Need Help. What would you do? Surging and power loss

ScottyG said:
UPDATE! I received the new coils and with great anticipation I installed them but now I'm stuck again and not sure of a next step.

Here's the facts..

1. (1/3) Measured the Primary Resistance of the coil through the 3P connector (yellow/blue) and black wire at (3.4 Ohms) Spec says 2.16 - 3.19ohms (out of spec)

2. (2/4) Measured the Primary Resistance of the coil through the 3P connector (blue/yellow) and black wire at (3.0 Ohms) Within spec from above.

3. (1/3) Measured the Secondary Resistance of the coil through the HT leads without the caps (14.93 Ohms) Spec says 13.5 - 16.5 ohms. Within spec.

4. (2/4) Measured the Secondary Resistance of the coil through the HT leads without the caps (14.53 Ohms) Spec says 13.5 - 16.5 ohms Within spec.

5. (1/3) Measured the Secondary Resistance of the coil through the HT leads with the caps (27.89 Ohms) Spec says 22.5- 25.5 ohms U.S. 22.5-27.5 Intl

6. (2/4) Measured the Secondary Resistance of the coil through the HT leads with the caps (2.27 Ohms) Spec says 22.5-25.5 ohms U.S. 22.25-27.5 Intl

So I had aha moment....the cap on the (2/4) might be bad.......so logically I took a working spark plug cap from the (1/3) side that was working within spec and moved it over to the (2/4) side .......it still measures (2.27 ohms). Hmm...not right....this makes no sense.

SO...I decided to get off the voltmeter stuff look at this from a more basic level. I attached a spark plug and did the "old school" test to see if I can spark by holding the plug in the cap and ground it against the motor. I turned on the power and hit the start button. On the (1/3) side I can see visible spark . On the (2/4) side I am not getting a spark....clearly not good. I made sure to take a spark plug cap from the now good (1/3) side to the (2/4) side...no spark.

I just don't understand why I am not getting the right resistance through from new coil, new HT lead, and a cap from the working side. Or for that matter no spark.

I was very careful to install everything correct an in the same way that the old coils were connected...however there were no markings on the spade lugs of the new coils. Does it matter how the power is connected to each spade lug on the coil itself? This is the two connector that come to the coil from the 3P connector.

Happy Thanksgiving,
Scott
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, Those results on the checking the sparks are exactly the same as mine were, except for being opposite sides. When I tracked down the cause and I found a resistance in that three wire connector, which joins the coils fly leads to the wiring harness, I knew I had got it. I cut the wires either side of the connector, even though it looked OK, and fitted in new individual terminals. I re checked the sparks and I'd got good strong sparks on all cylinders. I started it and it was obviously better. It revved quicker and felt good. Put all the panels back on, road tested and it was all good again. Did a round trip of about a thousand miles, didn't miss a beat. Do that connector, if only to eliminate it. If it doesn't cure it, check the connections on the ecu up front above the headlamp, on the coils and the earth lead connection which is down, close to the foot brake switch(I think). This is unlikely to be it though as it earth's a lot of other things as well as the coils and ecu. Good luck, let us know... Swede.
 
Swede, is the logic to cut out the connector is because it may be preventing something from the main harness going to the coil?
 
ScottyG said:
Swede, is the logic to cut out the connector is because it may be preventing something from the main harness going to the coil?
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Yes. Although mine looked OK, when I checked across mine it was showing a resistance so reducing the power of the coils but not necessarily cutting them out completely... Swede.
 
ScottyG said:
1. (1/3) Measured the Primary Resistance of the coil through the 3P connector (yellow/blue) and black wire at (3.4 Ohms) Spec says 2.16 - 3.19ohms (out of spec)

2. (2/4) Measured the Primary Resistance of the coil through the 3P connector (blue/yellow) and black wire at (3.0 Ohms) Within spec from above.
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One thing to consider when measuring low resistance like this is your multimeter leads can add a few tenths of an ohm to the reading, unless you have a multimeter that allows you to zeroize the resistance reading across the leads, so they don't get added into the measurement. Given that, I'd say your resistance values are more than likely within spec.

ScottyG said:
3. (1/3) Measured the Secondary Resistance of the coil through the HT leads without the caps (14.93 Ohms) Spec says 13.5 - 16.5 ohms. Within spec.

