/R's connector: new fused (30A) links to the battery. Result: 14.5Volts between the terminals.
:)
You guys are great who shared those mods! :)

The 30A fuse in the box which melted, I think melted because of the bad connection (maybe corroded and too loose), and I thought that I should do this mod first as this could get me stranded again, while dimmer lights not.
 
#13 ·
It should never get to 15V - that suggests a Regulator problem (unless your meter is just reading a bit high) - does it increase beyond 15 as you raise rpm even higher, or does it 'top out' at that 15V? If you have another meter, do a cross check to validate the readings. The really high battery voltage either corroborates that your meter is reading high - or is significantly over-charging from the high voltage!!

But the low voltage at low rpm that increases when you get the rpm up a bit possibly suggests a stator problem.

So I'm more leaning to meter reading a bit high and the stator possibly being bad - but those additional checks (another meter and raise rpm higher) will give better clues.

One more thing - can you check that the headlight bulbs are std 55/60W (not some high wattage types)
 
#16 ·
About the meter: yes it's quite possible to read higher it's just a cheapo base model, and I had problem when I've tried to measure resistance with it as I didn't get any steady results.
It has a potentiometer which let one to calibrate it's voltage reading. In our wall sockets there are 230V but the meter reads 236V.

So, to answer your question: 15 V was the topped out value, it wont get any higher.
I checked the stator earlier which produced ~19 AC Volts @idle which got higher as the rpms risen - all three wire, but if there's other methods to test it then I'll do it.

I will check the bulbs but the lamps are from a new, never used bike, so they should by the bulbs the factory put in them.
 
#17 ·
Hello,

TuneEcu also shows 15V w/ lights off, and 13.something w/ lights on, so I will check with the other R/R if that lower the 15V to 14.xx.

My next problem which didn't existed: the engine just shuts off sometimes while the clutch is disengaged/pulled AND the engine is warm (symptoms will come a few lines later)
I recently uploaded my older tune and I thought that maybe gives too much fuel @ idle, but leaning it a bit didn't helped with the problem, also the older tune was set to 1200 idle rpm but rpms fallen (warmed up) below indicated 1000 rpm , so I changed that too to 1300. Which is fine, no less than 1000 rpms anymore BUT the problem still exist:
1. stopped at traffic light/etc., idles fine in neutral, or 1st, but if I want to roll and give a bit throttle the rpm would drop instanly, so I have to give far more than a few hundreds, like instead of a bit 1300 -> 1500 , I have to 1300 -> 2000-2500, while it can roll in gear without throttle, so no low rpm fueling issue.
2. I go slowly in town, so the rpms are in the 2000-3500 range. No problem while rolling in gear BUT if I change gear: pull the clutch + roll off the throttle, sometimes the engine just dies.

I suspect the TPS, but then why does it happen only if the clutch switch is also in the 'mix'?
 
#18 ·
Hello,

1. stopped at traffic light/etc., idles fine in neutral, or 1st, but if I want to roll and give a bit throttle the rpm would drop instanly, so I have to give far more than a few hundreds, like instead of a bit 1300 -> 1500 , I have to 1300 -> 2000-2500, while it can roll in gear without throttle, so no low rpm fueling issue.
2. I go slowly in town, so the rpms are in the 2000-3500 range. No problem while rolling in gear BUT if I change gear: pull the clutch + roll off the throttle, sometimes the engine just dies.

I suspect the TPS, but then why does it happen only if the clutch switch is also in the 'mix'?
That's just an FI 'problem', map editing the values of that rpm range to stay open loop worked fine.


---

The next one (like I wanted to have another problem) is really electrical:
"click but no start, then starts fine"

I hit the starter button..."nothing". Then 0-2 more try and starts (cranks) normally.
(Almost the veeeryslow cranking thing which was ceased after the charging mod, maybe the two problem have the same cause.)
"Nothing" = after happened a few times I watched that I have clicking when I press the starter button, approx from under my seat, so:
1. will check the battery as maybe the charging voltage not enough when I ride as I ride with lights (because what Decosse suggested above but I haven't had the time & mood to check/repair it if I need to as I have too much thing to address), but I don't believe as after the above mods my battery got some tenth volts plus in it.
2. battery connections, starter relay, starter solenoid (I contact sprayed the starter switch yesterday but it made no difference).
 
