VFR750 1997 rc36 no spark after reg/rec melt-down

[cranston]

Hello, 

 

I have a VFR750 '97 that has had a reg/rec failure. This has been replaced and the melted plug & wiring replaced. 

Now there is no spark at the plugs and the fuel relay/pump doesn't activate which would indicate there is no pulse signal from No 4 coil. 

I've checked the following, and they are all in specification for Ohms and output and continuity:

Ignition pulse generators

Ignition coils x4 

Side-stand switch

Clutch switch

Neutral switch

Continuity between the ICM and the connector ends

4 different ICM units (however, none are "known good") Each produces a signal on the output to the coils

 

Testing the coil output by putting power to the coil and manually earthing the connector produces a feeble spark, but not worse than a new coil.

 

Got to the point of checking astrological charts, mystic tomes, and runes to see if there is anything else that it could be. 

 

Does anyone have the knowledge/experience to cast light on the solution? 

 

 

[Dutchy]

Welcome to VFDR from across the North Sea..

 

 

Kill switch?

(main) fuse?  One may look ok visiually.... measure for continuity.

 

 

Pour yourself a measure of single malt and stop for the day.

Pray to Saint Anthony. 🙂

 

 

 

[cranston]

Thanks Dutchy, 

The bike turns over happily which it wouldn't if the main fuse was dead. The battery is fully charged. 

I'll have a tot of dark spiced rum (or two) and tickle a giraffes nostrils with a feather (I've tried everything else ...)

[Grum]

Have you confirmed battery voltage on the Black/White wire of the Ignition Coils, and that both power and ground to the ICM are good?

 

[cranston]

Hello Grum, 

 

Yep. Battery voltage at the bl/w wire to each coil power to the ICM and earth continuity from ICM earth (solid green) to battery. 

There is output from the pulse generators at the close connector and continuity of output from the pulse coils generator signals to the 16 pin ICM connector. 

 

I'm stumped/flummoxed/bamboozled and bewildered. Sadly I don't have access to an oscilloscope so I can't check the quality of the output from the pulse generators but as it's function is to let the ICM know when to drop the connection to the coil energising the secondary winding -> on to the spark-plug there should be something even if the secondary clutch is 120degrees out ( yes, ultimate straw clutching time ) 

There is nothing at the fuel cut-out relay (the pump runs on a bypass wire) but there is continuity from the No4 coil to the relay. 

Unfortunately I don't have access to a known good ICM  but it is increasingly looking like the fly in the ointment. 

 

Any suggestions gratefully received 

[Grum]

A long shot I guess, but is there any chance your plugs are fouled.

- Have you tried different plugs and have you confirmed the plugs are the correct type?

- Are the high tension leads in good shape?

- Are the two primary connections for each coil making a clean and tight connection?

- Have you tried unplugging the Fuel Cut Relay just to see if this has any effect on spark? Just wondering if there is some fault with this device that may be killing/loading spark output.

- And you have definitely confirmed that the Ground signal from the Neutral Switch is seen at the ICM - Yes? (Essential for Ignition enable.)

 

On a side note. I can't see how the original R/R failure and melted wiring would effect the ICM. UNLESS the R/R had overvolted.

 

Grasping at straws!