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996S electrical?

1395 Views 11 Replies 6 Participants Last post by yellow blur, Oct 2, 2009

doublegarage

Discussion Starter · Sep 19, 2009 (Edited)

Hello - my 1st ever post.

I have a 2000 model year 996S. Very low miles and now coming out of bone-dry storage for a new life. The bike was last touched about 6 months ago and started and ran really well.

Battery is one year old and has been on a Battery-Tender and seems fine, certainly cranks the engine just fine. But there is no sign of it even trying to start.

Symptoms:

No buzz from the fuel pump when switching on (should it only do this once or every time you switch on? I can't remember - what are these relays for?)

No click from either relay under the seat when switching on - there is a relay-click from elsewhere - I replaced each under-seat relay with spare and checked the two (5A + 20A) fuses there under the seat - all are good

Took out the sparkplugs after 5 minutes cranking - dry as a bone, a bit black but brushed right off. Held the plug+lead against the top of the vertical cylinder while cranking - no spark seen.

All tubes + wiring under the tank look good, but didn't pull them off to check 100%

So, no clicking, no fuel-pump buzz, no fuel on plugs, no spark - sounds like an electrical problem? I immediately suspected the sidestand interlock - it has the Evolution-overrider. I bypassed that (i.e. removed the unit and plugged the orginal pair together) - no change.

Checked all fuses in the fusebox - all good. Headlamp comes on, neutral light is on - pulled the clutch in, flipped the stand up and down, nothing. Not a single 'bang' ever.

Unplugged and replugged everything in the rubbery relay-bundle behind the battery - no difference.

Could anybody suggest where to go next - I have multimeters (and oscilloscopes!) and know how to use them, just not where.

I've read all the posts here about non-starting and all seem to have either spark/no fuel or no spark/fuel - none with both missing. Any help appreciated - thanks in advance.

-Richard
2000 996S

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bulldog002

· #2 · Sep 19, 2009

Do a search, tons of threads on this topic.

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Shazaam

· #3 · Sep 19, 2009

The pump should cycle on-off each time you power up.

If the ECU fails to detect a running engine during the initial pump run at startup, the pump is then switched off. This is a safety feature, not a function of pressurizing the system initially. If you crash and rupture the tank or fuel lines, fuel would continue to flow with the key still on, over a hot engine - potentially a fire hazard.

A partially plugged fuel filter will cause the pump to draw more current and blow the fuse. The fuse to the fuel pump isn't in the fusebox, it's in an in-line fuse holder underneath the seat.

The fuel lines inside the tank are probably in poor condition on a nine year old bike and the rubber flakes off and pulled into the filter.

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doublegarage

Discussion Starter · #4 · Sep 19, 2009

Shazaam said:
The pump should cycle on-off each time you power up.

Thanks - good to know - it definitely never cycles on at all. Both underseat fuses are good and both have 12volts present when ignition is on.

Shazaam said:
The fuel lines inside the tank are probably in poor condition on a nine year old bike and the rubber flakes off and pulled into the filter.

I agree - they should probably get looked at - but need to find this eletcrical problem first.

Not much else to report - It doesn't seem to be the sidestand switch (in normal operation, the engine doesn't crank with the switch down, does with it up). The kill switch seems to be functioning to some extent (again, engine doesn't crank).

confused...

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94CobraR

· #5 · Sep 19, 2009

Original battery? Change it...

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doublegarage

Discussion Starter · #6 · Sep 20, 2009

94CobraR said:
Original battery? Change it...

No - the battery is less than 1 year old, lives on a battery-tender and has been cranking the bike all day to try and fix it - I don't think it's the battery.

-Richard

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rtzx9r

· #7 · Sep 20, 2009

When you say dry storage, you talking all fluids removed? Could something be too low and not allowing the fuel pump to run?

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doublegarage

Discussion Starter · #8 · Sep 20, 2009

rtzx9r said:
When you say dry storage, you talking all fluids removed? Could something be too low and not allowing the fuel pump to run?

