Was OK, now missfiring above 3k

[robocog]

As per title really,
Been playing with maps and just getting close to being happy as compared to the old mechanical dissy - and literally overnight it has developed a missfire above 3k - fine below - tried different maps - just to make sure I hadn't borked something - and yep checked the rev limit is above 6k so its not that - but does seem similar

Have gone back to old mach dissy and leads - and its OK (so its not fuel or plugs)
Checked the VR sensor is not moving unduly - rpm is shown as steady on the runtime display
so started thinking it was either the coilpack or the leads causing this - a slight push on seemingly any spark lead where it goes into the coilpack seems to rectify this?
We opened out the pins that go into the coil pack (these are new leads - and the coil pack looks new) and also squeezed where they go onto the plugs so the leads are a tight fit

I just thaught today that as the coilpack is only held in by 2 (black coated)bolts and nuts (both of which have shaken loose due to vibration and hurried install) - and wonder if the coilpacks do need a realy good path to earth to operate properly?
(I'm sure I saw a picture of one install where the coilpack was held by ziplock ties) so assumed the coil doesn't need an earth through the bolt holes

Will go out later and nip up the mount I have, and possibly add a braided strap for good measure and will report back

Does the coil pack require a good earth ??


Regards
Rob

________
weed vaporizers

[MartinM]

The bad news is that the coil pack doesn't need an earth at all. On the three pin connector, the centre pin is (ignition switched) +12v and the outer pins are grounded at the appropriate time by the EDIS to cause the sparks.

What engine?
TPS, MAP or neither?
What is the timing, measured with a strobe, at idle with the MJLJ completely disconnected?
Can you get the strobe on it at 3000rpm when it misfires? What does it show?
Open the map file on your PC with Notepad and post the contents in a reply...

[robocog]

OK not so sure now
Just grounded the coilpack and been for a spin round the block
its fine now :-/
Will take it to work tomorrow if weather is kind and put a few miles on it before committing to saying it is now fixed



Using TPS
I laboured for several hours and eventually got it EXACTLY 10 degrees at tickover without MJ plugged in
I even made sure that with MJ in and it saying 16 degrees on runtime display - that is what the strobe showed

Dificult to do the strobe and hold the accelerator at the moment - will wait for missus/victim/voulenteer and will do this (Big Brother on TV - so no chance)

The map I have been mainly playing with is 2D - rev limit is currently set to 7k (so no way engine will get that high)
If I can get the map saved on the works borrowed laptop onto my network I will post it here

Like I say it was working fine for several days - then just wanted to missfire above 3k - and going above trying to get through it didn't cure the missfire

I did manage to chat up the place that I got the coilpack and edis etc from - and they will try and get me another coilpack, lead set and edis to try out
I didn't get the RF suppression capacitor that most of the diagrams seem to show - could it be this?
(though it WAS working fine without before)

Regards
Rob




________
Cheap glass pipes

[robocog]

Made it to work - not even a hint of missfire after properly tightening the coilpack down to the chassis
MartinM - are you sure the coil didn't need grounding at the mounting posts? - if that is true then somehow the gremlins have just gone on holiday
I'm struggling to find any mention of grounding the coilpack on the net
Unfortunately I'm going away at the weekend so no chance of further experiments till next week

Regards
Rob
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Yamaha rd500lc history

[Oliver Sedlacek]

The coilpack doesn't need to be grounded to function, but the Megajolt is quite sensitive to electrical spikes. It could well be that grounding the coilpack reduces these spikes.

[MartinM]

I suppose it could be considered good practice to ground the coilpack and it's interesting to note that the base of it is bare metal, as are the holes for the mounting bolts and the tops of the holes.

Mine is grounded through its mounting bolts but it wasn't a conscious decision to do so.