HELP!!! Electrical problems.

I'm rebuilding the XJ550 Maxim after the paint job... It was running fine before. Now that I put back all electrical stuff it don't start. Honestly its a nightmare... So the battery is good. All connections in right order (I think). The starter solenoid is good (tested today).
Now the fun part:
Everything's connected, ignition on. I can hear the relays click on. BUT the diode unit gets hot. Plus when pushing start button nothing happens. The diode unit just gets hotter and hotter.

Ignition ON, ignition coils disconnected from the system. Diode unit cool. The start button still no signs of anything...

Ignition ON, everything's connected, diode get's hot, start button no answer BUT I pres the side stand switch, at that moment the spark comes out from spark plugs. WT*???

And by now I think the diode unit just burned...
Please guys any help.
Diode unit- I mean this thing http://thumbs1.ebaystatic.com/d/l225/m/mUW33JZ15YIeEqYnNMmMOJw.jpg
What is it for?

 

err vague recollections of the side stand circuit allowing the power that would usually go to the coils, to instead divert to earth.
Thus - if the side stand is down, you get no power to the coils, saving you from an ungraceful exit from bike ownership.

So. the endlessly heating diode doesnt sound promising, but what you describe about the diode/side stand switch makes sense.
I'm sure you've seen this little bit of awesome: http://frankjohansson.com/stuff/xj550/XJ550ElectricalDiagram.html

I burned a diode once, easy replacement if you know the size (i'll see if I wrote it down anywhere)

btw, diodes only allow voltage to go one direction, thusly useful for diverting currents as described above

 

On my Maxim there is just a diode block. They all sealed in one unit. A little confusion, what do you mean 'if you know the size' ?

 

are you sure you got the relays back in their proper locations? they each perform differently.

bleedingoxide, that is one cool wiring diagram.

FU

 

I think "bleedingoxide" means he replaced a burnt out diode, from INSIDE the diode block.
stu

 

The diagram is fantastic.
Yea, I am sure with the relays. Half of them wasn't even disconnected at all...
Any ideas how to get into the diode block? Which is sealed in rubber.
'err vague recollections of the side stand circuit allowing the power that would usually go to the coils, to instead divert to earth.'
Does that mean that the side stand circuit wires are damaged somewhere and touches to earth?

 

Just replace the diode block and harness---- it's only about 3" of wires between the block and the clip

 

I had a problem like that and make sure you check that you did not hurt the solenoid up backward

 

Sorry hook the solenoid up backward

 

i think i remember something about unplugging the safety relay defeated all the safety stuff.....but that might have been another bike, but if the safety relay isn't really the safety relay that won't work.
when a diode goes bad usually it will open, like a fuse, and not conduct at all. so if it gets hot it should still be good.
your very, very sure the relays are in the right place

 

Polock gave me this tidbit a while back and it helped diagnose my roughly related situation:

"unplugging the safety relay on that bike isn't all there is to it. there should be two red/white wires in the safety relay plug, they need to be connected for the solenoid to work. just put some wires in the connector.....safety relay is out of the picture.
if you think the battery doesn't have the beans to start it, you could try to push start it.
seems like your loosing a lot of electrons on the way to the tci. try this, unplug your headlight, so you don't kill the battery this might take some time.
put your charger on the battery and the meter on the tci where you measured the 9.5, 10.2 (r/w---b) now try r/w to a good clean frame.
should be the same. now wiggle all the connections on the fuse box, fuses and any others you find handy, see if one of them gets you more volts"

It's from this thread, maybe there is some further clue here: http://xjbikes.com/forums/index.php?threads/weird-no-spark-condition.46846/

 

The diode is gone for sure.

 

The headlight is disconnected. Safety relay - Start circuit cut off relay?
Hmmm, will try to do that as soon as I will get another diode pack. Logically if the side stand wires are messed up somewhere (Because it gives little spark from spark plugs every time I press it) then by getting the safety relay from the picture I should have everything working?

