Triumphrat

05-29-2005, 09:25 PM

OK... so I was hoping not to need the help of the great folks on this forum so soon....... but it seems that what started as a hesitation on my new (to me) T-Bird, then progressed to what sounded like a bad coil (intermittently losing a cylinder), is now a nearly dead bike.

When I mentioned the symptoms to my local dealer earlier on I was told it sounded like a fouled plug. Since I've seen plugs just quit I replaced them. Bike seemed better for a very short time then started misbehaving again. Plugs I took out looked ok (6000 miles on them) - but the ones from the 2 outside cylinders were black - center one was grey.... hmmmm.....

To get to the point, A few minutes ago I decided to check out the spark from the coils. Using one of the old plugs and the same plug wire connected to each coil I get the following when I crank the bike :

Cyl 2: snap-snap-snap-snap-snap.....
Cyl 1: snap-........-snap-........-snap...... (seems to be 1/2 the rate of Cyl 2)
Cyl 3: .................................................. ..snap..................

For kicks I swapped the coil for Cyl 2 (the "good" cylinder) with the coil for Cyl 1.... The problem did not move with the coil so am now assuming I'm most likely looking at a bad ignition module.

Anyone have any thoughts on this ? Anything else I should check ? Anything I further can do to validate/disprove my theory other than trying a new module (which I'm going to guess means hauling my bike to the dealer) ?

Thanks,

Steve

[ This message was edited by: ashokanman on 2005-05-29 19:26 ]

trypcil · 05-29-2005, 09:59 PM

Others will have input, but try cleaning the spade end connectors on the low tension side of the coils. Scrape off the oxidation on the coils spades with some wire wool or a small blade and apply a little pressure to the wire end connectors so they clamp better. See if that solves the problem, good luck! :razz:

jimmyj900 · 05-30-2005, 12:26 PM

Replacing the spark plugs and having the bike run OK for a while is a tipoff. A new (sharp edged) plug will fire at a lower voltage than older plugs.

Using the same plug wire to check all three coils was a good move. That eliminates one variable from the testing.

How did the spark look? A fat blue spark is what you want, so if you were getting a skinny yellow spark that's another indicator of low voltage on the coil secondaries.

I'd take a close look at the battery first thing since the igniters and coils can be sensitive to system voltage.

Check the battery fluid levels and top off with distilled water (tap water wrecks batteries) and then charge it fully. Wire brush the terminals and cable ends, grease them, re-connect and see how it runs. If you've got a volt meter check the battery voltage at full charge. It should read 13 volts with 13.2 volts as a no-load theoretical maximum.

The battery voltage will drop with load so you might want to check it with the ignition on and the engine not running. It should read about 12.5 volts and if it drops below twelve you should consider a new battery.

The "snap,snap" testing you did was good and seems to indicate a bad igniter but it's still possible you've got three weak coils. A fraction of a volt difference between the igniter outputs in combination with weak coils can give the same symptoms, so you're not out of the woods yet.

Also, since it's Memorial Day, remember to take a minute of silence at 3:00 p.m.for those who have given all for our freedom. (http://www.remember.gov/)

If it wasn't for them we'd be riding German bikes...

Beemie · 05-30-2005, 07:00 PM

I had a carb problem that I swore was ignition. It was running on 2 cylinders; one pipe was not nearly the temperature of the other 2.
It also didn't move when the coils were swapped.
Carbs cured it and has been fine ever since.

05-30-2005, 09:05 PM

trypcil, Thanks....I checked and there really wasn't/isn't much corrosion - they used conductive grease in the connectors, Not sure if this was done by the factory or a dealer but it works. I polished the connections up some more anyway but it didn't help. I do agree/thank you for your suggesstion on squeezing the connectors to tighten them up though - when I pulled the connectors they were pretty loose - nice and tight now.

beemie, I thought I may have had carb problems as well since the bike sat for a while at a dealer before I picked it up, and it does have some of the dreaded paint peeling around the gas cap that seems to be too common - I even started working on pulling the carbs - but then I saw the erratic spark....

jimmyj900, I owe you one (or two or three). I didn't think about the battery voltage - the headlight was bright and didn't dim significantly when I hit the starter - but I now know that that was/is a big part of the problem.

I hooked up my battery charger, let if charge for a while, hit the starter (with the charger still connected) and it took off on all cylinders. So now I suspect that I may have a faulty battery and/or at least one weak coil (the one that was not firing at all earlier).

Maybe its just the stock coils but I am amazed at how sensitive this ignition is to the battery voltage. The voltage was dropping below 12 V but with every other bike I've had, if there was enough juice in the battery to turn the starter, there was enough for the ignition.

Only thing similar I've seen was when I accidently let the battery in my Yamaha go completely dead (left the headlight on :cry: ) and had no choice except to jump start it. As soon as I pulled the booster cable off after starting it up, it died. Similar to situation this but that battery was completely discharged.

Well... at least I know what's going on now - Thanks to all for for your suggestions/help.

Steve

BTW, jimmyj900, I'm with you regarding Memorial Day - and ask that people also remember the many aging WW II (and other) vets who are still with us. Take a moment to say thank you, help them out, or simply listen to a couple of their stories...

jimmyj900 · 05-31-2005, 02:26 AM

Quote:

Maybe its just the stock coils but I am amazed at how sensitive this ignition is to the battery voltage. The voltage was dropping below 12 V but with every other bike I've had, if there was enough juice in the battery to turn the starter, there was enough for the ignition.

Yeah, a bit of a PITA. The Gill ignitions shut down when the system voltage drops to somewhere between 5 and 8 volts. You might still be able to crank the engine slowly, but the plugs won't fire.

The crankshaft also has to rotate at least one full turn before the ignition can figure out when to fire so you can have significant voltage drop from cranking before it can fire.

That's also one of the things that makes these bikes pretty near impossible to bump start if the battery is down.

The ignition coils are also a bit odd compared to a more traditional Kettering system with ignition points. The Gill coils are more like a pulse transformer in that they don't build and store a magnetic field, so they're also sensitive to the switching voltage.

Lotsa fun.... :-D

Jim

05-31-2005, 06:27 PM

Quick update - T-Bird was in getting it's 6000 mile service today (sure am glad I didn't have to haul it to the dealer). They tested the coil that was producing little to no spark with the low battery and found it was indeed bad. Replaced under warranty....