#19 ·
The clicking you hear is the headlight cut relay; most likely the clutch switch is problem
Especially if you have adjustable lever - try opening span and see if that 'fixes' - if it does file a few mm off the end of the clutch switch pin
If not the switch throw check the harness from left bar switch - there is a splice about halfway down that can corrode & cause problems for clutch switch (& horn)


Sent from Motorcycle.com App
 
#20 ·
Thanks Decosse!

The only parts of the system I left out (from disconnecting & spray-cleaning) are that left handlebar sw connection about halfway to the frame neck, the starter solenoid, the clutch switch, and the right handlebar switches, so it makes sense to me.

My bike has a light switch but that not means that the relay you have mentioned should/would not click when I push the starter. I will check it tomorrow.

(Today I only made an experimental ecu map because I'm content with my last one in all but one area: I think it uses much more fuel @ cruise than it should by the exhaust tip; tomorrow a test ride will come, before that I will check the clutch sw & that connection; I am very grateful for the tips you gave before as my battery works better & I have real lights... :) )
 
#21 ·
My bike has a light switch but that not means that the relay you have mentioned should/would not click when I push the starter.
That is incorrect - the headlight cut relay will click regardless of the headlight switch
The fact that it is clicking also validates that the power from start switch is operating so no need to check there



Sent from Motorcycle.com App
 
#23 ·
Dash goes blank, speedo jumps... '02 S3

Electrical problem(s) come again...

Not long ago I changed my handlebar to clip-ons. But the problem I will describe, happened with the old config too, but not this long.

First symptom was that the speedo went blank, no zero, no nothing - then returned to normal.

This evening I rode home (~28 km) after I adjusted the clip-ons, which involved quite some tinkering with the throttle cables, clutch, handlebar switches. But after I started the bike, dash worked fine.
While I rode, the speedo started to jump from displaying the actual speed to display nonsense value, or display all the characters it could (like when I turn the ignition switch on), or simply went blank/blacked out. Sometimes the check engine light (MIL) also flickered while that happened. The turn/neutral/oil/etc indicator lights worked fine, while the tach (RPM indicator) went to zero WHEN I used the turn signals.
This time the problem didn't go away, I could only hope that it wont kill the engine/ignition before I get home. The engine management worked fine, so I think it is more likely a broken wire - bad connection problem around the front end, not an ECM malfunction.
The MIL didn't stayed on.

How much I hate electrical problems! :) :/
 
#25 ·
It was month(s) ago, and when the dash issue happened, the engine ran like before.
But I will try that too, thanks - I hope it will take me to the garage.

I suspect electrical issue because the tacho worked until I switched on the turn signals, after turned off them, it worked again. Or the combination of tune corruption and electrical.
 
#26 ·
Rode it to garage...:
started okay (no symptoms), rode with headlights off (no symptoms), later headlights on - nothing - also using turn signal speedo started to work erratic or blank fastly changing between the two. But this time tach was unaffected. Motor ran okay, no hiccups.
 
#28 ·
Update:
The day after last post's, there aren't any symptoms (headlights on + turn signal) even the speedo did not produced anything abnormal.
(because of the many constuctions in the city (Budapest) the car was inconvenient to use, I rode the bike)
Today I found the starter spin/spun somewhat slow, then I stopped to refuel (about 22 km later) starter spinned slower (about too slow) but engine fired up very well. Then at the garage it was a non-starter, voltage: 11,7 (a few days earlier, without any trickle charging between uses it was 12,7-12,8V). There were 1-2 light, maybe half-one sec. speedo hiccup without blanking when I used the turn signals, but apart from that nothing.