Sorry, no I meant 'in a dry place' with no water anywhere near electricals etc. All fluids are fine, oil was changed about 6 months ago with maybe 20 minutes run time since then.

I guess I'm starting to worry about the ECU - do these ever spontaneously go wrong, like when the bike is parked? My knowledge of electronics would make me think that was highly unlikely, given that it's in a metal-box that's rubber mounted - but I guess it's possible? Are there any diagnostic techniqus for testing it?

-Richard

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doublegarage

Discussion Starter · #9 · Oct 2, 2009

A few days ago I wrote...

doublegarage said:
I guess I'm starting to worry about the ECU - do these ever spontaneously go wrong, like when the bike is parked?
-Richard

To answer my own question, I bought a used ECU and chip from Gotham - and that has fixed the problem. Immediately after switch-on the fuel pump and injectors are heard priming for a few seconds, and the bike starts first crank.

So...yes! the ECU can spontaneously go wrong while the bike is parked. This is pretty surprising to me. About 3 months ago I ran the bike, all was well, switched it off and stored it. 3 months later the ECU wouldn't turn on the fuel pump relay, which also energizes the coils, so no spark either.

I expect there's an output transistor for the relay circuit whose job is to short the relay to ground - the other side of the coil is energised through the kill-switch and safety relay. I'm thinking that transistor has died, which is probably a $0.30 part. So does anybody know where I could find a schematic and maybe a parts list for the ECU (long shot, I know). Of course it could be something else, like the CPU chip in the ECU, but that would have more stuff in the way to protect it.

Why did this happen? - only thing I can think of is that the attached Battery Tender barfed due to a power-surge/lightning strike/gamma ray attack/whatever and fried the transistor. But then, there's a transformer and rectifier in the BT, a 12V lead acid battery (=giant capacitor) across the output, and of course the bike's regulator circuit, so it seems hard to believe, and yet....

Lots of people I asked said "it always looks like the ECU but never is"...and I completely agreed with them, but eventually just ran out of other ideas.

-Richard

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yellow blur

· #10 · Oct 2, 2009

Did you happened to closely examine ALL the connections? Usually just the act of removing and replacing a connector is enough to clean the connection - but only enough to allow contact again. If it’s real dirty it will just be a matter of time before it happens again if not cleaned properly. Sitting, moisture, corrosion…..!

NOT a fan of the Deltran’s Battery Tender -- POS if ya ask me.

I’ve been real happy with the BatteryMinder though… .(no affiliation)

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doublegarage

Discussion Starter · #11 · Oct 2, 2009

yellow blur said:
Did you happened to closely examine ALL the connections?

yes I did, I disconnected the giant ECU connector, brushed it on both sides, sprayed it with contact cleaner, wiped and brushed again and re-connected - no good. I've also replaced the bad ECU once and tried again and it's still bad - which at least proves the harness-side of the connector is not the problem.

I know what you mean about moisture/corrosion while sitting etc, but this is a well sealed connector that looks pristine inside - actually a lot cleaner than the tired looking one I just bought. But that one works...

yellow blur said:
NOT a fan of the Deltran’s Battery Tender -- POS if ya ask me.

yeah I think you're probably right there - I'll look for one of the others.

-Richard

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yellow blur

· #12 · Oct 2, 2009

There is the ground connection at the ECU also that have caused problems in the past - loose, dirty… . The harness also takes a hard bend out of the large connector and can rub on the subframe exposing wire if not attended to, something that may go unnoticed if not at least considered.

I’m not saying it’s something else or not what you replaced, just that there are a lot of connections and possibilities that if disturbed may or may not temporally fix the problem - thinking it’s the part replaced when it was something else only to show up later. Just that it sat and then didn’t work next time --- not that this doesn’t happen all the time. Nice to “SEE” the problem - hard failure point though if possible.

It’s possible moisture got inside the ECU and there is a bad connection/solder point on the circuit board, not necessarily a failed component. Just throwing it out there…thinking too much.....

Glad it’s up and running though! :yeah: Enjoy!!

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