Loss of power is back. Pulse generator? HELP

crazykz

crazykz

R.I.P. - 2012/06/16
Rest In Peace
Joined
Dec 8, 2004
Messages
1,181
Location
Pewaukee, WI
Bike
2007 ST1300A
Hi All,

Well I thought I may have had bad gas (not me, the bike) or a fuel filter issue but with all of that taken care of (new fuel, heet, injector cleaner, and filter replaced) the problem is back.

I happen to be at the dealer when it happened (that never happens) so I had the tech take it for a ride. While he was out it stopped doing it so he now knows what it feels like when it's doing it and when it isn't. He said it sounded like I was losing two cylinders. It would barely idle at 500 RPM's and there was no power even though you could ride it. Then it just kicks back in and everything is fine.

He said it could be the pulse generator but he's not familiar with the ST (of course). I can bring it in on Monday I guess, which sucks because I have the Bonzai this weekend. Can only give me some ideas on if he's on the right track and maybe I can test some things to see if I can find the issue before Monday.

BTW, I checked to see if it threw any FI codes and there are no codes.

Curt
 
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Curt,

Any chance you are fouling plugs? Maybe too cold a heat range?

I did not go back and read the old thread but since you have basically eliminated fueling, it's got to be spark....Higher heat range plug is a cheap and easy troubleshooting attempt.

Just grasping at straws but it's all I can come up with.

Chris
 
I don't think it's the plugs. They are new and I've run the same range since the beginning. Plus the problem is there and then gone. The coils on the Honda are pretty rock solid although I don't think I can rule it out yet. My guess though is that it's whatever sends the signal to the coil on that side.

Thanks guys. I'm not trying to discourage any ideas but I'm pretty sure this is a more difficult problem than something we can solve here. I'm hoping someone else may have had this issue and can help but I'm guessing I'm going to be in the minority as far as people that have had this issue.

Thanks,
Curt
 
Check the primary wires on the coils. On my old 92 ST1100, I had a primary wire break in the insulation, at the female connector that slips on to the coil. Took a bit of checking but found it. Re crimped a new connector and all was fine. It took out two cylinders. Same type of symptoms. Good luck and let us know what you find.:03biker:
 
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ChucksKLRST said:
Check the primary wires on the coils. on my old 92 ST1100, I had a primary wire break in the insulation, at the female connector that slips on to the coil. Took a bit of checking but fount it. Re crimped a new connector and all was fine. It took out two cylinders. Ame type of symptoms. Good luck and let us know what you find.:03biker:
Click to expand...

Hey Chuck, now I did move that cable this winter and thought I heard it crack. I'm not sure if the coil wire is meant to come out or not but I'm thinking I should check that. It wouldn't surprise me if I goobered it. Not sure how to really check it though. Maybe just wiggle it or something while it's running. I'll probably electrocute myself while I'm doing it though.

I'm not sure if that's it after looking at the manual. Even if I goobered one of the cables that would still leave the other one working and I'm pretty sure I'm losing two cylinders but who knows. Now I do have a pigtail on the coil on that side that feeds to the cruise control. The pigtail is pretty solid though but maybe I should disconnect it and make sure it's not something on the cruise that is doing it. I highly doubt that it is.

Thanks for the suggestion.

Curt
 
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crazykz said:
Hey Chuck, now I did move that cable this winter and thought I heard it crack. I'm not sure if the coil wire is meant to come out or not but I'm thinking I should check that. It wouldn't surprise me if I goobered it. Not sure how to really check it though. Maybe just wiggle it or something while it's running. I'll probably electrocute myself while I'm doing it though.

Thanks for the suggestion.

Curt
Click to expand...
The primary are the two small wires, ground and 12 volt, wires that go to the coil. If they are broke you can feel it. Run your thumb nail very slowly down the wire from the connector. It will usually break right at the crimp of the connector. Also you could do a continuity check with a ohm meter.

Also check that the secondary wire(the Plug wire) is connected good. My money is on the primary side. Hope this helps.
 
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ChucksKLRST said:
The primary are the two small wires, ground and 12 wires that go to the coil. If they are broke you can feel it. Run your thumb nail very slowly down the wire from the connector. It will usually break right at the crimp of the connector. Also you could do a continuity check with a ohm meter.

Also check that the secondary wire(the Plug wire) is connected good. My money is on the secondary side. Hope this helps.
Click to expand...

Yeah it seems like I'm losing two cylinders so I'm not sure it would be a secondary wire but again it doesn't hurt to check them. It's getting to late so it will have to wait until tomorrow.

Thanks,
Curt
 
Chuck, even if you're wrong, that's some pretty insightful analysis. Great post.

John
 
I'm wondering if the 12V is a pulsing 12V then I could put a multimeter on it and if the bike cuts out on that side then I should be able to see a difference on the meter. If I don't then it's probably after the coil.

Thanks,
Curt
 
Hey Curt;
Don't ask me how I know this, but I'd put my money on it being a self inflicted problem. I'm not saying you screwed something up, but I'd check the most recent mods and "adjustments". A critical connection could've been disturbed.

I think I saw my old mechanic using a water mister to locate a pesky firing leak one time. But, I could've been drunk. :capwin: We usually have a few while troubleshooting.