 

i just found my 550 book. it looks like the same jumper thing works on it too. the book i have doesn't say how to test the diode pack. if it did, making one would be pretty cheap
yes, Safety relay = Start circuit cut off relay

 

Yeh sorry, had to cut through all that nasty rubber.
Heres pics of whats inside (mebbe just recreate it) the middle diode is burnt up.

regarding Diode size, I think I got my info here: http://xjbikes.com/forums/index.php?threads/old-yamaha-diodes.32519/

 

Again, if it's bad just replace it. Either from a parts bike, or for the roughly $30-$35 buck you'll spend on a new one, you'll waste more than that in time, travel, and parts just to go to Radio Shack and get the parts to make your own.

Just get another one.

Dave F

 

Thanks so much for this pic. I am not yet 100% sure, but I think I have exactly same diode (sky blue wire) burned.
Alright then. Next step get diode functionally, then try to bypass safety circuit, see where that will get me.
Thanks allot guys for help. Any other ideas please share

 

[QUOTESo ="BleedingOxide, post: 434281, member: 13915"]Yeh sorry, had to cut through all that nasty rubber.
Heres pics of whats inside (mebbe just recreate it) the middle diode is burnt up.

regarding Diode size, I think I got my info here: http://xjbikes.com/forums/index.php?threads/old-yamaha-diodes.32519/
[/QUOTE]
So I have the same diode getting really hot. It is not burned yet, so I just solder it back to place and it works, but again gets really hot quickly. Maybe you remember what caused this burn out for you? Any clue?

 

The diode for the side stand relay allows the side stand relay to energize when the bike is in neutral (side stand down) opening a set of normally closed contacts, which then enables the TCI. The side stand relay coil is about 100 ohms so theoretically there should be approximately 120ma of current through the diode, not near enough to get it hot.

Other than a miswire (incorrect plug hooked up) or shorted pins somewhere (smashed bent pin in a connector), there should only be one other reason it would overheat.

The side stand relay is defective diverting 12v directly to the diode bypassing the 100 ohm coil or the coil has overheated and shorted. I also looked at incorrect relay, and don’t see that causing this problem as the coil / contacts for the starter cutoff relay and headlight relay are arranged such that they should not divert 12V directly to the diode. I would still check those as suggested earlier just to be sure.

Note: The side stand relay is identified by a blue dot on the relay, and the mating harness should have blue tape wrapped at the connector end to identify mating connector.

Note: The head light relay is identified by a yellow dot on the relay, and the mating harness should have yellow tape wrapped at the connector end to indentify mating connector.

Note: The starter cutoff relay is identified with the number 4H7, I don’t believe it has any color coding on the mating connector.

As for a miswire one possibility that I am not sure of on the 550 is the proximity of relay and TCI. The 4 pin mating connector on the TCI is the same as those on the relays, so be sure the TCI and relay connectors are not reversed if they are in close proximity on the 550. TCI mating connectors should be marked with red tape.

Checking continuity for side stand relay coil and related diode:

Remove the battery plus cable

Turn on the ignition switch and kill switch on – fuses must be good.

Sett DMM to check continuity, place the positive lead on the battery plus cable (not the battery)

With the side stand relay installed, place the DMM negative lead on the blue/yellow wire at the back of the mating connector for the side stand relay – it should read approximately 100 ohms - side stand relay coil.

Note: This same blue/white wire should also ohm to ground if the side stand is up

If the reading is considerably less, start isolating by pulling parts and checking connectors.

 

Diodes increase in resistance as they age. That is the main cause for an old diode to bun out. Checking other components is a good thing to do anyway, but i'd still recommend using a new (not 30 year old used) diode.

 

So I by passed the said stand switch by connecting to wires and put them to ground. That stopped the diode to get hot. And the starter came back to play.
But without any spark. Plus the starter sounded really heavy, like it's not getting enough power. I disconnected the ignition coils and starter was spinning freely.
Other thing when ignition coils was connected the ignition unit was getting a bit warm
With the ignition coils disconnected I have 11.67 Volts at TCI (Red-White with Black) With the starter engaged drops to 6.70 Volts.
With the coils connected 8.16 Volts and 5.18 when start button is pushed (but starter does not engage)

Now as I have by passed the side stand switch. Everything seems to be working even if I disconnect the diode unit. ???

