'04 RT stick coil secondary-resistance spec?

[MontanaBud]

Is there a secondary side resistance spec for my stick coils? 

 

I checked the "primary resistance" on my stick coils and they are in spec (1k ohms).  However, I get no resistance when checking the secondary side (plug hole + pos connector pin).  Have I found a problem with the coil, or my Fluke, or should there be no resistance as checked?

 

Thanks!

[dirtrider]

9 minutes ago, MontanaBud said:

Is there a secondary side resistance spec for my stick coils? 

 

I checked the "primary resistance" on my stick coils and they are in spec (1k ohms).  However, I get no resistance when checking the secondary side (plug hole + pos connector pin).  Have I found a problem with the coil, or my Fluke, or should there be no resistance as checked?

 

Thanks!

 

Afternoon Bud

 

Basically NO, the secondary is basically isolated with a diode.

 

Not that it really matters as most stick coils fail by internally arcing to the RFI shield & that is not measurable.

 

Try a radio on AM not set on any channel (dead air)--  (remember AM radio?), try different frequency settings. Sometimes an AM radio will pick up the internal arcing. 

 

I worked on a  twin spark a while back  (suspected bad stick coil but couldn't prove). I removed the bolt on the brown ground wire attaching it to the engine (brown wire in the stick coil connector) then held the ground ring about 1/8"  from engine block with engine running & it was sparking lightly (that told me the spark was arcing internally to the RFI shield (not sure this is a valid test in every case but it worked on that one)

[MontanaBud]

That explains that.  Thanks, D.R.!

 

I understand some parts stores can do coil bench testing.  Have you heard of such thing, and might that work?   I tried a spark checker, and there's lighting at idle and a bit above, but that's a blunt instrument that tells nothing of coil operation under load or at higher RPMs.  Any foolproof tests available?

[dirtrider]

13 minutes ago, MontanaBud said:

That explains that.  Thanks, D.R.!

 

I understand some parts stores can do coil bench testing.  Have you heard of such thing, and might that work?   I tried a spark checker, and there's lighting at idle and a bit above, but that's a blunt instrument that tells nothing of coil operation under load or at higher RPMs.  Any foolproof tests available?

 

 

Afternoon Bud

 

It might show something & might not.

 

You can basically do your own test by taking an old (known good) spark plug, then opening the electrode gap to 3/16" (use a 3/16" drill bit as a gap gauge).

 

Then pop that into your stick  coil & lay the spark plug body on the cylinder head, or on engine block, or even use a grounding wire between engine block & spark plug body.

 

Then see if you can run the engine  on the other side stick coil & the lower plugs. If you can keep it running then look at the plug with the 3/16" electrode gap to see if has a bluish colored snappy spark  (if spark real yellow &  weak then possibly a stick coil problem).

 

Another quick test is to remove the lower spark plug wires from the spark plugs, then ground both plug wires so they can't spark open circuit. Then see if the engine will run OK on just the upper spark plugs (it probably won't idle very good though).

 

If it won't run, or one side exhaust pipe is cold, then suspect that side stick coil isn't firing correctly.

[MontanaBud]

I do have spark jumping the gap, but the color blue is barely there.... it's mostly yellow.  Same for both coils, however. 

 

Man this thing idles smoothly!  Just can understand why at highway speeds it runs rough.  More obvious as the engine heats up.  That really makes me suspect bad (or bad-ish) coil(s). 

 

Could it be something upstream from the coils?  Where does this spark come from?  Motronic, hall sensor, ...?

[dirtrider]

14 minutes ago, MontanaBud said:

I do have spark jumping the gap, but the color blue is barely there.... it's mostly yellow.  Same for both coils, however. 

 

Man this thing idles smoothly!  Just can understand why at highway speeds it runs rough.  More obvious as the engine heats up.  That really makes me suspect bad (or bad-ish) coil(s). 

 

Could it be something upstream from the coils?  Where does this spark come from?  Motronic, hall sensor, ...?

 

Evelin Bud

 

The spark actually comes from the coil itself.  The HES tells the Motronic exactly when to trigger the coil to spark.

 

Have you checked the coil (primary) voltage with the engine running? Low coil primary voltage equals low spark. In fact BMW added a 2nd load relief relay to power the upper coils on the later 1150 twin spark engines due to low system voltage going to the upper coils.  

 

As a rule a higher RPM engine disturbance  (above 3500) is not spark related (you might hear a spark related misfire in the exhaust note but pretty difficult to feel it in the chassis at higher RPM's).

 

Can you feel the engine  disturbance sitting still (free-revving the engine in neutral?), if so that is at very little engine load & very small throttle opening so it is basically just free spinning.  