4. (2/4) Measured the Secondary Resistance of the coil through the HT leads without the caps (14.53 Ohms) Spec says 13.5 - 16.5 ohms Within spec.
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this looks good, but the resistances are actually in kΩ, which is what I assumed you measured, but just didn't type it out correctly.

ScottyG said:
5. (1/3) Measured the Secondary Resistance of the coil through the HT leads with the caps (27.89 Ohms) Spec says 22.5- 25.5 ohms U.S. 22.5-27.5 Intl

6. (2/4) Measured the Secondary Resistance of the coil through the HT leads with the caps (2.27 Ohms) Spec says 22.5-25.5 ohms U.S. 22.25-27.5 Intl
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Again, I assume you mean 2.27kΩ, but that is non-sensical because you can't make the resistance go down by adding another component into the path. I don't know how that could happen, so that's a mystery to me, but its something that you need to investigate further.

The measurements with caps uses two caps, so if there is a problem with one of them (or both) and you replaced only one, then you may have not swapped out the bad cap. The fact that the bare coil with wires only is within spec suggests the plug cap is the most likely suspect, but there could be an issue with how the plug cap connects to the wire. You may want to buy new wire for each of the two leads on the strange resistance coil side, it would only cost a few bucks. And make sure you have the plug caps tightly fitted to the wire. Your resistance measurement went up by 13kΩ by adding the two plug caps, but when you measured them before I think they were all in the 5.5kΩ range, so the caps should only have added about 11kΩ. not 13kΩ.

Also, the Honda manual says 22.5-27.5kΩ and doesn't specify geographical location as a qualifier, so I'd use that as your spec.

ScottyG said:
I was very careful to install everything correct an in the same way that the old coils were connected...however there were no markings on the spade lugs of the new coils. Does it matter how the power is connected to each spade lug on the coil itself? This is the two connector that come to the coil from the 3P connector.
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there's no polarity associated with the coil connector, either orientation will work the same.
 
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pretty hard to ascertain a turn to turn short in either primary or secondary windings short of the insulation being totally baked, especially on low impedance wire. if you have continuity and your measured resistances are not bad I'd throw a heat gun at it and see if it changes also examine close for a hair line crack, moisture loves a hairline crack on a coil.
 
even a cheap multi meter you can clean up the probe tips with a fine file or sand paper scuff and use a reading across a scuffed copper pipe or piece of aluminum as a reference point, I wouldn't zero ref my most reliable fluke meter for fat wires. Heat will compress windings and increase leakage current through ____ winding insulation and you'll see it on any $15.00 ohm meter.
 
and dont get discouraged you've probably reached step eight of a nine step problem...
I can hardly wait to see how it ends!!!
It was vacuum! it was vacuum wasnt it!
oh god... tell me I was right,
for just once in my life...
please...
what kind of people are you!!
okay, I'm ready to go back to my room now... can we have jello tonight?
 
Okay gang. UPDATE....

I took Swede's advice and took out the 3P connector in case that was bad. In the process I took out the coil bracket with the coils and noticed one of the spade lugs to powering one of the coils was loose, perhaps I wasn't getting a ground to one side? Alas with high hopes I thought everything was going to work so after making sure all connections were tight I re-installed the coils. I took measurements with my voltmeter and found I'm getting the right resistance through the caps!!

Frustrated that the problem is still there despite all the measurements on the ignition system ( I'm wary now of what these measurements are really telling me). I pulled a spark plug on the 1/3 side and looked for spark....could not see one. Moved that plug to the 2/4 side and I could see spark.....SO my next thought was maybe I should after the caps. I have two on order. Hopefully that will be it....but a least if it does not work I will know that the ignition system is good and can chase down vacuum or other issues that my be suspect......TO BE CONTINUED
 
ScottyG said:
I took Swede's advice and took out the 3P connector in case that was bad. In the process I took out the coil bracket with the coils and noticed one of the spade lugs to powering one of the coils was loose, perhaps I wasn't getting a ground to one side? Alas with high hopes I thought everything was going to work so after making sure all connections were tight I re-installed the coils. I took measurements with my voltmeter and found I'm getting the right resistance through the caps!!

