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748 / 996 relay or ECU problem or something else entirely?

5914 Views 15 Replies 4 Participants Last post by  Madryan, 
Dragon Tamer
This one boggles my mind, hopefully there is someone 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.

Now 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?). Bike starts and runs, both relays stay on.
Ignition off and after ten seconds the left relay switches off. After that it does not switch on again with the ignition on, therefore no sound from the fuel pump.
Unplugging one or both relays and put back in the same place, no relay action, no pump, no start.
Unplugging and swapping over relays, all is good again, bike fires 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 mentioned in forums: 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 in Ducati MS a similar problem 10 month ago after putting in a 916 engine 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 engine 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 a 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 forums talks about easy to find and very cheap??

Thanks in advance for your help and I’m happy to provide any missing details if needed.
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Shazaam!
The fuel pump is controlled by the engine management computer. When you hit the run switch, the computer powers a relay under the seat that sends power to the fuel pump and turns it on. The computer then checks the crank rotation sensor to see if the engine is running — if not, the computer cuts power to the relay after about five-seconds which then shuts off the pump.

(The fuel pump supplies fuel under pressure as long as the crankshaft is turning, i.e., the pump is switched off by the ECU if the crankshaft stops turning as a safety feature to help avoid fires following an accident.)

Is this initial sequence working correctly?
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Dragon Tamer
Yes, the initial sequence is working when I switch over the two relays under the seat (one for fuel pump, one for ecu). The pump comes on, the bike starts and runs fine. After switching the ignition off I can restart it again in a 10 second period. If I wait longer than 10 seconds, the left relay disconnects. After that I cannot restart it again, both relays do not connect when I switch the ignition on, therefore no fuel pump or ecu input. If I switch over the relays all is good again, start sequence is running ok.
The same happens if I use new relays. I just can't find any logic in it.
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Shazaam!
Dragon Tamer said:
Unplugging one or both relays and put back in the same place, no relay action, no pump, no start.
Unplugging and swapping over relays, all is good again, bike fires 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.
Click to expand...
You may not know that the 1.6M controls it's own power supply. That is, when you turn off the ignition, the ECU stays powered for up to 15 seconds while it does some housekeeping.

Try pulling the harness connector off of the ECU and wait a few seconds, then re-plug it and turn the bike on. Does it start?

Also, it may be worthwhile to try a different battery.
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Dragon Tamer
Yes I'm aware that the ECU stays on, that's the 10 seconds I mentioned, to collect data and stuff like that.

Today I tried your suggestions, I detached and re-attached the harness connector and also used a different battery. Each time I get one shot, meaning the bike springs to life. And as long as the ECU doesn't power down (the 10 seconds) I can switch off and re-start the bike. As soon the ECU powers down and the left relay disconnects, there is no fuel pump going and no start. (Note: Starter motor, lights, dashboard lamps etc. always work)

When it doesn't start I can do one of the following things to be able to start it up again:
  • 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.



How the hell does the bike (ECU) know I put the same relay in or another one?
That's why my logic fails. I can only assume there is still a current going through the relay (but it shouldn't, it's disconnected!) and the ECU registers it and only resets after taking it out. But then it should also work when I put the same relay back in.
Also, if there is any other problem like faulty earth cable or mechanical problem, the bike would not start with a relay swap or reconnect the battery.

What am I missing?
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Shazaam!
I don't know much of anything about the ECU's internal diagnostics and initialization sequence. A Magneti Marelli engineer perhaps might know if your symptoms are a result of an ECU component failure.
There's some smart experienced folks over at Ducati.ms - The Ultimate Ducati Forum so you should trying posting in their Technical Section for advice.

That said, the problem on its surface seems illogical from an external circuitry point of view. That leaves the ECU as the suspect. Perhaps your dealer or a friend has a IAW 16M ECU they'll let you try. You don't need to actually run the bike on the borrowed ECU — just see if the startup sequence works. You won't damage the borrowed ECU/Eprom doing this. Good luck and report back.
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martinl6272
Dragon Tamer said:
PS: If I’m in need for a 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 forums talks about easy to find and very cheap??
Click to expand...
Give Brad Black BikeBoy.org a call or email. He might be able to give you his opinion and may be able to sell you an EPROM.
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Dragon Tamer
Shazaam! said:
I don't know much of anything about the ECU's internal diagnostics and initialization sequence. A Magneti Marelli engineer perhaps might know if your symptoms are a result of an ECU component failure.
There's some smart experienced folks over at Ducati.ms - The Ultimate Ducati Forum so you should trying posting in their Technical Section for advice.

