Ignition issues 1985 FLTC
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Ignition issues 1985 FLTC
Electrical issues (old school 1985 FLTC). Symptom: Engine will die (tack goes to 0 immediately) either when I put a load on the ignition system (lights, fogs, blinkers) or without a load. Here’s what happens: with the bike idling and warmed up, I can turn headlight (high beam) and fog lights and she idles just fine. However, if I turn either left or right blinker on or hazards, within a 10-20 seconds the tach starts to drop and the engine wants to die, when I release the load she will idle back up. However, I can turn the hazards on only, then load the system with lights, etc and the tach drops and engine wants to die, when I release the load she idles back up. Lastly, I have experienced the same when on the road without lights or blinkers and she will die no matter what speed I’m at (engine dies immediately and tach drops to 0). Here’s where it gets interesting…this only happens after the bike has been running for various lengths of time.
The bike is stock, new factory motor, been running about 1.5 years now and does not have any additional electrical accessories to draw more amps than designed for.
What I’ve confirmed so far: battery is new and fully charged, the stator is putting out 32 volts (new factory lower block allows fit-up for the higher output stator, 1988 and later models), regulator is allowing 14.2~ volts to the battery, battery holds at 13.8~ when loaded. I’ve also confirmed that the module is testing at 1.2 ohms (service manual says 0-1 ohms is good, over 1 ohms replace. I haven’t checked the sensor plate or coil at this time that will be next. Note: I did not use the required HD ohmmeter to test module, however the meter I did use is not a cheaply made one.
Question: Can a regulator put out enough volts but not enough amps? Also, some say that either a module works or it doesn’t. Does this mean it could still function but cause electrical issues or will the bike simple not start?
Who’s got a good thinking cap on?!
Many thanks
Mark
The bike is stock, new factory motor, been running about 1.5 years now and does not have any additional electrical accessories to draw more amps than designed for.
What I’ve confirmed so far: battery is new and fully charged, the stator is putting out 32 volts (new factory lower block allows fit-up for the higher output stator, 1988 and later models), regulator is allowing 14.2~ volts to the battery, battery holds at 13.8~ when loaded. I’ve also confirmed that the module is testing at 1.2 ohms (service manual says 0-1 ohms is good, over 1 ohms replace. I haven’t checked the sensor plate or coil at this time that will be next. Note: I did not use the required HD ohmmeter to test module, however the meter I did use is not a cheaply made one.
Question: Can a regulator put out enough volts but not enough amps? Also, some say that either a module works or it doesn’t. Does this mean it could still function but cause electrical issues or will the bike simple not start?
Who’s got a good thinking cap on?!
Many thanks
Mark
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From: NW AR
RE: Ignition issues 1985 FLTC
Humm, Mark, that's a puzzler. Yes, a module can put out enough voltage but not enough current. Do you have a volt meter on your dash? My 86 does, but I think it was the first year. Otherwise, I'd want to know what the voltage output of the regulator was under load. If you don't have a voltmeter hooked up,I'd hook one up and nylon tie it to the handlebar or some place you can look at it when it is acting up. If the voltage at the battery (and coil) is around 13 when it is acting up, then you probably have a module or pickup issue.
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RE: Ignition issues 1985 FLTC
Thanks for your speedy reply! I'll try your suggestion and see what the reading is. If it looks like I need to replace the module is it a good practice to replace the sensor plate as well?
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RE: Ignition issues 1985 FLTC
It'd be worth a look.....had a buddy that had his scoot settin' up for a year 'cuz it kept dyin' on him. Finally drug it over ta the house, put her on the lift an' got ready ta gut an' rewire it...until ah found a loose terminal on the battery!
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From: NW AR
RE: Ignition issues 1985 FLTC
Yeah, loose or corroded connection could be a problem, as could a broken wire. I had an intermittant ignition system cut out on my bike. Went on for ayear or so. Just every once in a while, it would die, then catch and take off again. It finally died and wouldn't start, 60 miles from home, of course. I had a spare ignition module with me, so I hooked it up. Still no start. At that point, I took my wife's bike home and came back with the truck. One of the wires going to the pickup was broken way underneath, near where it exits the cone. You might try wiggling those wires while it is idling and see what happens, although in your case, if you can make it fail with just a change in the electrical load I would not suspect that.
