Ignition Problem?

[Blrfl]

I have noticed that the Datel meter will sometimes gain 0.1V momentarily immediately following a misfire event, but it's not consistent.

That's actually not surprising. If the engine sputters, the alternator may sputter with it. The meter's probably not what you'd call lab-grade equipment anyway.

I wish when I'd had the oscilloscope on hand that we had looked at the character of the alternator output.

I have a long list of things for you to look at if you had a 'scope available. If we ever do figure out what's causing this, I'll bet good money it's going to be something very short, and that's how you'll ferret it out.

it's been suggested that if the output looks "hashy" on the scope it could screw with the ECM or be producing interfering RF noise.

You know, that brings up an interesting question from another thread: what's the condition of the resistors in your spark plugs? If the resistance in one has dropped (not their usual failure mode), ignition noise could be making it back up to the ECM.

--Mark

 

[gsforster]

Hey that's a good thought about the alternator. I wonder if it's got a flakey diode or such causing an AC ripple that the ecm does not like at 4250 rpm? Maybe put and AC voltmeter on the battery and run it just for giggles to see if any AC voltage riding along. Disconnect it and try - I'm real curious now.

 

[wjbertrand]

That's actually not surprising. If the engine sputters, the alternator may sputter with it. The meter's probably not what you'd call lab-grade equipment anyway.



I have a long list of things for you to look at if you had a 'scope available. If we ever do figure out what's causing this, I'll bet good money it's going to be something very short, and that's how you'll ferret it out.



You know, that brings up an interesting question from another thread: what's the condition of the resistors in your spark plugs? If the resistance in one has dropped (not their usual failure mode), ignition noise could be making it back up to the ECM.

--Mark

Spark plugs, caps and leads are all brand new.


-Jeff

 

[wjbertrand]

OK, got some motivation from somewhere and I've stripped the bike down to the alternator and I have removed the two top bolts but there is evidently a third bolt underneath that I cannot see. There's no straight shot at it from the front due to the shape of the engine block. Help!! Anyone who has removed an ST1300 alternator, how the hell did you get that third bolt out??

 

[dduelin]

OK, got some motivation from somewhere and I've stripped the bike down to the alternator and I have removed the two top bolts but there is evidently a third bolt underneath that I cannot see. There's no straight shot at it from the front due to the shape of the engine block. Help!! Anyone who has removed an ST1300 alternator, how the hell did you get that third bolt out??

With a long extension. I think I had to use a 3/8" drive breaker-type non-racheting drive to loosen it then used my fingers on the extension to get the bolt out. Put the top two bolts back in snug so the lower one will come out without binding.

 

[wjbertrand]

With a long extension. I think I had to use a 3/8" drive breaker-type non-racheting drive to loosen it then used my fingers on the extension to get the bolt out. Put the top two bolts back in snug so the lower one will come out without binding.

Thanks for the reply, the angle to clear the front of the engine seems to prevent me reaching the bolt. Did you need to use a universal joint or something? Also, anyone know what size socket I need to remove the oil pressure switch? Can't find it in the manual.

 

[dduelin]

I can't remember having to use a u joint but I do have a extension that is a wobble fit that acts like a u joint. I remember it took some patience.

 

[wjbertrand]

I can't remember having to use a u joint but I do have a extension that is a wobble fit that acts like a u joint. I remember it took some patience.

Ok, thanks I'm done for the day (reached my frustration threshold) will give it a go again in the morning. May look into a wobble extension. I was able to get a
1" socket to fit the oil pressure switch. The only 1" one I own had a stupid plastic grip thing around the base that kept it from fitting. Cut that damn thing off and now it fits.


-Jeff

 

[gsforster]

I've had mine out before and I think I ended up using 1/4 drive socket and extension to get that bottom one. As was posted above leave one of the top bolts snug so that once you crack the bottom one it will be an easy go all the way out. I've collected a good amount of wobble extensions at work and they are really good for getting you out of a pickle as well as just making things easier - you won't regret buying a few

 

[Scooter]

I contacted Kevin_56 to find out what he used when he had to remove his alternator to replace a bad O-ring and this was his reply:

We used a socket, extension and u-joint.

Hope this helps...

 

[wjbertrand]

Update: Got the alternator out - whew! I was stymied by the frikin' oil pressure switch which is situated right in the way. Nothing in my tool box would fit it, even my specialized oil pressure switch sensor socket. I went about shopping today and finally found that a 15/16ths 6-point socket fit perfectly. Finally!

