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FJ1100 85' dead coil solution

Started by mr blackstock, February 23, 2014, 06:31:23 AM

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mr blackstock

I started a new thread on my old problem so that future users with the same issue will get this search result first...

Awhile ago my spark plug leads no.2 and no.3 failed to spark.  No.1 and no.4 plug leads were fine.  I had the coil relay modification in place, so I disconnected this and re-plugged the coils back into the loom to test the wires, no problems there.  I tested all the connections back to the ignition module, no issues, I tested the wiring to the pick-up coils, no issues there.

I tested the sparkplugs and the caps, both were less than 6 months old, all were fine.  I tested the resistance on the coils, they were both outside recommended limits so I replaced them, I figured they were 28 years old, time for some new ones.  Still the problem persisted!  My next move was to replace the ignition module.  I bought one cheaply from a local wrecker and tried that....still the problem persisted! :dash2:

By now I was considering either putting a metal stake through her cursed heart or selling her on ebay for $20! :diablo:

I again looked to the wiring diagram.  Although I had already tested the wires, the grey wire from coil no.2, that feeds my problematic plug leads, also connected to the tachometer.  I unplugged the wiring blocks connecting the dash to the main loom and the bloody bike started!?!

On closer inspection the grey wire had a bad connection to the tachometer, a screw attaching it to the back of the dash cluster.  So if anyone gets the same issue, and exhausts all the other routes, try unplugging the dash wiring block under the front of the fairing, thereby disconnecting the grey wire.  if the bike starts the grey wire is the fault.  If the bike fails to start, go buy some expensive parts :greeting:

The bike now runs very sweet!  the new coils have brought heaps to the bike, also another member is sending me a digital ignition pack for trial.  Lillith will love me again...

Thanks to the members for lots of advice, problem solved.

Cheers, Gareth 
Squeaky wheels always get the grease...

Yamaha FJ1100 1985

ribbert

That's excellent news Gareth, and might I say, welcome to the world of auto elec. My motto with electrical problems has always been "2 days to find - 2 minutes to fix"

Just think of all those spares you'll have now, it'll keep the old girl running into next century. I actually carry a spare ignition box, coil and fuel pump on trips. I figure they are the only things that can't be jury rigged on the side of the road and are not readily available.

Well done on your persistence and troubleshooting.

Noel
"Tell a wise man something he doesn't know and he'll thank you, tell a fool something he doesn't know and he'll abuse you"

Pat Conlon

+1 excellent piece of detective work Gareth.
Can I copy and paste your post over into the General Maintence Files for easy future reference?
This is a good one.  Kudos!
1) Free Owners Manual download: https://tinyurl.com/fmsz7hk9
2) Don't store your FJ with E10 fuel https://tinyurl.com/3cjrfct5
3) Replace your old stock rubber brake lines.
4) Important items for the '84-87 FJ's:
Safety wire: https://tinyurl.com/99zp8ufh
Fuel line: https://tinyurl.com/bdff9bf3

mr blackstock

Cheers guys,

I updated the diagram I did when I first did the coil relay modification.  You are welcome to use the post, I hope it saves someone from a lot of frustration.  One little bloody wire....

Cheers, Gareth

Squeaky wheels always get the grease...

Yamaha FJ1100 1985

Arnie

Gareth,

Is there some reason you used a 2pole (87 & 87A) relay?
Wouldn't a 'normal' 30A 4pin horn relay have worked just fine and fed both coils?

FJ_Hooligan

Isn't 87 normally open and 87A normally closed?
DavidR.

mr blackstock

G'day,

yeah, I could have used the four pole relay, I think I used the five pole as it was what I could find on the shelf.  I was new to relays at the time, and probably did not know the difference.

I do not think 87a and 87 are different, this setup works sweet on the bike.

I gotta take the bike for a spin, try out the new parts!

Cheers, Gareth
Squeaky wheels always get the grease...

Yamaha FJ1100 1985

FJmonkey

The glass is not half full, it was engineered with a 2X safety factor.

'86 Ambulance - Bent frame, cracked case, due for an overhaul
'89 Stormy Blue - Suits my Dark Side

Charlie-brm

It works sweet the way it is because according to that diagram, the power is coming through the relay even when the bike is turned off. When no trigger power is going to the relay, 87a is live to the battery, as you have it shown on the same terminal at the starter. When the motorcycle, and hence the module powers up, the relay activates and now the 87a terminal is taken out of circuit while the 87 terminal is live to the battery.

I'd rethink that wiring, seriously. Chop the 87a altogether. Play around with relays some more to get the functions comfortably figured out. Use 12V bulbs or a test meter to figure out what's going on inside them.

Quote from: mr blackstock on February 24, 2014, 09:37:06 PM
G'day,

yeah, I could have used the four pole relay, I think I used the five pole as it was what I could find on the shelf.  I was new to relays at the time, and probably did not know the difference.

I do not think 87a and 87 are different, this setup works sweet on the bike.

I gotta take the bike for a spin, try out the new parts!

Cheers, Gareth
If someone wants to see any images I refer to in posts, first check my gallery here. If no bueno, send me a PM. More than glad to share.
Current Model: 1990 FJ1200 3CV since 2020
Past Models: 1984 FJ1100 - 2012 to 2020
1979 XS750SF - 2005 to 2012

twangin4u

Quote from: Charlie-brm on April 04, 2014, 11:03:59 PM
It works sweet the way it is because according to that diagram, the power is coming through the relay even when the bike is turned off. When no trigger power is going to the relay, 87a is live to the battery, as you have it shown on the same terminal at the starter. When the motorcycle, and hence the module powers up, the relay activates and now the 87a terminal is taken out of circuit while the 87 terminal is live to the battery.

I'd rethink that wiring, seriously. Chop the 87a altogether. Play around with relays some more to get the functions comfortably figured out. Use 12V bulbs or a test meter to figure out what's going on inside them.

Quote from: mr blackstock on February 24, 2014, 09:37:06 PM
G'day,

yeah, I could have used the four pole relay, I think I used the five pole as it was what I could find on the shelf.  I was new to relays at the time, and probably did not know the difference.

I do not think 87a and 87 are different, this setup works sweet on the bike.

I gotta take the bike for a spin, try out the new parts!

Cheers, Gareth

Better yet.. Pop the top off one of them and witness the points and terminals respectively.

You'll get an " ah-ha!" Moment

FJ_Hooligan

If you want to play, a 9 volt battery is enough to activate a relay. 
DavidR.