After a while I noticed that the starter solenoid sometimes clicks few times before engage. And the positive wire from the battery to solenoid gets hot.
Could it be that my starter motor is defected? I checked the connection point on the starter and it came up as negative. Is that how it suppose to be?

 

Well, for one... the low voltage sure makes me think either your battery is bad. ( I dont care whether you said the battery is good, or new, etc....) you have no idea how many " new" and "good" batteries I've seen that were actually. BAD!!! Or else you have a really nasty corroded positive lead from battery to solenoid, or solenoid to starter. Or, a green-out ground wire.

You could also have:
A defective starter
A defective regulator
A defective ignition switch
A wiring short

 

I know what you mean about the battery... Read throw all electrical threads and, so yea, I agree about the battery.I am starting to think that the starter is defective.
Does the connection on the starter (when the starter is installed) should read as negative?
Plus I noticed that if the ignition is on and I am trying to connect the ignition coils, there is a bit of spark in the connector, like a short circuit.

 

Wire to Battery post is POSITIVE. Casing is grounded to engine, which is grounded to battery ground through ground strap, frame, and/or battery negative wire.

If your getting neg at the starter post, you either have fried starter, or the post insulator is broken and the post is grounding/shorting out. That will cause all kinds of overheated wire issues very quickly -

 

Thanks for help hogfiddles! I'm fingers crossed now, that the problem is starter. I will get my hands on it and will see what happens.

 

So I disconnected the starter completely from the system, but still nothing changed. The interesting thing is that with the ignition ON, the wires that are going to the ignition coil (grey and red/white) grey - red/white + right?
But when I connect the grey wire (-) to the ignition coil connector, all the sudden both grey and red/white from the coil turns to negative. As a result, trying to connect the red/white wire from the harness makes a short.
Is this how coils work or what?
But then again, both coils go bad at the same time?

 

The Red/White (Ignition Circuit) wires are the high side (+12V) power to the ignition coils. This is battery power that is routed through the main fuse, ignition switch, ignition fuse, kill switch, and then directly to the ignition coils, TCI, starter cutoff relay, side stand relay, and oil indicator lamp. It also drives the starter solenoid coil when the start button is depressed if the starter cutoff relay is in a safe condition with closed contacts. This line should always stay at battery voltage (minus residual drop) or approximately +12V.

The orange and grey wires for the coils route to the TCI, and are used to drive the coils to produce spark. The orange wire at the coil that routes to the TCI is for cylinder 1 and 4, and the grey wire on the other coil is for cylinders 2 and 3. When the ignition switch is turned on, the TCI will power up for about 3 seconds sinking current through the coils. If no input is sensed at the input (pick-up coils), the TCI will go to standby mode so the coils will not be overheated by constant current flow.

Having a negative voltage with the battery connected properly is not going to happen. Perhaps you could be more specific on "exactly" where you are applying the meter probes. For example, with the DMM set to measure DC Voltage and the positive red lead connected to the Red/White wire at the ignition coil and the negative black lead connected to the battery negative terminal I read +11.5V.

As for the coils causing shorts it is possible that they could short to ground if they were seriously overheated for some reason. Since there is 12V tied directly to one side of them, then a near short to ground could conceivably cause some strange issues. You could easily verify them by doing a resistance check on them. Disconnect them from the main harness, set the DMM to measure resistance and check from the red/white to orange for one coil and the red/white to grey for the other coil, this is the primary side of the coil and it should measure approximately 3 ohms. With the main harness still disconnected check each red/white wire to ground for each coil, it should read open.

 

I checked the resistance, one was 02.7 other 02.8 , so I guess coils are good. Then the only thing left faulty TCI?

 

Or regulator, or even Something else

 

I made some pictures so you can easy see what I meant. The voltage is low but if I disconnect the other coil, voltage goes almost 12V. So in pictures the black lead of DMM is on negative battery post, and rest you can see.

 

So what is the battery voltage if you measure across the battery with both coils hooked up? The voltages in all the pictures looked normal other than being too low.

 

I will check the battery voltage later today. But you said you have 12 volts at the red/white wire and I have only 9.70
And the main thing, does it suppose to be like when I connect the red/white wire to the coil, the grey wire from the coil shows same voltage, you can see it in pictures. I just don't get it.