I got the alternator out and disassembled the back end and was very quickly able to cross reference a regulator because there was a part number, different to Honda's, stamped right on the underside (126000-1160 for future reference). I figured that Denso would likely not design a specific regulator for the ST and this is proved true. I found the part here for $29.95:

http://store.alternatorparts.com/in254-voltage-regulator-for-denso-alternators.aspx

Among other places, some as cheap as $15! Contrast that with Honda's price of $262.84 (MSRP), and still $186.48 at discount from Partzilla.

The rectifier bridge is more problematic. There's no number on the part itself, though it appears identical to this part:

http://store.alternatorparts.com/inr722p-denso-bridge-rectifier.aspx

$39.95 vs Honda's MSRP of $178.18 or $130.34 from Partzilla again. The rated output of the ST13's alternator is 0.742kW @ 5,000 RPM. Depending whether you use 12 or 14 volts you get between 61A and 53A capacity, so the rectifier at that link should be able to handle the output. What I'm not sure about is whether the amp rating has to be matched precisely or just be high enough to cover the maximum output?

I already have a set of new brushes on hand, the old ones are about 3/4 worn away, so maybe the spring tension holding them to the slip rings has changed to become sympathetic to some engine vibration or something? I cleaned up the slip rings with some very fine wet/dry sand paper and they don't look excessively worn. Bearings seem smooth and quiet too.

I noticed some plastic bits in the "V" of the engine and later noticed they look to have broken off of the rectifier assembly. Don't know if I did that removing the thing or not. Even sitting in the V of the engine, it still takes just the right swear word to get the damn thing out of there once released.

From here, I'll put my home rebuilt alternator back in and give her a test. There's a lot of reassembly involved. The throttle bodies, radiator and t-stat housing all have to come out amongst myriad connector and hoses. I'm going to be challenged to put it all back correctly.

 

[ibike2havefun]

Fingers and toes crossed for you...

 

[wjbertrand]

Got the alternator reassembled tested good and reinstalled, let it sit a day or so then I got brave and thumbed the starter button. Bike started but ran like crap spitting back out the throttle bodies. Noticed an FI light too, so I dropped the side stand and got a "2" MAP sensor error. Sure enough, I'd managed to dislodge the vacuum line to it. Fixed that and it then idled normally. Let it warm up a bit and then did the RPM test. IT STILL F@#$*ING MISFIRES!!!!!


I even tried disconnecting the tachometer on the outside chance the tach itself was the problem. That made it a little difficult to tell what the RPM was but I can almost do it by ear now. Nope, still misfires. At this point I'm putting it up as a parts bike. Make me an offer.

 

[paulcb]

I had high hopes for you Jeff. Sorry it didn't fix it. That's some gremlin you got there!

 

[wjbertrand]

After months of sitting in pieces in the garage, I finally put STat back together. No extra or missing fasteners either - yes I'm that good! The new voltage regulator seems have a bit lower set point than before 13.9 vs. 14.2 V. No big deal. It's amazing how you can rip the electrical heart out of this thing, throw it back together, and it runs as if nothing happened. That's both good and bad I suppose as the glitch is still there. Took it into work today to see if Chris over at Santa Barbara Motorsports is still curious to ride it.

The shame is that other than this glitch, the bike runs really, really well. I synced the starter valves and changed the oil before taking her back out again and I think she appreciates it.

Guess I'll try fitting that Ivan's FCE I have knocking around at some point. Winter is a not a great time to sell a bike so unless I get some kind of offer before then, I'll sell her in the spring. CHEAP.

 

[SteveST1300]

Sorry to hear that you haven't been able to get rid of that glitch.

 

[SupraSabre]

Jeff,

Sorry to hear that you weren't able to fix it.

I don't have the space or the time to play with it, or I would take one of my '04s and start swapping parts until something came up. oh well, good luck.

 

[wjbertrand]

So today I installed a brand new EFI harness and the used engine harness I already had. Bike started right up but..... same problem, engine still misses/hesitates.[emoji20]


Sent from my iPhone using Tapatalk Pro

 

[drtyrrel]

Wow you have a lot of patience. I got nothing for you other than have you tried a new battery?

 

[970mike]

That bike must be possessed!!