That said, the problem on its surface seems illogical from an external circuitry point of view. That leaves the ECU as the suspect. Perhaps your dealer or a friend has a IAW 59M ECU they'll let you try. You don't need to actually run the bike on the borrowed ECU — just see if the startup sequence works. You won't damage the borrowed ECU/Eprom doing this. Good luck and report back.
Click to expand...
Thanks Shazaam for your replies. I have posted it on Ducati.ms but no bites so far, maybe I should have posted in the technical section rather than under Superbikes.
But you're a top man, always answering to people with ADD (Attention Ducati Deficit).
I will report back once I have found the culprit.
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Dragon Tamer
martinl6272 said:
Give Brad Black BikeBoy.org a call or email. He might be able to give you his opinion and may be able to sell you an EPROM.
Click to expand...
Thanks mate, will follow up. Also closer to home, I'll have a chat to Scott from Duc-Pen, see what I can dig up.
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Dragon Tamer
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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Madryan
I had something similar to this ages ago, mine was just the relay, however I have the tool for extracting engine faults etc.. and noticed mine often comes up with an injector fault code. I do my own engine ( well carb synch, fuel mixture and adjustements tweaking ) but i also use in addition to the ECU tool have a data logger along with Exhaust Gas Temp, O2 sensors and Knock and other matter of sensors hooked up to my own data lagger connected to a SCADA that i made my self, after cleaning my injectors and gettign my fuel mix adjusted to give me even EGT and AFR numbers ive neevr had the issue again. could be a numbe rof flukes but I can assure you havign the right test gear will help you narrow things down, if you were Perth based id be happy to help...I also have spare stock, modified stock and non stck ECU Eproms....I check my throttle body air bypass screws regularly as with my throttla body balance with gauges, the do drift and it doesnt take a lot to make the bike feel...off, mind you mines getn old and tired....

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Dragon Tamer
Madryan said:
I had something similar to this ages ago, mine was just the relay
Click to expand...
Thanks Madryan,

unfortunately Perth is a little bit far from Sydney. I agree it could be a lot of different things, from electrical fault somewhere in the wiring loom (I try to eliminate them one by one) to bad data/settings from the injection system (even the engine seems to run smoothly).

Have you an explanation why I can take out the ecu relay and put it back in after waiting a few seconds to "fix" the problem, meaning to be able to run it again?

BTW, it might get old and tired but your bike surely still looks amazing.
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Madryan
Well, I cant explain that too much, but could be a dirty contact if theyre non guided contacts they tend to not align nicely giving poor surface contact area leading to them burung the gold tips off ( then you have heat , resistance, current doing its magic to destroy your contacts anyway).. I replaced both the relays under my seat with ones from Repco, $14 each and theyve never caused any grief again since dying at the petrol pump. The catch with them is you have to pull the guts out of the Ducati original ones and keep the outer casing and do the same with the repco ones, if you pull the guts out you might find the contacts could be corroded or worn, get a mulitmeter and check the resistance acorss the contacts if its more than .5 ohms(the meter leads resistance)theyre stuffed. I have a lab power supply so can pass high current through relays and solenoids ( starter solenoid for exampel ) to check the contacts for power loss etc... seems like a lot of effort but rules it out. bit like doing a ductor test on a switch board I guess. Theres a guy on Ebay called "Mukeidou" selling a full set of original Ducati relays, if you wanted to have a full set theyre there. however, any old relays with "LUCAS" the prince of darkness should be replaced. the only other thing I can think of with you pulling out and plugging in that relay is a solid state driver on your ECU is giving up the goat for the output that drives your relay. If you have a spare ECU thats the only easy way of checking that one, other wise you need to pass teh max current for teh driever output on your board and measure it while switchign the output and off, but yer getting into teh PCB level component tests here. . However, if you have the ducati ECU tool, you can drive the relay outputs from the software on and off 100 times and see if your relay or ECU output isnt the issue. thats about all the checking I would do before startign to tear apart wiring loom maybe check your ECU main conectors for corroded pins etc... if you pull the large boot off check all the wires are seated in the connector and havent backed out as well. Thats abotu all I can think of off the top of my head.

I am away at work at the moment, if I was Home I would make a video of all these checks and send to you to follow.
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Dragon Tamer
That's already great advice, thanks. I had the relay guts out already and did the 3-step test, and I could visually see what its doing. Also used different relays, I can rule them out. I will check the main ecu connector again, I know I wasn't as thorough last time as I should have been. Lots of food for thought about the ecu. I'll be pretty busy the next week but hope I can get onto it in more detail come August. Then it's onto a diagnostic tool, otherwise I'm going bonkers.
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Dragon Tamer
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 laying around?
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Madryan
You can get the ecu repaired...there's a place that does exchange them but for the price you'd easier buy a used one off ebay...pricing is about 4-500 repair Aud, but for the same price you get a used one ...let me find the link when I'm home and pull out of my internet favourites link I'll send you a PM. Cheers

Sent from my SM-G960F using Tapatalk
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