 

 

[MontanaBud]

Thanks, D.R.  It's hard to say after revving it in neutral (or even in gear - danger, danger). 

 

I just took it out for a ride.  Forced it up to 100mph, pulled in the clutch, and the vibes instantly disappear, and in moment, I've slowed to 70mph. 

 

It definitely gets worse as the engine heats up.  At full operating temp, I can feel the vibration throughout the RPM band.  This feels is exactly like when I had a bad coil in the past, and exactly like when I had the bad wiring connection to the rt stick coil (last year was it?).    

 

I put new Beru coils in only 20k miles ago.  

 

I placed a CL ad asking if there are any local RT owners who will lend me a good coil set for testing.  Good bye, Summer!

[MontanaBud]

On 9/2/2019 at 3:44 PM, dirtrider said:

Have you checked the coil (primary) voltage with the engine running? Low coil primary voltage equals low spark. In fact BMW added a 2nd load relief relay to power the upper coils on the later 1150 twin spark engines due to low system voltage going to the upper coils.  

 

Hi DR, can you explain to this dope (me) how to do this test?  Also, where is this 2nd load relief relay, if I have one?

 

Thank you, thank you. 

[dirtrider]

8 minutes ago, MontanaBud said:

 

Hi DR, can you explain to this dope (me) how to do this test?  Also, where is this 2nd load relief relay, if I have one?

 

Thank you, thank you. 

 

Evening  Bud

 

Just use your voltmeter to measure the voltage on the green wire going to the lower spark plug  coil  (needs to be 12v or more).

 

2nd load relief relay is on L/H end of the center row in the under seat fuse box.

[MontanaBud]

I must be doing it wrong.   With the key OFF, the primary leads at each side measures .408v.  With the key ON and while running, the Fluke reads OL.  When testing, I disconnected one lead from the stick coil as I tested that side.   How else?  Help? 

[MontanaBud]

Oh, wait.  LOWER spark plug coil?  The secondary coil under the fuel tank? 

 

BTW, I don't have that 2nd Load Relay in my fuse box. 

[MontanaBud]

 

Sorry, had it grounded improperly.  Each stick coil lead measures 12.5v+ at ON, 13.5v+ at idle. 

 

[AndyS]

Sure sound like a defective stick coil to me.

These normally break down when it is hot or hot and wet.

Have you got someone you know with stick coils that you could borrow  and try the bike again.

[dirtrider]

On ‎9‎/‎5‎/‎2019 at 7:51 PM, MontanaBud said:

 

Sorry, had it grounded improperly.  Each stick coil lead measures 12.5v+ at ON, 13.5v+ at idle. 

 

 

Morning Bud

 

That is excellent stick coil supply voltage, I usually don't see them anywhere near that high unless the bike has the 2nd load relief relay.  I wonder if someone has added a power relay for the stick coils in the past (if added by a past owner the relay could be about anywhere).  

[MontanaBud]

I imagine that would be unlikely.  I got the bike when it had only 3200 miles on it. 

 

UPDATE:  Three days ago I installed a brand new battery, which rendered no change to the vibrations.  Today I received and installed brand new Beru stick coils from EME.  No change. 

 

QUESTION:  I stethoscoped around my idling bike in an attempting to find my vibration source.  One thing that seemed out of order was the noise on the starter motor.  I don't recall hearing any odd sound from there when I checked in the past.  Mostly, it is considerably louder than every other touch point around it.   It also does sound a bit gear-nashing, though not horribly.  Is there something like a "hanging starter" that could be going on and I not know it?  The starter seems to be working completely properly.   New starter installed 4 years and 33k miles ago.  It was a cheap $62 starter from ebay or amazon, I think. 

 

 

 

[dirtrider]

4 hours ago, MontanaBud said:

I imagine that would be unlikely.  I got the bike when it had only 3200 miles on it. 

 

UPDATE:  Three days ago I installed a brand new battery, which rendered no change to the vibrations.  Today I received and installed brand new Beru stick coils from EME.  No change. 

 

QUESTION:  I stethoscoped around my idling bike in an attempting to find my vibration source.  One thing that seemed out of order was the noise on the starter motor.  I don't recall hearing any odd sound from there when I checked in the past.  Mostly, it is considerably louder than every other touch point around it.   It also does sound a bit gear-nashing, though not horribly.  Is there something like a "hanging starter" that could be going on and I not know it?  The starter seems to be working completely properly.   New starter installed 4 years and 33k miles ago.  It was a cheap $62 starter from ebay or amazon, I think. 

