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Discussion Starter #1
This one boggles my mind, hopefully there is some genius out there to shine some light on it.

I have a 2001 748 with a 996 motor in it. The previous owner did the change and also upgraded the chip. It has done roughly 15,000km with this setup.

Prelude: A few month ago I went for a ride and had 3 hours without any problems. Then the motor started spluttering and stalling. Got it going again and barely reached my destination. After sitting for a few days it didn’t fire up at all. Side note: before the ride I installed a new coolant tank.
A few month later while waiting for a bolt from Ducati (unrelated) the symptoms now are:
Ignition on, both relays under seat switch on, right one turns off after a second, left stays on (I imagine this is the one for the fuel pump?). All good, bike starts and runs. Ignition off and after ten seconds the left relay switches off. After that it does not switch on again with the ignition on. Unplugging one or both relays and put back, no change. Unplugging and swapping over relays, all is good again, bike firs up and runs. Until I switch off for more than 10 seconds again, after that – nothing. I can repeat this as often as I want with the same result. Same with new relays. Also, disconnecting the battery and reconnecting seems to work as well and the bike runs again.
I did all the recommended checks in the forum, fuses, connection cleaning, earth checks, connectivity of wires, checked the fuel pump in and out of the tank, I even replaced the Eprom chip with one that came with the bike (identical to the one installed, got nothing so don’t know if this is a good one), but no luck. It just doesn’t make any sense to me.
I remember “anyoldiron” posted a similar problem 10 month ago and fixed it with an upgraded Eprom. However my setup ran fine for 15,000km but I have no other logical explanation then a failed chip. Can the Eprom get corrupted? Is the fact that I got an identical chip with the bike an indication that it had failed previously and points to a problem corrupting the Eprom after a while? Possible. If this is the case, can the Eprom be “re-set”? I also have two other chips which I assume are for the old 748 motor but I haven't tried them as I don't know much about them.
This problem is way above my pay grade so I’m grateful for any input.

PS: If I’m in need for new Eprom chip, where do I get it in Australia? Also I could not find a replacement waterproof relay as the ones installed in the local auto shops, only normal ones but forum talks about easy to find and very cheap??

Thanks in advance for your help and happy to provide any missing details if needed.
 

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Hi
You could ask Brad Bike Boy from Mel for help. I would suggest you send this detail to him on his email (on his website). He has been super helpful to me while I set my 748 valve timing to his his setting and fitted his eprom for this change. I have since bought a 2nd eprom of him as I now just done an 853 engine mod. Eproms definitely can get corrupted.

cheers
Clive
 

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Discussion Starter #3
Hi
You could ask Brad Bike Boy from Mel for help. I would suggest you send this detail to him on his email (on his website). He has been super helpful to me while I set my 748 valve timing to his his setting and fitted his eprom for this change. I have since bought a 2nd eprom of him as I now just done an 853 engine mod. Eproms definitely can get corrupted.

cheers
Clive
Thanks mate,
I sent an email to Brad last week, just waiting for a reply. I'm trying all avenues because I really want to understand what's happening, and this problem just doesn't make sense.
Why did you change your Eprom? Did you change any engine or exhaust component? So I'm really interested if yours also decided one day not to work properly like mine or you made a change that required a new chip.
 

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My eproms have been fine. 1st one I bought from Brad was to match the valve timing change I did with adjustable pulleys and the 2nd was when I installed 853 pistons. Obviously there are mapping differences compared to the standard 748 eprom.
Hope you get some answers to your problem, let us know what you find.
 

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From the sound of it, you have a failing diode somewhere. Anytime I've had crazy electrical issues they boil down to one of two things. Faulty ground, around 99% of the time. Failing diode that last 1%. Sorry if that's redundant for you, but it's all I got.
 

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check the wiring on the tank (both sides) the start stop switch contacts and the wiring for the start button on the starter relay just off the battery (the sol)

vibration can damage the tank wiring and a battery dangling instead of being removed can damage the other! it may be a case of a wire on its last legs contacting one minuet and not the next!

regards rich
 

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Discussion Starter #7 (Edited)
Faulty ground, around 99% of the time. Failing diode that last 1%.
check the wiring on the tank (both sides) the start stop switch contacts and the wiring for the start button on the starter relay just off the battery (the sol)
Thanks guys,
both sound reasonable problems with Ducati electrics and I had my fare share of them.
I have gone through the wiring first thing and found nothing. Also, it wouldn't make sense to me. The bike wouldn't start up at all with a failed component or only intermittent with a shonky wiring. But whats happening is, I can start it after I do one of the following:
  • change the left relay to a spare relay
  • swapping the two relays over
  • disconnect and reconnect the negative battery terminal (probably works with the positive too)
  • disconnect and reconnect the harness connector to the ECU
  • disconnect and reconnect the 3-wire plug under the seat
What doesn't work:
  • change the right relay to a spare relay
  • disconnect and reconnect the fuses under the seat
  • disconnect and reconnect the main 30amp fuse
  • disconnect and reconnect the two earth wires from thee ECU
  • disconnect and reconnect the same left relay. I have to swap it for another one. I can put it back after I have gone through my one shot with the spare relay.
Again, the bike will run fine after firing up until I switch off and wait for the ECU to boot down (10 seconds) and the left relay disconnects. After that it won't start again unless I repeat one of the things above.
I think it all points to the Eprom. But why it started to play up after 15,000km or how to fix it is a mystery to me.
 

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Discussion Starter #8
Update:

No wiring issues detected but...
After switching off, the Ecu boots down and the Ecu relay disconnects (10 seconds), I can take the relay out and wait for 7-8 seconds, then reinstall the same relay and all is fine. Anything less than 7 seconds doesn't seem to work. That would explain switching to another relay worked because it probably took me more than 7 seconds to do this.

Something is happening in these 7 seconds, I assume it's kind of a re-setting of the Ecu. As I had the same symptoms with a spare Eprom, I do believe it is the Ecu. Any computer experts out there?

PS: Went for a three hour ride, she's running great (but I have a spare relay in my pocket).
 

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I chased a similar problem for months , changed every relay multiple times , new eprom & was debating with a new ecu ..........
Then I went back to basics , R/R had failed , boiled the lead acid battery dry which was at 14v with over 20v being stuffed into it while the engine was running.
Replaced the RR , never had problems since
Just sayin
 
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Discussion Starter #10
Then I went back to basics ,
I'm at this point again, starting all over to check every electrical item. Good idea to also check the R/R, I haven't thought of it as my battery seems to be ok and charging. There is the possibility that some minor fault in the electrical system causes the Ecu to play up. Tedious task but I'm chasing this problem now for only four month.
 

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Discussion Starter #11 (Edited)
Mystery solved!
Thanks everyone for your input. I finally decided to take the bike to a mechanic.

It turned out that it is a faulty ECU. Not much more I could have done here. A simple fix could be to wire a switch in the earth and disconnect each time to re-set the system.

Or has anyone got a spare ECU for a 996 by any chance?
 

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Discussion Starter #15
A bit far to swing past from Sydney. Definitely interested, can you send me a message on 0411150413
 
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