 

Yes the red/white wires should be battery voltage or approximately 12V. It is normal to be about one volt less at the ignition coils because of the accumulated voltage drop on the high side that occurs along the way through the wiring, connectors, and switches - main fuse, ignition switch, ignition fuse, kill switch. Any of those could cause excessive drop if they are not in good working order. A weak battery or poor connection at the battery terminals should be the first place to address when noting low voltages.

This is a normal condition. The TCI connects to the grey wire. There are transistors inside the TCI that pull this point to ground at a rate determined by engine rpm. You can think of these transistors as a simple switch, when the transistors conduct (switch closed) the grey wire is pulled to ground and current flows through the coil. When they are not conducting (switch open) the grey wire will float at 12V and no current is flowing through the coil.

 

Alright then... When the coils are connected, and starter button is pushed nothing happens just the coils getting warm and the bottom of TCI is getting warm too. The safety relay is by passed, but if I connect the relay, it gets warm too. Any Ideas what could cause that?

 

So what is the battery voltage, was it OK? If so, what is the voltage measurement to the coils at the red/white wire?

If the battery voltage is OK and the voltage is low at the coil red/white wire the most common failure is the fuse box itself if it has not been updated. The terminals in the fuse box deteriorate with age and often break and develop resistance causing voltage drop.

Remember back on page one of this post that a when the ignition switch is turned on the TCI should only drive the coils for approximately 3 seconds, and then switch to standby mode, so the coils should not heat up if the bike is not running. Not sure if this feature could be defeated by low voltage on the ignition circuit, but that is a possibility. So need to check the battery and ignition circuit voltages and let us know what you get.

Is this still the current condition but now the starter is not working?

Did you ever go back and double check the relay/harness connectors installation per the color codes referenced in the reply on page 1?

How about checking the side stand relay and related diode suggested on page 1, did you ever do that also?

 

So as for today, I triple checked all connections and wires, cleaned the start ant start cut off switch. Cleaned connectors as well.

With everything connected and ignition on the ignition and start circuit just heats up. The TCI, main and ignition fuse, ignition coils, run/stop switch, start cut of relay... They getting hot with ignition on and pushing start button. The starter does not engage, unless I tap it with a spanner or something, just a little tap and it starts to spin, but no spark.

With the ignition coils disconnected, nothing heats up, starter spins as it should, obviously no spark.

I checked voltages at some points to give you some readings.

Everything connected:

Battery: 12.36v ignition on: 12.01 start: 11.97v

Main fuse: 12.36v ign. on: 11.34v start: 11.11v

Ignition fuse: 10.30v start 9.98v

TCI 4pin connector red with black: 8.42 v start: 7.50 v

Right ign. Coil red/white to battery negative 8.52 v start: 7.70 v

Left ign. Coil red/white to battery negative: 8.63 v start: 7.76 v


Ignition coils disconnected:

Battery: 12.36v ignition on: 12.20 v start: 11.20 v

Main fuse: 12.36 v ign. on: 11.94 v start: 7.60v

Ignition fuse: 11.53v start 7.30v

TCI 4pin connector red with black: 11.39 v start: 6.50 v

Right ign. Coil red/white to battery negative 11.48 v start: 6.60 v

Left ign. Coil red/white to battery negative: 11.40 v start 6.60 v


Everything connected, start cut off relay by passed:

Battery: 12.37v ignition on: 11.90 v start: 11.13v

Main fuse: 12.25v ign. on: 11.26 v start: 7.50v

Ignition fuse: 10.25 v start 6.76 v

TCI 4pin connector red with black: 8.35 v start: 5.20 v

Right ign. Coil red/white to battery negative 8.70 v start: 5.45 v

Left ign. Coil red/white to battery negative: 8.76 v start: 5.46 v


Ignition coils disconnected, start cut off relay by passed:

Battery: 12.36v ignition on: 12.12 start: 11.15v

Main fuse: 12.25v ign. on: 11.90v start: 7.80v

Ignition fuse: 11.55 v start 7.20 v

TCI 4pin connector red with black: 11.34 v start: 6.40 v

Right ign. Coil (from connector) red/white to battery negative 11.52 v

Left ign. Coil (from connector) red/white to battery negative: 11.52 v


Right coil primary resistance: 02.9 ohms

Secondary: 11.6 ohms

Left coil primary: 03.0 ohms

Secondary 28.8 ohms

DMM set on 200k ohms.