Of course I checked the stator, and the bad news: 0,1/0,1/0,4 Ohms (stator wire to battery or frame ground). I didn't tested the AC voltage (maybe I'll do but I don't see much point using the bike in this condition even if the AC voltages okay). A few days ago I checked with eng running, lights on: it was 13,8V.

So maybe the stator went bad independently and there's also a problem in the wiring, OR it caused both the dash problem and the battery drain (more precisely not recharged the battery so it lost 1V after 60-120km ride).
 
#29 ·
I haven't had much time, so I just stripped the rear fairings, take out the battery and put the charger on it. While I was there, I have found that the negative cable of my regulator to battery shortcut wiring failed and broken off from the battery connector ("quality" chinese jumper cable). Maybe I'm wrong, but I don't think that an open = non functional circuit is a very bad thing, but when I did that mod, it reducec some voltage losses. So without it, the oem harness become a weaker link again.
And that caused earlier some problems, like melting fuse insulations (without blowning the fuse itself), or even the fuse holder.

(thinking "loud": ) Looks like sooner or later I have to renew / replace the /or part of the/ wiring, no matter how I would like to avoid. Or exchange it with the other ('04) bike's harness and stator, which is new-old, never used, then later do the work on the old&used harness + uprgrade some bulbs to LEDs + upgrade wiring thickness to the headlights + add heated grips + add 12V socket...(inspired by DEcosse & the Other progressive minds).

Question is, that a 10+ years old (if it's still the oem) stator went bad by age&heat (lazy fault finding) or because some other problems which overheated & degraded it's insulation (methodical fault finding).
 
#30 ·
Update:
Not much.
I swapped the new stator from my '04 S3 donor, but haven't tried it as I want to check and if needed, repair (and/or modify) the wire harness. So I removed the harness, the ECU & the fuse box (these needed removal, I destroyed the plastic clips which hold the latter)

Problems I found:
- fuse holder burned a bit = bad connection = corroded
(kinda problematic the removal of fuse holders from the box: the plastic pins that hold the terminals too rigid, doesn't hold too good: possible that the fuse will push out the terminal from it's place - a fuse holder of ten pieces not too cheap; too bad that those sheet metal fuses ("MIDI" fuses) not applicable, I'd like a solid, bolt-on connection)

- one headlight connector male melted a bit = bad conn

- one of the ECU pins (2/C4) broke into the connector - prev. owner/service tampering?
I haven't found any function for it in the service manual, but around the pin the plastic discolored = there were some current flown (I've disconnected the battery weeks ago before disconnected the connector from the ECU / ECM, so I didn't broke it) Will see if it renders the ECU unoperable (removed the broken piece from the female connector).

Currently I don't do too much, with it, I want to make a good sized print from the wiring diagram, but because it's black and white, and not too good quality, I redraw it in colour before I print it, then make a custom pdf which is upscaleable without loss of quality.
 

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#31 ·
- one of the ECU pins (2/C4) broke into the connector - prev. owner/service tampering?
I haven't found any function for it in the service manual, but around the pin the plastic discolored = there were some current flown (I've disconnected the battery weeks ago before disconnected the connector from the ECU / ECM, so I didn't broke it) Will see if it renders the ECU unoperable (removed the broken piece from the female connector)..
2/C4 is ground connection - without that it will not operate.
=> ECU is throw-away
 
#32 ·
Thanks for the info, I will check the ECU and/or if there's someone who possibly can repair that pin. Funny that I used the bike with that broken pin without issues while it really had a very poor contact.

Long time passed, I just started to look after the bike - spring is coming... Replaced the stator, put back the cover with silicone sealant (liquid hi-temp gasket), but I don't trust it or my ability to use it properly, so I will get proper gasket.

I'm about to finish the colour version of the B/W S3 electrical drawing. If anyone interested in the final pdf (vectorised) version I will post it too - I think only minor changes, error left in it.
 

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