Jump to content

97 vfr750 spark mystery.


Recommended Posts

  • Replies 104
  • Created
  • Last Reply
  • Member Contributer
44 minutes ago, Grum said:

Thats a good test Danno. But he has already confirmed all coils generate a spark and all coils have the 12v to them. Its just that #1 Blue/Black wire will not trigger either coil #1 or when placed on #3. Continuity for this wire has also been checked back to the ICM and apparently has no short to frame either!

Just sayin!

Yeah, really weird thing I've come across is that testing individual parts sometimes gives different results than combination. Very odd, can't explain it. Just want to make sure that when fully assembled, power-wiring, coils and trigger-wiring all works without ICM in place. Then any deviant behavior can be attributed only to ICM.

Link to comment
Share on other sites

  • Member Contributer
10 hours ago, Dougwfresh said:

Danno, In the test above do I touch the Alligator clip to the trigger wires or the coils were the trigger wires go?

Trigger wires should be disconnected. So you are simulating trigger-signal from ICM by manually touching earthed wire to coil's trigger terminal (where trigger wires go).

 

Hmm, that doesn't test trigger wires... But you've measured voltage at those wires when coils were powered. So let's assume trigger wires are OK.

Link to comment
Share on other sites

  • Member Contributer
1 hour ago, Dougwfresh said:

Dan, that’s what I did with the lights but non of that would effect ignition.

What did you do with lights?

Link to comment
Share on other sites

I installed a 7” led headlight with turn singles. Which has a head light connecter, 3p and three wires. Left, right, daytime with ground through headlight. I had to cut off blinker and day time connections. I just new connecters and ran the Owire to left turn LB wire to right turn and BR wire to daytime. Combined all grounds G wire. They get there ground from headlight Assembly. Left O/w lb/w br/w wires disconnected.

Link to comment
Share on other sites

 

32 minutes ago, DannoXYZ said:

Trigger wires should be disconnected. So you are simulating trigger-signal from ICM by manually touching earthed wire to coil's trigger terminal (where trigger wires go).

 

Hmm, that doesn't test trigger wires... But you've measured voltage at those wires when coils were powered. So let's assume trigger wires are OK.

What’s the correct test procedure for voltage, trigger wires when coils are powered.

Link to comment
Share on other sites

  • Member Contributer

Hey Doug.

Just counted the number of times I've mentioned a very close inspection of the starter clutch outer, for damaged or bent pulser protrusions.  7 times!

 

After everything you've checked and double checked, coils, HT leads, low tension leads, primary coil voltages, continuity of all wires, harness replacement, two ICM's........Are you thinking it might be time to have a bit of a look see?

 

Sure there may not be anything wrong with it BUT it needs checking and taken out of the equation!

Link to comment
Share on other sites

Do you still feel concerned about the next ICM being damaged?  If you can still perform the 1<>3 wire swap, that means the coil should not be shorting out the ICM #1 spark output.

 

Grum, are you saying if one edge of the 11 clutch protrusions is bad, it won't trigger the pulse generators?   It seems that those protrusions only affect timing and not the whether the trigger works or not.  Does a clean edge make a sharper rise time?   I suppose it wouldn't hurt to check.  Every time I was stumped about anything on my bike, it ALWAYS turned out to be the one thing I didn't check.

Link to comment
Share on other sites

  • Member Contributer
3 hours ago, Dougwfresh said:

 

What’s the correct test procedure for voltage, trigger wires when coils are powered.

sorry ignore that last rambling, you've already tested.

 

Follow earlier procedure where you pull off trigger wires, power up coils and manually trigger spark with your earthed test lead.

Link to comment
Share on other sites

  • Member Contributer
42 minutes ago, eyrwbvfr said:

Grum, are you saying if one edge of the 11 clutch protrusions is bad, it won't trigger the pulse generators?   It seems that those protrusions only affect timing and not the whether the trigger works or not.  Does a clean edge make a sharper rise time?   I suppose it wouldn't hurt to check.  Every time I was stumped about anything on my bike, it ALWAYS turned out to be the one thing I didn't check.

yes, because each cylinder uses different trigger-bump to fire. I'm not familiar with ICM's code or algorithm, but I suspect each cylinder uses these individual bumps to fire:

 

1 = 6

3 = 9
2 = 6
4 = 3

 

Hmm, seems bump #6 being sub-standard would throw off both #1 and #2 cylinders. Best to take off clutch-cover and inspect them all. Or go rent oscilloscope.