Frustrated that the problem is still there despite all the measurements on the ignition system ( I'm wary now of what these measurements are really telling me). I pulled a spark plug on the 1/3 side and looked for spark....could not see one. Moved that plug to the 2/4 side and I could see spark.....SO my next thought was maybe I should after the caps. I have two on order. Hopefully that will be it....but a least if it does not work I will know that the ignition system is good and can chase down vacuum or other issues that my be suspect......TO BE CONTINUED
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The ignition pulse generator fires cylinders 1/4 and 2/3 at the same time, so the fact that the 2/4 cylinders appear to be getting proper spark would tend to rule out the pulse generator itself. However, there could be a problem in the circuit coming from the ignition control module, so that's still an open item. The blue wire from the ICM goes to 2/4 and the yellow wire to 1/3, so if there's something wrong in the ICM, or the yellow wire path from the ICM to the coil, that could explain why the new coils didn't solve the problem. To diagnose an issue in that part of the system, you'd need a scope that could show the pulses on the blue wire compared to those on the yellow wire. If the yellow looks weak or missing, then that would isolate the issue to the pulse generation side of the fence rather than the coils. But, replacing the coils/caps/wires is cheaper than having it scoped out by someone with the proper equipment, so continuing on the path you're already on isn't that bad an approach cost-wise.

So since you're replacing both caps, replace both wires as well, its an extra few dollars, and after that the only thing left is the ignition control module or the yellow wire path itself.

regarding your being wary of the static measurements, I've mentioned that a few times along the thread. I think those measurements are only useful if you find a shorted or open circuit in the measurements, or something way, way out of spec. I'd also assume that you could have an in-spec static measurement in one of the components, but under dynamic conditions it doesn't work right, so I've been saying all along not to put too much faith in those measurements.
 
Ronn said:
Would not syncing the carbs have revealed a problem with vacuum?

Hi @Ronn, I would normally think yes, but I had a vacuum leak on my ST 1300 that would not show up until the bike was well warmed up (about 30 Minutes). i chased fuel system and electrical for weeks. the problem progressively got worse as the weeks went by and replaced parts piled up. it turned out to be a vacuum line cap/plug that was cracking. after about $150 worth of replacement parts. plug wires, caps, fuel pump and filter, it turned out to be a $0.50 rubber cap on a 3 way vacuum fitting. right now
@ScottyG has better minds than mine helping him!
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You can have the Ecu tested 'off the bike' . Obviously I don't know where there but I do know it can be done, I've had them done here. It's usual that they charge for testing if it's no fault found but if there is a fault the testing is part of the whole job. Might be worth looking into and, while you've got access to the ecu, check the terminals and test the cercuit from ecu to coils for any resistance. .... Swede.
 
I'm waiting to get a ship on the plug caps from PartsZilla, I'm sure they were slowed down over the Thanksgiving weekend. As soon as I get them I will be testing them and posting an update. All I can do it kick the bike when I walk by now....I sure hope I don't have to mess with the ICU or ECU unit. If it is as difficult to get to as the ignition coil I'm not looking forward to it.

Thanks all for "hanging" with me on this.
Scott
 
ScottyG said:
I'm waiting to get a ship on the plug caps from PartsZilla, I'm sure they were slowed down over the Thanksgiving weekend. As soon as I get them I will be testing them and posting an update. All I can do it kick the bike when I walk by now....I sure hope I don't have to mess with the ICU or ECU unit. If it is as difficult to get to as the ignition coil I'm not looking forward to it.

Thanks all for "hanging" with me on this.
Scott
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Surely you can just take the plug caps off, turn it over and see if there's a good spark? Then you'll know if the spark comes back, it's the cap, if it doesn't then the fault is further back.... Swede.
 
ScottyG said:
I'm waiting to get a ship on the plug caps from PartsZilla, I'm sure they were slowed down over the Thanksgiving weekend. As soon as I get them I will be testing them and posting an update. All I can do it kick the bike when I walk by now....I sure hope I don't have to mess with the ICU or ECU unit. If it is as difficult to get to as the ignition coil I'm not looking forward to it.

Thanks all for "hanging" with me on this.
Scott
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Just in case, the ECU is easy to access if it's the same as the st1300, it is located under the seat in the compartment just in front of the tail light. If not the same, someone will jump in with the location.
 
bstig60 said:
Just in case, the ECU is easy to access if it's the same as the st1300, it is located under the seat in the compartment just in front of the tail light. If not the same, someone will jump in with the location.
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Up the front, in the nose, on top of the headlamp.... Swede.
 
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