If you do need a new module, I wouldn't bother replacing the pickup, and vice versa. A stator and regulator I would replace as a set.
So, if you can get this to fail while it is idling, that will make it much easier to diagnose. So, do this:
* Digital volt meter (DVM) negative to engine case.
* DVM Positive to positive on battery. Make fail (turn on lights, turn signals, etc. until motor cuts out). Voltage before and during failing?
* DVM Positive to positive side of ignition coil (the side with the White wires). Make fail. Voltage before and during? Note that the ignition module picks up its +12V at the coil, so it this is low or suspect, that could be your problem. This voltage (+ side of coil) should be real close to your battery voltage. If it isn't then there are multiple connections (potential failure points) between it and the battery. The circuit is: Battery to main breaker to ignition switch to ignition circuit breaker to engine stop switch to + side of coil.
There're more stuff to do, but we're getting into If-Then's, so do the above checks and let's see where we go.
If you do need a new module, I wouldn't bother replacing the pickup, and vice versa. A stator and regulator I would replace as a set.
So, if you can get this to fail while it is idling, that will make it much easier to diagnose. So, do this:
* Digital volt meter (DVM) negative to engine case.
* DVM Positive to positive on battery. Make fail (turn on lights, turn signals, etc. until motor cuts out). Voltage before and during failing?
* DVM Positive to positive side of ignition coil (the side with the White wires). Make fail. Voltage before and during? Note that the ignition module picks up its +12V at the coil, so it this is low or suspect, that could be your problem. This voltage (+ side of coil) should be real close to your battery voltage. If it isn't then there are multiple connections (potential failure points) between it and the battery. The circuit is: Battery to main breaker to ignition switch to ignition circuit breaker to engine stop switch to + side of coil.
There're more stuff to do, but we're getting into If-Then's, so do the above checks and let's see where we go.
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RE: Ignition issues 1985 FLTC
Many thanks! Your service detail is to be commended. If I could buy you a drink I would. I'll test out and keep my fingers crossed.
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RE: Ignition issues 1985 FLTC
Dr. Hess,
Following your serviceprocedures here are the findings:
1. Battery -with DVM negative wire to case and positive wire to battery, voltage before load 14.2 volts; during failing 13~ volts.
2. Coil - with DVM positive wire to positive side of coil (white wire) voltage before load 14.2~ volts; failing (headlights, fogs, hazards) 11.4~ volts.
It would appear that the module is probably bad and should be replaced?
Following your serviceprocedures here are the findings:
1. Battery -with DVM negative wire to case and positive wire to battery, voltage before load 14.2 volts; during failing 13~ volts.
2. Coil - with DVM positive wire to positive side of coil (white wire) voltage before load 14.2~ volts; failing (headlights, fogs, hazards) 11.4~ volts.
It would appear that the module is probably bad and should be replaced?
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From: NW AR
RE: Ignition issues 1985 FLTC
Well, I wouldn't be too sure just yet. When it is failing, you have 13 volts at the battery but only 11.4 volts at the coil, versus 14.2 and 14.2. That is a bit disconcerting. OK, try this: Take a good sized aligator clip, like 14 gauge (not the real thin kind) and hook it to your battery positive. Start the bike. Put the other side to the coil positive. Add the load (lights, etc.) that would make it fail. Does it fail now? If not, then it could be a poor connection between the battery and the main breaker or the main breaker and the ignition switch, or the main breaker itself could be suspect internally. If it still fails hotwired like that, then I would say it was likely the module.
You will have to remove the clip lead between the battery and the coil to stop the bike.
I don't know what shop manual you have. My FLT/FLHT manual is from 1986 and the module/pickup testing is rather sparse, but I also have a 1987 XLH manual that has a thorough testing section for the module and pickup. The Sportster ignition is identical to ours, near as I can tell. The only differences (I think) are the lengths of the wires.
I hate throwing parts at a problem.
You will have to remove the clip lead between the battery and the coil to stop the bike.
I don't know what shop manual you have. My FLT/FLHT manual is from 1986 and the module/pickup testing is rather sparse, but I also have a 1987 XLH manual that has a thorough testing section for the module and pickup. The Sportster ignition is identical to ours, near as I can tell. The only differences (I think) are the lengths of the wires.
I hate throwing parts at a problem.