Backwards Battery smoked ECU Starting Circuit... How to bypass... S2R800

[corey]

Whelp.

I did some muckin' around with the probe-o-meter.  

• Checked STARTER BUTTON (hand controls) at ECU Pin #28. Upon pushing the button, resistance drops to ~ 0.04 ohms  

• Checked STARTER SOLENOID at plug/socket leading into the solenoid itself. Resistance clocks in at 4.3 ohms...  

• Checked the DIODE at the solenoid connector going into the loom with my positive lead on the Red/Black side of the plug and my negative lead on the other side... it came it at 710 milli-volts, which unfortunately clocks in damn close to 0.6v... probably fine. Out of curiosity, i cut the sheathing off the loom all the way back to the diode just visually inspect it, and the wiring around it. All looks fine to me... Obviously I'm no pro.

• Checked for continuity between Pin #1 in the ECU and and the Red/Black side of the Solenoid Connector. It's fine.  

• Checked for continuity between the other side of the connector and the Battery VE+... No continuity here... Is this significant? Or should i NOT have continuity.  


After all this, I was obviously discouraged. Three strikes. No solution.
I thought back to when my battery used to die... You know, when I would leave my lights on while we ate breakfast at Bob Evans...
When I would push my start button, I could clearly see the headlight dim and/or shut off momentarily. I'm working with a brand new battery here, which I even put on a tender after a couple wrench-gap-bridging starts last time around just to be safe. I notice now that with FULL power going to the headlight â€" i mean as bright as it's ever been â€" when i push that start button, no flicker at all. just solid light. Throw another stone at the starting circuit in the ECU.  

I figure at this point, what the hell, let's try bypassing the ECU. Rather than mucking with the plug â€" and because I wanted to make sure I had enough wiring to piece things back together once I replace the ECU down the line, likely with a DP flashed unit â€" I found a section of the loom slightly forward of the ecu with easy access. I sliced into the sheathing, finding a multitude of wires that for some reason weren't so intimidating anymore (desperation setting in). Orange/Red? SNIP. Red/Black? SNIP. Twist together.... Check...

Turn key... Gauges sweep... fuel pump primes... lights are on... start button in... Vrooom. Fired right up.  
Shut her down and did it again too. Fired right up.
Third time not so lucky, ran out of juice i think. I had started it up a couple times earlier with a wrench as well during testing, just to make sure i didn't break any connections after the solenoid.
The starts are a little hard because my air-gap on my timing sensor is still off (need to sand the shim down a little more).

At this point, it's obvious that the issue is between where I cut the starter button wire, and where i cut the solenoid wire. Only culprit in that region is the ECU.

Obviously the REAL culprit is me being an idiot.

Based on my description of my experience above, can anyone think of any other possible explanation?

Like I said in the beginning.. I think i really botched this one up proper.

So i guess if we move on from here, is there any other possible damage i could have done that will... i dunno.. drain the battery or shit like that?

Is there any negative effect of running the bike this way permanently? Or should I save up for a new ECU and get my wiring back into factory order?

[Howie]

Only two negatives I can think of, 1. you are bypassing the sidestand and clutch safety switch.  Negative?  Up to you.  2.  If your quality the snip and splice is not so hot there may be a failure down the line.

[suzyj]

Actually I don't think he is completely bypassing the clutch and sidestand switches, as these are wired separately into the ECU.

If the stand is down and it's in gear with the clutch out, the starter will fire but it won't start.

[take risks]

The level of this conversation confirms that I have a long way to go.



Good luck.

[Howie]

Actually I don't think he is completely bypassing the clutch and sidestand switches, as these are wired separately into the ECU.

If the stand is down and it's in gear with the clutch out, the starter will fire but it won't start.

So, the bike will crank but not run?  Makes sense.  I guess we will know for sure shortly.  We are waiting, Corey!

[corey]

actually, this is one of the things i checked last night, because I too was curious/concerned.
i didn't try starting it with the bike in gear and clutch out... it's on the stands still, so i didn't want it to "buck" itself off.
i did start the bike in neutral. kickstand down in neutral, still runs... this is normal.
then i pulled the clutch in and kicked it down to first with the kickstand still down. shut right off as it normally would.
seems like the only single thing to get bypassed is that headlight dimmer... which i imagine that if i have a good, functioning charging system (pretty sure i'm in the clear here... just had the side covers off and the stator was in beautiful shape), i should be fine without.

regarding my splice:
I stripped back about .5in on each wire, split each wire end into two, and intertwined them... then followed up with what i consider a "function over form" soldering job. it's not the prettiest soldering, but if that make the beast with two backser comes apart, then i'm just not meant to ride this bike this year. did i nice wrap with 3M super 88 electrical tape (only the best will do!), and will be following that up with some heat-shrink tubing shortly. I also clearly marked the other two ends of each wire with a piece of blue heat-shrink in case I need to revert back (when I'm able to save up enough for that new DP ECU).

also, i realized that i DID not have my battery on the tender before last night, so that batter had probably 10 or so cold starts on it with a wrench over the solenoid... that sound like it could kill a battery?

