marelli box failing

[bobst2]

i whent for a test ride after checking almost every electrical connection in the bike.the same thing
happened as soon as the marelli box warmed up bike just died.wait 5 mins bike would run but only 2500rpm. wait 1 hour bike runs perfect. i have ordered a new digiplex box & a spare coil & a spare digiplex box.

i hate interrmitiant electrical issues three times on long test rides it died.

[angelix]

could also be a coil , the pickup or sometimes even the fuel pump (when overheats it stops pumping)

are you sure it is electrical?

have you checked the distance between the pickup and the flywheel?

have you tried just warming it up in the garage?

if the problem is electrical it should happen even when is not running on the road.

the fact that happens on the road makes me think it could be fuel related, maybe the pump or dirt in the tank..

[bobst2]

yes checked pump for flow & pressure
cleaned tank screen
filter in carb is new
carb has new jets & needel & seat and has just been cleaned
inline filter is new
all fuel lines are new
checked pick up coil with snap on vantage even when bike is acting up pattern & pulses are fine
when it does it loses spark on both cylenders

via email spoke to ian at italspares he also thought there is a box failing he said that coils very rarely are the issue mostly the box gives trouble
i did order a spare coil though

if you can think of somthing else i should check please advise

[bobst2]

i have had it fail on the hoist while checking the pick up coil

[higgy]

you can't check a pickup coil without an oscilloscope while it is running. You have to check them statically, not the most reliable way But static checks will catch all but heat related failures with 90% accuracy Even with a scope you have to know how to hook it up inductively and know what to look for,very few do,not that its rocket science

[bobst2]

as stated earlier a snap-on vantage testing it was easy gives you the pattern right on the screen has the ability to test pretty much every sensor on the planet.and with my bike useing a single pick up coil hooking it up was simple

[jayh]

My bike did a similar thing with a dodgy connection at the fuse box,I could wobble the wires going in on the brake pedal side and get it going again,just a thought ? Another thing just occurred to me,have you done the ignition upgrade ? A dodgy relay can play up when hot. J.

[bobst2]

thanks j i will recheck the connections in both areas i got the new marelli box & will being installing it after work

[higgy]

the vantage series testers start at 2780 . Basic checks of the electrics to and from the module will find 90 % of what the 3k tester will. And a two dollar squirt bottle of water will find the other 10%

It will do no more for you than a good dvom and checking those connections.
even if your digiplex is bad you need to make sure all the wiring to and from is good before you replace it or you will fry the new one as well.

Don't forget the secondary side,coils,wires and plugs.

I'm not knocking Snap-on testers, Most of what I own is Snap-on, if you have someones 100k baby sitting in front of you,full of can lines and sensors you can't even see then alone get to without removing half an engine it is a wise choice for sure.

For a Paso,its just not needed.

Also, the 3k tester wont know the difference between a failing coil or a bad transistor in the
module. You'll need your brain and the dvom for that

[bobst2]

i agree a good volt meter can do almost everything you need.except data snapshots and scope patterns.
but when you own the equipment it would be dumb not to use it. the prevoius owner ran the bike & messed with it with a bad battery boosting it on a regular basis.
when it failed it lost both coils at the same time. it seems unlikley to me thery are both defective when they get warm at the exact time the bike starts a lot faster with the new box and has a much stronger idle when cold.was unabe to take for a propper test drive as the weather was terrible last night

[bobst2]

well got the bike out for a couple of 10 -15 mile rides seemed ok. will go farther on the weekend.

dident want to walk too far lol

[higgy]

dident want to walk too far lol

been there and done that,but not recently

[bobst2]

well happy to say after several reasonably long rides. the new marelli box did the trick no cut out or backfireing ignition system seems to be fine again. now i have to concentrate on chargeing system perfprmance but that will be a diffrent thread.
thanks for all your help

[bobst2]

well it did it again it ran great for a couple of rides quite a bit further went for a third ride about 15 min,s later did it again runs perfect to 3500 than just a single backfire and quits but will start right back up. but wont rev over 3500 hotter it gets the lower the rpm goes before it quits. it,s getting frustrating

[bobst2]

the wierd thing is it,s not a miss or bad performance it just dies. it has happened right in the middle of a left hand turn in an intersection. or running strait down a smooth road