The left coils is from xj900
Damn.. Forgot to check side stand relay and diode

 

So when you get back to it to check the side stand relay / diode do this also:

With everything hooked up check the voltage on the coil grey and orange wire. Wait a least 3 seconds before checking after turning the ignition switch on. The voltage should be equal to the voltage on the red/white wire. If it is the same, then the TCI is doing its job and not driving the coils with the bike not running. If the voltage is near zero on the grey and orange wires then do this:

Turn the ignition switch off, disconnect the coils and check continuity on the engine harness connector grey and orange wires to engine ground or battery negative. This should be a high resistance. If you get a low reading then the drive transistors in the TCI are damaged, which would cause excessive load on the ignition circuit and would produce excessive heat in the TCI, ignition coils, and possibly the wiring / switches that supply them.

How are you doing this? Is it by installing a jumper in the starter cutoff relay mating connector shorting the Red White to Red White?

Did you mean Red White or is there really a Red Black connected to the TCI?

Secondary resistance should be in the Kohms, is this a typo?

I am quite confused about the main fuse voltage being low in all the "start" cases except when everything was connected, yet the battery voltage during start is OK in all cases. If these are accurate measurements then there would have to be a very poor connection in the main fuse circuit, and depending on which side of the fuse you measured on, a poor connection at the fuse box or the connections leading to the fuse box. Normally, the first guess here for those low voltages on the main fuse during starter engagement would be the battery, or in rare cases a defective starter. Next on the list would be the fuse box itself, has it been updated? The fuses should not get hot.

Also, the bad fuse box or connection is contradicted by normal voltages with the "ignition on" and the main fuse voltage is OK. Current through the main fuse will not change much when simply cranking the bike. The only added current would be the TCI coil drive and the starter solenoid engaging, which is only about 5 amps... so bottom line part of the problem looks like a bad battery. How old is the battery?

 

Finally managed to get my hands on the bike. So for the side stand I had 54 ohms, and after other checks and playing around with wires I had 88.6 ohms.
So with everything hooked up I turned the ignition on, after about 3 seconds the voltage on the grey wire was 1.46 V, orange wire was 1.26 V, while on red/white wires voltage was 8.45-8.40 V.
Then I checked the resistance from engine harness grey and orange to ground and there was no reading on DMM at all.
To buy pass the safety relay I disconnect it and jump two red wires together.
TCI 4 pin I meant to say that one wire is red and other is black.
Yes, secondary resistance is in Kohms.
The fuse box is getting upgraded this weekend maybe.
And about the battery, as I read throw all electrical threads I see that it is often a problem. For now I am using a good car battery.. But to make sure I had my car battery properly hooked up. Starter was spinning like mad (ignition coils disconnected) but I didn't measure the voltages, judging from the starter there may be some more volts with a new battery. But when ignition coils connected everything goes to same state

 

54 ohms is suspicious, 88 might be OK. I would pull the side stand relay out and measure it separately. Here is a diagram to go by:


3-31-15 - edited description in bottom test box

Check the relay coil from R/W to L/Y, should be approximately 100 ohms.
Check the normally closed contact from B/W to B, should read near zero ohms.
Check the R/W to B/W and B, should be open.
Check the B/W to L/Y, should be open

Not a good indication, both ignition coils are being driven continuously. I would try disconnecting the 6 pin connector on the TCI to see if you can get the orange and grey to match the voltage on the R/W wires at the ignition coils. If the orange and grey at the ignition coils stay low, then might be time to try another TCI. If they go high, then do a continuity check on the pick-up coils:

To check the pick-up coils do this on the TCI six pin mating connector:
Positive probe Orange wire, negative probe to black wire, should be 650 +/- 20%
Positive probe Grey wire, negative probe to black wire, should be 650 +/- 20%
Positive probe Orange wire, negative probe to chassis, should be open
Positive probe Grey wire, negative prove to chassis, should be open
Positive probe Black wire, negative probe to chassis, should be open

Checking the pickup coils and ignition coils one more time before installing another TCI would be a good idea to minimize the risk of damaging the replacement.