Link to comment
Share on other sites

  • Member Contributer
16 hours ago, eyrwbvfr said:

Grum, are you saying if one edge of the 11 clutch protrusions is bad, it won't trigger the pulse generators?   It seems that those protrusions only affect timing and not the whether the trigger works or not. 

Hi eyrwbvfr. The pulses send crank position for each cylinder and rpm to the ICM. So I guess if 1 of 11 protrusions is damaged then the pulses expected by the ICM cannot be correct. How this might effect the spark firing I'm not exactly sure, but it sure will have an effect.

I've mentioned it's kind of grasping at straws but it appears everything else has been checked.

The other doubt is the unknown state of the second hand second ICM!

Link to comment
Share on other sites

2 hours ago, eyrwbvfr said:

Grum, are you saying if one edge of the 11 clutch protrusions is bad, it won't trigger the pulse generators?   It seems that those protrusions only affect timing and not the whether the trigger works or not.

I agree with Danno and Grum. Also because Doug mentions the bike does not start at all, where if there is only one plug not firing it should not be a problem getting the engine to run. So maybe the ICM is sort of confused about crank position and although it does trigger pulses on the other coils the timing may be way off.

Link to comment
Share on other sites

  • Member Contributer

What are chances pulse-generators are reversed? Even though bracket only fit one way, could individual pickup-coils be swapped on those brackets?

Link to comment
Share on other sites

  • Member Contributer
6 hours ago, eyrwbvfr said:

Do you still feel concerned about the next ICM being damaged?  If you can still perform the 1<>3 wire swap, that means the coil should not be shorting out the ICM #1 spark output.

Yes, supposedly there was one combination of parts where swapped triggers for #1 & #3 fired them both. This means both channels were operational at one time. I assume this was with 2nd ICM. Then at some point, that ICM got disabled or damaged and was dead on #1. We have not been able to determine through testing so far what this mechanism is. 

Link to comment
Share on other sites

  • Member Contributer

 

 

19 minutes ago, Dougwfresh said:

No, I’ve never had spark off blue/black tigger wire. I did have spark on coil #1 when red/blue tigger wire was #1  then with blue/black on #3, no spark. 

Ok, I must've have mis-read this post.

 

On 12/31/2020 at 4:13 PM, Dougwfresh said:

Dan, the leads between coil and plugs are new. For instance so on the back right next in front of the  battery there’s the two coils for number one and number three cylinders. number one has the blue with black with the black and white(12v)and number three has red and blue with black and white.(12v) If I take the red and blue and switch it over to coil number one with its black and white cable. I will get spark on coil one and if I hook the black and blue and black to coil number three then I get spark on number three. so it has something to do with the black and blue wire. But it  has continuity between the icu and the coil.

Is power-wire for #3 coil black wire?

 

We'll just test both ICMs with noid-light and go from there. Heck, since it was used ICM, maybe it already had dead channel#1 like yours when it arrived.

 

 

In meantime, take off clutch-cover and have close look at all trigger-bumps on your starter-clutch. And measure clearance to pulse-generators.

Link to comment
Share on other sites

I good multimeter will show pulses in frequency mode (hz).  As long as there is a signal, the details don't matter.  Unless we are now chasing a timing problem.  The fact that its doesn't start eludes to that or compression.  It should run on 3 cylinders, if #1 spark is only issue.  Doug, have you checked timing and compression?

Link to comment
Share on other sites

For compression test, get a tester with different fittings for spark plug threads.  If you never witnessed it running, then anything is suspect.   Any engine timing light will work.  Bad thing about timing (just hit me) is you need to reference cylinder 1!    The inductive clamp goes on the #1 plug lead.

Link to comment
Share on other sites

  • Member Contributer

Amazon UK - compression tester
 

Has all plug-adapters to work with smaller moto plugs. Having bleed valve up by gauge includes volume of hose into combustion-chamber. Will lower readings somewhat. But that's OK, since we're really looking for even readings across all cylinders without too much variation.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy.