Elecrtical problem!

[mznyc]

Hey guys,I went to put a battery tender on my 02 Scura now that it's finally gotten cold here in the northeast.Without the tender plugged in,the posiitve lead slipped off the battery and touched the ECU at the connector nearest the batt pos post.Looks like the power lead to the battery.It sparked and as I held my breath I tried to start it ,the idiot lights came on then a click and everything went dead.Checked the fuses and the 15 amp that has the headlight icon was blown.Tried replacing it a couple of times and kept doing the same thing.What's your best guess as to what I did?Blow the ECU,a relay,regulator or what.How do I trouble-shoot it.I dont have much knowledge or experience with electrical systems or Guzzis,so dont be afraid to talk sloowly to me.Before this problem there have been no electrical problems.I do have a Ti ECU which I haven't put on yet and didn't want to chance it till I got some feedback from you guys.

Thanks!!,

Michael

[Cliff]

Thats unfortunate.

 

It is very likely that the surge current passed thru the wiring harness and took out the earth wire like a light filament blowing.

 

I think you should try removing the harness covering in a few places and check the wires inside are intact.

[pasotibbs]

I think you should recheck all the fuses (with a mutimeter) as the break could be difficult to see.

Its worth checking the battery terminals for tightness also, if the short was only for a second and directly from the positive terminal to a good ground point you shouldn't have damaged the loom as it takes a second or two to get really hot (the burning plastic smell and smoke usually points to that ).The ECU may not be to happy about it though ,but you should get Ign lights etc even if its deceased.

 

good luck

[guzziownr]

Hi Michael, I did exactly the same thing to my bike and it survived without damage. Give me a ring if you want another set of eyes/hands.

 

Dave

 

guzziownr at yahoo dot com

[mznyc]

Hi Guys,

Haven't been able to investigate further since post.going to look at it this weekend.

some questions though,

pasotibbs-I do have ignition lights,but as soon as I try to start the headlight fuse blows and idiot(me) lights go dead.Don't remember if it happens after I hit the start button or just a few seconds after turning the key on,check it this weekend.The contact was for a fraction of a second,no burning smell or smoke,all terminals were tight.How do I check the fuses with a multi meter,what am I looking for?

Cliff what am I looking for when you say,"check to see if the wires are intact"Do you mean a wire that would have gotten so hot it would actually burn?.And where should I look?

Dave thanks for the offer,but the bikes upstate unless you going up to ski(not far from Belleayre)its a little out of your way.Do want to hook up with you to show me tuneup procedures once I figure this problem out.

Have I stumped Gary,Greg,et all?Lame attempt at male ego psychology .

Thanks,

Michael

[Guest Gary Cheek]

The fact that the fuse does not blow until you try to start points to the circuit(s) energized by the headlight relay as likely suspects. The headlight relay serves to turn off the headlight while energizing the starter and associated circuits. Study the schematic and you should have some good places to look. Study all areas between where you were working and the power SOURCE first. You can put a small light bulb in place of the fuse and watch how brightly it glows. Check the likely spots, disconnect potential loads(LIKE THE ECM ) etc first of all.If by disconnecting a device you find the source of the blown fuses goes away you are real close! For example if the fuse does not blow with the ECM disconnected, the ECM will require board level servicing ( a dying art!) or , the new way-replacement.

It will take a little finger work but most likely you will find some heat-displaced insulation is at fault.

[raz]

Disconnect the ECU completely and check that the rest of the electrical system is OK. My guess is you blew something inside the ECU. Let's hope I'm wrong!

Also, personally I wouldn't be afraid of trying the alternate ECU, but that don't mean you can sue me if you fry it...

[Cliff]

Cliff what am I looking for when you say,"check to see if the wires are intact"Do you mean a wire that would have gotten so hot it would actually burn?.And where should I look?

 

Yes. It could have been a molten mess.

 

The harness is covered in heat shrink or something. I would cut into part of it, being careful not to cut the wires, so as to have a visual on the state of the wires.