This is an indication that at this time the side stand relay was doing its job, and the TCI was responding to the enable / disable command. Normally, a spark would not occur from this, however in your case because the coils are constantly being driven then each time the side stand went down the TCI would disable interrupting coil current, which then produced the spark.

This link may help also. It is from the DIY section explaining the operation of the ignition circuit:

http://www.xjbikes.com/forums/index.php?threads/how-to-ignition-troubleshooting.21932/

 

So I am waiting for another TCI to arrive.
If I by pass the safety relay will that remove the side stand from the circuit as well?
I'm thinking to remove all surrounding electrical circuits, and see will it work. If everything starts to heat up again, then obviously something from ignition circuit is faulty

 

So did you have a chance to check out the side stand relay and pick-up coils as suggested?

Bypassing the safety relay will not remove the side stand from the circuit. All the associated wiring is still in place so when the side stand is raised and lowered and the switch actuated it will still either apply ground or remove ground to the L/Y wire.

The side stand relay can be removed for testing purposes to eliminate that portion of the safety circuit. With the side stand relay removed and ground no longer applied to the TCI enable / disable terminal (B/W wire) the TCI will always be enabled.

Before connecting another TCI I would also suggest checking the voltages on the TCI mating connectors to make sure they appear normal.
4 pin connector:
R/W power to TCI so approx. 12V
B is ground so should be zero
O for one ignition coil primary should be approx. 12V
Gr for the other coil primary should be approx. 12V

6 pin connector:
There should be no voltage present on any of the wires

 

Ahhhhh... Finally.. I received the TCI. Anyway I gave the bike to a man with bit more knowledge. His conclusion was that the wires from pick up coils caused short by touching the frame. Well the wires are old, there is some splits in them. MAYBE somehow they touched the frame. Could that be the reason for TCI failure?
I checked everything as suggested before plugging the TCI. Well everything seems to be good enough, so I plugged the TCI. Nothing is heating, good healthy spark (didn't even expect such a good spark)

 

Good to hear all appears better and hope it stays that way.

Was this detected by actually checking continuity to ground and noting a problem? Or, was it just speculation after noting the condition of the wires?

This is a tough one to answer... I am not aware of any schematic diagram that exists on the TCI, so without that I can't say for sure one way or the other. I could only speculate that the TCI biases the pick-up coils in such a way that grounding the pick-up wires might cause some damage. The pulse from the pick-up coils per SQL Guy can be 100 volts peak to peak, so be sure to take care of those wires and verify they are properly insulated from ground. If they didn't cause the problem, they could certainly contribute to a poor running bike.

Have you started and ridden the bike? I would be very methodical about the order of things on the first run, just in case a particular event causes a repeat of the condition.

 

Where did you get the TCI? New, used, rebuilt, aftermarket?

 

If you're getting sparks flying, that would seem to indicate you have a pretty good short somewhere--- you may have fried the tci too

 

Oops.... Didn't realize that I was still on page 2---- just saw page 3...... Carry on

 

Used, from ebay

 

I think it was more speculation than fact about the wires.
I haven't start the bike yet. Just putted electrical part back. Tomorrow exhaust goes on and the try to START. Any advises on how to prevent any disaster?

 

My suggestion would be after assembly is to do the voltage and continuity checks on the TCI mating connectors again before connecting the new TCI. Just make sure no strange voltages or unusual resistance readings are noted, particularly resistance to ground. For the voltage checks, exercise the starter cutoff relay and side stand relay by taking the bike in and out of neutral, pulling the clutch in, and raising and lowering the side stand. With the TCI still disconnected, verify the you can bump the starter;
first in neutral, then in gear with the side stand up and clutch pulled in.

And, back to your original problem of the diode block overheating, make sure it is cool to the touch... hopefully you have a new replacement. If any of the conditions don't check out then don't connect the new TCI until the problem is solved.