Good luck, keep us posted.
 
crazykz said:
I'm wondering if the 12V is a pulsing 12V then I could put a multimeter on it and if the bike cuts out on that side then I should be able to see a difference on the meter. If I don't then it's probably after the coil.

Thanks,
Curt
Click to expand...

If you are trying to check the primary side of the coil with a dc volt meter I don't think you will see any pulsing as the meter movement is not fast enough to capture it. I think next time I have my panels off I will check and see.
 
crazykz said:
I'm wondering if the 12V is a pulsing 12V then I could put a multimeter on it and if the bike cuts out on that side then I should be able to see a difference on the meter. If I don't then it's probably after the coil.
Click to expand...

You're not likely to get much useful information out of a multimeter on the primary side. Multimeters don't deal with pulse trains very well. (ETA: Yeah, what Chuck said.) The right tool for the job, if you can find someone who has one, is an oscilloscope, which will let you look at the shape, voltage and duration of the pulses going into the coil. A lot of engine analyzers also have probes that will let you look at how the secondary side is doing.

Some auto supply stores have tools for rent; you might check to see if one close to you has an ignition analyzer.

Have you gone through the test procedures in Chapter 20 of the service manual? (Some of it requires a meter that can read peaks. Hopefully your mechanic has done that already.)

--Mark
 
I realize that a multimeter isn't going to measure the pulses but I'm pretty sure I'm going to see some fluctuations on the meter. I've already done this to see if the Ignition Pulse Generator is a least doing something. Granted I can't measure the pulses but I can tell the difference between no pulses and pulses. Now if the pulses aren't correct then I won't be able to tell that but I completely lose that bank so I'm guessing if it is the signal to the coil it will be completely dead when the problem occurs.

I'm hoping it's a loose/corroded connector or a wire issue that I can find when I get the plastic off.

Mike, yes you could easily start pointing at my electrical work but the only thing I have that might affect this issue, I think, is the connector that the cruise control uses off the coil on that side. I can still disconnect all my stuff but I don't think it would affect one bank yet I can't rule it out until I disconnect everything but that's one connector and a couple fuses to do it.

Thanks,
Curt
 
Definite good idea to check the primary wires. I once bought a Honda Civic cheap cause not even the dealer could make it run right. Found the primary wire broken inside the insulation right at the crimp connector.

The problem was intermittent and usually only happened at higher revs. Dealer had replaced all semi-appropriate parts to no effect. Fixed it in 5 minutes after getting it home. Adam totaled it about a month later.
 
I believe what I'm going to do is hook up some small LED's off of the primary(?) side (input side) of the coil. I'll then run then out somewhere that I can see them. When the light will pulse probably at idle but become solid as the RPM's increase. Either way it will be lit when operating normally. Then when the bike does it again the light will either be on or off. If it's on, then it's either the coil or after the coil (i.e secondary wires). If it's off then it's the ECM or something before the ECM.

In the ignition section of the manual it mentions the ignition pulse generator. The fuel section mentions the IPG but also it mentions the cam pulse generator of which there is one for each bank on the bike. Does anyone know what the cam pulse generator does? I may post this question in another thread.

I tore off the left side fairing and check all the connectors on the 1/3 side for the coil. The cruise control works up there and there's a pigtail for it. It's pretty solid though but I cleaned everything and put it all back together. Took me about 30 minutes to take it apart, check everything, run a test, and put it back together. Now I'll ride it at lunch today and see if I can get it to fail again.

Curt
 
Curt,

Do you have an infrared (point & shoot) thermometer or other means of checking high temps? If so take with & ck header pipe temps when failure occurs. That would at least narrow down the problem cylinders.
 
Curt
There is a quick, cheap and easy way to test for the dead cylinder locations. Ground a wire long enough to reach all your primary wires. Connect a small sharp pin (like a large sewing needle) to the other end. You will need to insulate the metal needle from yourself (a pair of pliers with rubber handles works good). While the bike is idling, puncture each of the primary wires to reroute the spark. Done to a good cylinder, the engine will stumble or stall, especially if it is running on 2 cylinders. Applied to a bad cylinder, you won't see any effect on how the engine runs. From there you can determine the location of the faulty ignition component.
My disclaimer: This process works great on a car - I haven't had the need to try it on a bike.
 
Thanks guys. I took it out for a 50 mile spin over lunch but it didn't do it. So either it was a crappy connection or I it just didn't do it. What a pain. I'll look into a spark checker. Might be good to have on the bike anyway. Another thing to add to the 10 pound toolkit. :)

Since the wires are hard, if not impossible, to get to when the fairing is on I wanted to put some indicator lights in that can be seen while I'm riding. I'm thinking up at the top of the tank by the neck. It's shaded there and I should be able to just tape a couple LED's there without too much trouble with wires running back to each coil. If it starts to do it and the LED doesn't go out I'll check the spark.

Someone said that this is a waste spark type circuit and if one plug isn't sparking it might cause the other to not spark. Or if one of the output coil wires was bad and not sparking the plug it might cause the other to not spark also. Anyone have any more info on something like that?

I may have damaged a plug wire this winter while I was moving it out of the way to do the valves. I'll have to inspect it though but I don't think I broke all the cable because that would be just about impossible but it's worth looking at. If one wire can knock out the other then it's worth checking. I'll get a spark checker and get after this thing tonight.

Curt
 
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