Electrical issues pt 2

Hello all. This is in my other thread, but since I have troubleshot some new things in it, and because that thread was getting rather long, I am starting a new thread on this.

So, on my bike, I have an electrical issue that is plaguing it currently. I get a very weak to no spark (might as well be no spark because it will not fire the engine). Multimeter says that both my ignition coils are good, so where do I go from here? My ICM? Where is that located, and if that is to blame, what kinda cost is it to fix? What if its not the ICM? Then where? I know that the rotator and switch assembly is working properly. Need some help to see where I go from here, please...

 

I'm assuming you're refering to the TCI, from what I can find it's located beside the fuse panel under the seat on your model. There is no test for it, you replace it if everything else checks out okay.

However, if you look at these two links, people have been tearing into them for a rebuild. The second link is not a XJ TCI but still has good info on the subject.

http://members.tripod.com/dave_jack/id41.htm

http://www.jetav8r.com/Vision/TCIRebuil ... build.html

Here is what the Yamaha manual has on a trouble shooting flow chart for the ignition system.

Check entire ignition system for connections. - Poor connections - Correct

Check battery for voltage and specific gravity - Low voltage & specific gravity - Correct

Check fuse and fuse connections - Weak connection or open circuit - Correct connection or replace fuse

Check resistance of ignition coil (primary and secondary) Primary 2.5 ohms +/- 10% @ 68 degrees F Secondary 11K ohms +/- 10% @ 68 degrees F - if other than specified - replace ignition coil

Check pickup coils for resistance 650 ohms +/- 20% @ 68 degrees F - if other than specified - replace pickup coil

TCI unit is faulty, replace unit

 

Are there aftermarket TCI units, or do I need to go salvage?

 

A couple of other things that I didn't add on last post......

The plug wire caps should be off when testing the coils secondary resistance.

Each cap should have it's own resistance of 10K ohms.

The spark plugs listed in the Yamaha manual for this model are D8EA NGK's or X24ES-U ND's. The plug gap should be 0.024 to 0.028 inch.

 

I'm not aware of aftermarket units, which means ebay or salvage yards if you have one close by.

 

I doubt you need to replace any components just yet.
We need some feedback here on some of your tests.
How are you checking for spark? If you ground the plug against the head and look at it as you crank the fully charged battery to the starter, the spark you see is NOT gonna be very impressive. You will see a quick blue flash, but what are you using as a determination that the spark is "weak" Any spark there is probably NORMAL
Take out all the plugs, wrap some wire around the threads and then ground them all to the battery negative post. Now the engine will spin really quickly since there is no compression to work against.
Now observe the plugs in a darkened area, so you can confirm that each one is getting a spark.
What are the results of that? Please report.
What do your spark plugs look like? are they wet when you remove them?
are they completely black? Please report
While you are cranking the engine, are you smelling fuel?
Roll up a section of white paper towel so it can probe down the plug hole into the cylinders. Poke it all the way down til it touches the top of the piston and rotate it around. When you pull it out is it wet with gasoline?
Please report.

Dan

 

If there is any spark at all (normally there isn't, or its too weak to see), it is hard to see regardless. It's as though its "missing" the spark normally.

There is no char whatsoever on them because it is not firing at all. I do have gas (you can smell it all over the place. The plugs are a lil wet when I do take them out, and with a papertowel, it comes back out damp. These plugs are new, gapped at .028 and still look like they came out of the box.

Yes, the engine is getting fuel, and can be smelled fairly obviously.

 

One listing on ebay right now, says he has two units......
http://cgi.ebay.ca/yamaha-seca-xj550-ig ... dZViewItem

I would ask him for the numbers stamped on the blue label and compair with yours before purchase.

 

Well, now I am not so sure its the TCI unit. I got my Clymer book today on this bike, and according to it, here are what my outputs should be on my ignition coils:

when testing just the leads into it (not from the cap), my ohms should read 2.5 +-10% @ 68F. When I read, on both sides, I get 3.1 and its about 90F here. Is that proper?

When I tried to read ohms from one lead to any cap, I cannot get a reading. I am sure now that I am doing it right. This is happening on both sides. However, I know there has to be some sort of route to the plugs from the ignition coil because occasionally I will see them spark (though weak and rare)...

 

Have you taken the boots (or caps) from the leads? The ones on the outside (1&4 cyl) should read about 5,000 ohms (5K ohms) the inside two (#3 & 4 cyl) will be about 10,000 ohms (10K ohms) be sure your meter is on the correct scale. measure from the position the plug tip goes into to the other end that connects to the large plug wire.
Can you see the wire inside that large plug wire? You may need to trim a tiny bid of the thick insulator from it to see the wire. Is it in good clean condition?
Try cranking the engine while holding the spark plug lead close to the head. Does a spark jump that? Test all the leads that way.
When testing, make sure the other leads are connected to a grounded spark plug.
You cannot make these tests very effectively outside in the daylight.

 

It sounds like the engine is flooded. It won't start like that. Pull all the plugs, Use the paper towel trick to dry out each of the cylinders. Make sure the choke is OFF and twist the throttle full open. Crank the engine for a minuet to let air rush thru it and out the plug holes. When it's dry inside the cylinder, shoot a quik shot of ether down the plug hole & put the plug back in. Do this one at a time to each of the cylinders, the hook your spark plug wires back up and fire it up!!!

 

I remove the caps from the plugs, but I don't see how to get the plug wires removed from the coils. There is no corrosion on the part of the caps I can see.

 

The wires are not removable from the coil body, not to worry. If there is no sign of corrosion on the caps, you should be good to go.

 

So then I am right, my coils themselves are bad because my ohms readings are bad? Have you guys ever heard of both coils failing at the same time, or should I also suspect my Ignitor might be bad as well?

 

No I don't think your coils are bad.
Have you checked them as I described above?

"Can you see the wire inside that large plug wire? You may need to trim a tiny bid of the thick insulator from it to see the wire. Is it in good clean condition?
Try cranking the engine while holding the spark plug lead close to the head. Does a spark jump that? Test all the leads that way."

Tell us the results of that test.

 

Im not sure I understand what you are proposing here. What exactly do you mean? If I cut back the insulator, won't that then jeopardize the integrity of my wires afterwards so that they are more prone to corrode?

 

You must screw the angle connector off of the spark plug wire. Have you looked at the spark plug wire? Can you see the copper wire inside the insulation surround?
The end of the angle adapter must screw up into the center and contact metal to pass the voltage down to the spark plug. If there is any corrosion in there it introduces resistance, which drops the available voltage to the plug.
If you need to trim a bit off the end of the insulation to see the wire better (I'm talking no more than about 1/8 of an inch or so, you won't be harming anything.
Let me ask again, can you see a spark come from the center wire to a ground such as the cyl head when you hold that plug wire near the head while cranking your starter with a fully charged battery?
If so, screw the angle adapter back on, stick a screw up into the end that the spark plug attaches to so you can test again for a spark.


Dan

 

did you ever remove the coils and shine up the area where the bolts go thru the frame
also check the battery neg to the frame and to the engine
when you look for spark, look down inside the plug for spark that never makes it to the gap

 

If you have an inductive timing light, you can use that to determine if sufficent current is being generated through the secondary (ignition) lines.