[mznyc]

The fact that the fuse does not blow until you try to start say the circuit(s) energized by the headlight relay are likely suspects. The headlight relay serves to turn off the headlight while energizing the starter and associated circuits. Study the schematic and you should have some good places to look. Study all areas between where you were working and the power SOURCE first. You can put a small light bulb in place of the fuse and watch how brightly it glows. Check the likely spots, disconnect potential loads(LIKE THE ECM ) etc first of all. It will take a little finger work but most likely you will find some heat-displaced insulation is at fault.

Hi Gary

How would I check the HL relay.I would assume pull it off,check for continuity or resistence,between posts.If so,which ones and does polarity matter ?

 

Thanks,

Michael

[Guest Gary Cheek]

The easiest test is simple exchange for another. There is actually little the relay could do that would cause a fuse to blow. The relay is low on the suspect list .

 

The relay is basically a switch that is actuated by an electromagnet. The coil terminals should show moderately low resistance The coil terminals should show infinite resistance to the contact terminals. Otherwise there is little the relay could be contributing to your problem due to it's own malfunction.

 

I repeat:

The fact that the fuse does not blow until you try to start says the circuit(s) energized by the headlight relay are likely suspects.

Just so you get off to a logical start by not ignoring the symptoms and the conditions that would bring on those symptoms.

Guesswork is the small part, logical trouble shooting minmizes guesswork.

[dlaing]

From a similar thread, mznyc posted, pointing back to his problem

Just in case anyone who saw this and missed my post,still haven't found anything obvious.Looking for Electrical system diagnostic 101 help.EX"take this probe,put it here and check for this" type advice.

http://www.v11lemans.com/forums/index.php?showtopic=9961

Thanks,Michael!

I really don't have much of a clue on this case.

Everyone gave great advice.

The only thing I might add is that if you don't have great trouble shooting skills, start with the easy stuff like pulling all the fuses and test them for continuity.

Rotate your relays, assuming they are all five pin and not four pin.

Or better yet, buy a complete set of GEI five pin relays from Pyro Dan

Here is a long shot diagnosis:

Make sure you got the correct cables back on the battery and that the polarity is correct.

Your symptoms might indicate a reverse polarity scenario!!!!

Also, check that all the wires that should connect to the battery are connected.

It is easy to let one slip down beside or under the battery.

And don't forget Josh's post,

Guys , this is the second time in the last few weeks that someone has had an arc to there computer when attaching cables to the battery! This is why you should ALWAYS remove the negative battery cable first and when reattaching your cables, attach your positive cable first. This procedure will prevent you from shorting your positive terminal to ground.

If that advice does not help, maybe we could give you some other point by point advice,.

[mznyc]

Hi dlaing,

Thanks for the help and advice.

Nothing is loose.I never loosened any connectors,only attached the battery tender in the correct order but the tender alligator clip slipped off the pos post and touched the ECU power connection that is about and inch from the batt pos terminal.Why Guzzi wouldnt put a .20 Euro rubber boot on the ECU posts to prevent this from happening is beyond me!

I do have the Tl ECU so I'll hold my breath and try putting that on CAREFULLY and see if that is the problem since that was where the contact happened.I planned to try the relays since those are a cheap replacement and seems like a good idea to have some spares.

Obviously something burnt through somewhere in the system that is causing the 15amp Headlight fuse to blow when i try to start.I just don't know how and where to diagnose .There must be a logical order to test ,I just dont have the knowledge of the system to know where to start !

Thanks again,I'll let you know what I find out.

[docc]

Michael,

 

Try pulling the middle relay ,which is activated by the neutral switch, and putting it in place of the headlight relay ( 2nd from the front) and see if she runs. This only works with the side stand down.

 

If so, it's just the relay.

[mznyc]

Hi docc,

Thanks,sounds like an easy check,I'll let you know what I find out.

Michael

[dlaing]

Something else obvious to check is for a loose wire.

Likely culprits in this case would be a dangling wire by the clutch switch or by the starter...Although a shorted alligator clip should not have caused that to happen, maybe a resulting sudden motion by you knocked a wire loose.