1 cyl. motorcycle missfiring from in and ex

[garth russ]

maybe i havent searched the forum far enough but heres whats happening. assembled megajolt. had a trigger wheel made and used stock p/u because its inside the engine case and room is very limited. installed edis 4 per diagram using shielded wire 16 awg between p/u coil and edis and also between edis4 and mjlj and grounded per diagram. didnot ground mjljto edis4 pin 4 but to chassis ground. using stock ig coil and resistor plug. alright to the problem- runs fine on edis4. when mjlj is connected, missfiring occurs at idle and real bad after around 3000 to the point the tach is jumping around so much its unreadable. have connected a timing light and its strobe coincides with the missing. have checked for loose connections and found none also the shielde p/u line is routed very close to the plug wire but it rus fine on limp. any ideas?

[brentp]

Try grounding the Megajolt to the same exact point as the ground for the EDIS module. This is important for maintaining a good signal for the 'communications' link between the Megajolt and EDIS module.

What are you seeing in the software when this happens? do the RPMs jump around as well?

[garth russ]

have put both grounds at the same point, now also runs badly on limp, the same as with mjlj. the tach now ocillates between 2 points on the software tach and with the timing light running at the same time,the missing is visible in the strobe. it will still pop out the in and ex now wether in mjlj or limp mode. i have noticed that after trying this that now with the engine warmed good that it is very hard starting. also, timing marks are not visible with the engine running, static only- will have to find a way to remedy this. could i need to replace the stock coil with a coil on plug (ford)?

[brentp]

How stable is the 12V power supply? Can you drag a car battery over to the bike and power up the system separately- just as a test? *very* unusual beahvior!

[garth russ]

tried the 12v auto batt, same result in operating, about 13.09v both batts, missfires idle to about 3000rpm on mjlj, idle to about 4000rpm on limp. both 12v supplies from same source also both grounds. have resoldered all connections on mjlj board to double check. also will check coil connections tomorrow as well as cyl. leak test to verify valves are sealing tight. any other ideas?

[cng1]

There is a fair chance that your trigger wheel either is running slightly eccentric or you need to adjust your crank sensor positioning.

If you are running a single-cylinder engine then I presume that you've left the second output of the EDIS module floating. I am not 100% sure of what the EDIS module behavious is in that circumstance. I think it should work but it might get a bit grumpy.

[garth russ]

have not checked the wheel because its inside the case but will open and check. the edis coil out wire you mention, i had it tied to pin ten, then to pin 12 and it seem to run a little better. i guess the other wire is left disconnected?

[cng1]

I'm a bit confused about how you're driving your single coil. Your coil either needs to be hooked up to pin 10 _or_ pin 12, definitely not both.

In a normal 4-cylinder installation pin 10 fires cylinders 1+4, whilst pin 12 fires 2+3 on the other half of the cycle. So if you have aligned your trigger wheel at 90 deg BTDC on your single cylinder (equivalent to 90BTDC on a cyl 1 of a 4-cylinder engine) then you want it hooked up to pin 10.

[BRUCEROE]

If running a single cylinder on a dual output coil, the other output of the coil must be grounded to complete the plug circuit. Bruce Roe

[garth russ]

yes, i have the coil neg connected to pin 10, runs better than on pin 12 and have taped off the pin 12 wire. did the cyl leak test with air and have between 10-15%, pretty well sealed so that eliminates valve lash. have opened the case, and checking the trigger wheel-p/u coil clearance with a feeler gives .010 inch at every 90 deg turn of the crank. also at tdc, noticed the wheel is missaligned about half of one tooth. can probably correct this with the software right? thanks for all the good advice and if anyone can think of any thing else let me know.

garth

[garth russ]

engine runs much better now. have set trigger wheel alignment at plus 5 deg., it was retarded about 1/2 tooth. have coil neg connected to pin 10. still a bit of popping coming from exhaust, perhaps some carb adjustment will help. software tach much steadier now also. thanks for all the advice.

[garth russ]

still having erradic firing on the mj, runs good and steady on edis. went back thru the testing and verifying and the only thing that doesnt check out is 12v between edis pin 1 (pip) and ground. its about 2v lower than batt voltage. about 3800rpm is where it starts then the controller tach starts to bounce around as does the load gage. i also have a tach on the bike- it has a wire wrapped around the plug wire to pick up the pulse and when the missing occurs, it bounces from about 4000 to 9000rpm. it doesnt seem to work off the mj or the edis directly. im stumped here, could really use some ideas. also, i changed the pip filter to 255 with no change in running.

thanks

[garth russ]

by elimination, the stock coil was incompatible with the ford edis. replaced it with a ford cop and the missing is gone and engine runs flawlessly.

[garth russ]

by elimination, the stock coil was incompatible with the ford edis. replaced it with a ford cop and the missing is gone and engine runs flawlessly.

[NITROPIXIE]

Thats great news garth, it must surely by now ready to put in our powered by section. There aren't too many bikes in this section and it would be great if you could add to it please with a circuit diagram and brief explanation of the setup and the does and don'ts with single cylinder engine

How is the map changing/adjusting going???

Ryan