 

 

 

 

 

Morning Bud

 

Anything is possible but highly unlikely. Are you sure that the starter to engine  bolts are tight?  (a loose starter could cause your vibration). Is the solenoid tight on the starter? Are the starter through bolts tight?

 

If the starter was staying engaged you would think that it would self destruct being back driven at high engine RPM's.

 

Same with the alternator, anything loose on it's mounting? A loose alternator can REALLY cause a high RPM vibration or buzz.

 

Or might be something in the clutch area telegraphing out from the starter area.

 

These type of things are difficult to find over the internet.

 

 

 

 

 

 

[MontanaBud]

Yes, thanks so much DR.  I did put the scope to the side of the alternator during idle, and it sounded smooth and quiet. 

 

I put a spacer between the center stand rubber bumper and its stop, but no difference found.

 

I've feathered the clutch while driving, and everything seems normal. 

 

I did a leak down test, and both sides were even about 17-18%. 

 

I have another ECM.  Would there be any reason to install it - other than sheer desperation, which is about where I am?  

 

Someone somewhere suggested a possible leak in the fuel pump plumbing.  Could that be causing the vibration, and can it be ruled out with a fuel return volume test?

 

One other anomaly during the stethoscope analysis, the sound from the exhaust pipes (the point most forward, just off the heads) sounds different left to right.  The right side is a bit lower in tone.  Would there be any reason for that? 

[dirtrider]

22 minutes ago, MontanaBud said:

Yes, thanks so much DR.  I did put the scope to the side of the alternator during idle, and it sounded smooth and quiet. 

 

I put a spacer between the center stand rubber bumper and its stop, but no difference found.

 

I've feathered the clutch while driving, and everything seems normal. 

 

I did a leak down test, and both sides were even about 17-18%. 

 

I have another ECM.  Would there be any reason to install it - other than sheer desperation, which is about where I am?  

 

Someone somewhere suggested a possible leak in the fuel pump plumbing.  Could that be causing the vibration, and can it be ruled out with a fuel return volume test?

 

One other anomaly during the stethoscope analysis, the sound from the exhaust pipes (the point most forward, just off the heads) sounds different left to right.  The right side is a bit lower in tone.  Would there be any reason for that? 

 

Afternoon  Bud

 

You can try a Motronic (doubtful to help but if you have the time & energy then try it)___

 

Or measure the fuel flow coming out of the fuel return hose with engine running  (this will bless the fuel pump & internal pressure hoses if it has good fuel return flow).

 

I still feel that at the RPM's you have the disturbance that you are chasing engine/clutch mechanical rather than chasing fueling or spark.

[MontanaBud]

When I free spin the rear wheel (in neutral with a warm to hot final drive, brake caliper removed), I can hear a slight bit of bearing rolling, but also faint click, click, clicking as the wheel revolves.  Ujoint, possibly?  If so, could that create the vibes?  I'm guessing no, since pulling in the clutch at highway speed immediately smooths the vibes.  Also, there seems to be no uneven drag on the wheel, as I had experienced previously, before I replaced the complete driveshaft with an allegedly lightly used unit (under 15k miles) about 4 years and 26k miles ago. 

 

 

[dirtrider]

9 minutes ago, MontanaBud said:

When I free spin the rear wheel (in neutral with a warm to hot final drive, brake caliper removed), I can hear a slight bit of bearing rolling, but also faint click, click, clicking as the wheel revolves.  Ujoint, possibly?  If so, could that create the vibes?  I'm guessing no, since pulling in the clutch at highway speed immediately smooths the vibes.  Also, there seems to be no uneven drag on the wheel, as I had experienced previously, before I replaced the complete driveshaft with an allegedly lightly used unit (under 15k miles) about 4 years and 26k miles ago. 

 

 

 

Afternoon  Bud

 

Maybe, when you declutch & drop engine RPM   that does take the engine out of the vibration (so it seems engine related).

 

BUT, you are also taking the load off the drive shaft so with no load  a wallowed U joint bearing could go back to somewhat self centering & move the joint/shaft  back to closer to running on center. 

 

Try riding the bike to well over the vibration period, then do not pull clutch in but coast back through the vibration period allowing the rear wheel to back-drive the engine (probably won't eliminate a drive shaft/U joint issue  but it might feel different enough to tell something).

 

Also, try riding in/through the vibration zone only use 1 gear lower. That might allow you to define engine RPM effect from vehicle speed effect. (still gives the drive shaft a road load at speed but changes the engine RPM influence to a lower vehicle speed).

 

Difficult to tell you much over the internet without riding the bike but your vibration does sound more mechanical (like a U joint or shaft problem)-- Depends on how engine load is effecting that area).