@take risks:
believe me man, i thought the same thing when i started to think "ecu problem"
if it wasn't for some top notch help and guidance from this board, i'd be boned for sure.
never in my life did i imagine i'd be cutting into the wiring harness of my $10,000 bike to bypass the ECU in my own garage.
i can't figure out how the hell people even owned vehicles before the internet.

i think my biggest worry right now is that i fried some other important circuit in the ECU... possibility?

[suzyj]

i think my biggest worry right now is that i fried some other important circuit in the ECU... possibility?

Naah.  The only other things that the ECU drives that have any current capability (and hence the ability to blow to a frazzle) are the relays, coils, and injectors.  The bike just won't run if it's not driving them.

I'm just really happy we were able to help you out - you caught me at a good point, where I have my loom in a thousand bits spread right around the house...

[corey]

Suzyj i can't thank you enough. You basically handed me a turn-by-turn on how to solve this issue. It certainly blows big time that I made this mistake, but I did learn a lot. My confidence with electrical problems has increased greatly. It's really not that complex once you dive in.

Regarding other possible problems:
Essentially, if I had the bike running for about 10 minutes or so, would you say that I'm in the clear? Or should I do some testing on any other relays, the coils, or the injectors?

[corey]

Follow up three days later...

After giving the new battery a full charge from my Optimator, as well as sanding down the timing shim to "close enough"... All seems well in this world.

I will say that there are a few intricacies that I'm going to have to get used to â€" and be careful about â€" regarding the starting protocol.

While the bike still will not start with the kill switch engaged as normal, it WILL crank. So if I have the kill switch in the OFF position, and don't notice, the bike will crank and crank and crank and crank.

Same thing goes for the kickstand and being in gear.

The bike will shut off if I put the kickstand down while in gear as well. This is good.

However, the bike WILL start while in gear with the kickstand up... It likely wouldn't do so while on the ground, but I have yet to test that. But on the stands, with NO weight on the rear wheel... the bike started and the wheel started turning...

Basically, it's like an old ducati now. Hah.

I'm not to worried, as I'm pretty religious about front brake and clutch when starting, so I should be fine.

The last thing I did notice, that I can't imagine is TOO big of a deal, is that the starter will crank with the bike running if I push the start button... I don't recall ever trying that before, but i'm not really too excited about that prospect. Could it possibly hurt anything? I mean, i don't go around pressing that start button with the bike already on, but just curious if it could screw anything up.

I was planning on going open air box and DP ecu flash next winter, So i guess I'll just have to add a few hundred extra bucks into the pot for a complete ECU with no core exchange...

[corey]

Calling Suzy...

One last question. Is there a good chance of this ECU shitting the bed on me now that it has a fried circuit?
I know we discussed some of the other parts that were at risk, but were any of the other circuits in the ECU vulnerable to damage when the battery was in improperly?

I have some long rides planned this year, and I'd hate to have a problem on the road...

[suzyj]

Calling Suzy...

One last question. Is there a good chance of this ECU shitting the bed on me now that it has a fried circuit?
I know we discussed some of the other parts that were at risk, but were any of the other circuits in the ECU vulnerable to damage when the battery was in improperly?

I have some long rides planned this year, and I'd hate to have a problem on the road...

No, the damage that's done is done.  Truth be told, everything should have survived a reversed battery, with the exception of fuses.  It's one of the tests that automotive electronics are regularly put to during design.

If you have a look at the S4R owner's manual (I've been downloading as many different wiring diagrams as possible), you'll note the ECU connectors are labelled.  The pin that drives the starter solenoid is labelled "O2HEAT2".  My hypothesis is that Magneti Marelli had no intention of driving a starter solenoid directly with their ECU, so made no provision (bear in mind that the ECU is common to a whole pile of vehicles, and not just bikes).

So when Ducati wanted something to drive a starter solenoid, and were too tight to add a 50c relay, some smartarse said "hey, let's use the second O2 sensor heater driver for that", so they tried it, and it occasionally blew up from the back-emf of the solenoid coil, so then they added the diode (in the loom? - WTF!), so yeah, you end up with a circuit that's not really terribly well designed.

And whereas everything else in the bike is carefully protected against reverse battery, this bit...  Not so much.

So in summary, this is almost definitely the only damage to your ECU.

[ungeheuer]

This thread right here is why I love our DMF so effing much 

Absobloodylutely awesome suzyj 

(Especially for a Magpies supporter  ).

[WhiteStripe]

i can't figure out how the hell people even owned vehicles before the internet.

Amen.

Hope this works out for you.

[Speeddog]

i can't figure out how the hell people even owned vehicles before the internet.

The guys behind the parts counters knew a lot more than just how to fetch a box from a bin.

[DarkMonster620]

Corey, could you post pics?