OK it's (996) driving me nutz again!

[desmo11]

It's favorite trick now, is to start up great run fine then slowly peter out. All at idle. Seems like it's running out of fuel. Revs up ok and makes good power

Here's what I've tried switching so far:

TPS (set properly too)
Fuel injectors
Water temp sensor (f**king sprayed me with coolant-- none got in my beer though)
RPM pickup (~.026" air gap)
It's got fuel in it
It's synched
Coils sparky-sparky (Technoresearch test via ecu)
Fuel pressure regulator (to 400 kPa no difference)

Tomorrow's menu will include:
Fuel pump
Fuel filter

Bike is running a tad rich for idle perhaps 12.6:1 AFR (I have wideband probes in both cylinders). If the filter and pump don't fix it, I'm going to check myself into the asylum.

The oddball thing I can think of is that b/c I am running 2 injectors per cylinder with a 1 injector cylinder ecu (Marelli 1.6M A0) that the current draw is too much for the ecu's injector drivers. I guess I could test the theory by flashing a 916 ecu map into it and letting it idle. What makes me doubt this is that the bike makes good power. Maybe the only other thing could be the injector dwell time vs voltage being different in the 916 map that I am working from...

[Ben710]

Someone at Ducati.ms had some kind of problem like yours. He checked the pump and the fuel filter, but it was some small clip that got busted at the fuel pump iirc.

[desmo11]

grrrrrr, new fuel pump, new filter, swapped coolant temp sensor.... same shit.

I didn't think it was the pump, injectors, fuel filter, or coils as it works at max power just fine, and in addition the 916 engine ran just fine in it (same pump).

Only a few things left really that I can think to try:
1. New air pressure sensor.
2. Maybe it just wants more fuel. Wouldn't be first bike that wants to be rich at idle. Flash new chip.
3. Decrease rpm pickup air gap, what's the minimum that you guys run?
4. Swap coils
5. New plugs
6. Check closers to make sure they're not loose.
7. Flash single injector chip to check number of injectors theory.

Really starting to lose it with this thing, any help would be appreciated!!!

[john S.]

I can't help, I've lost it on my 916. You have a PM I'm the guy who posted that my cylinders and crankcase are filling up with gas.

[duckracer]

desmo11,
You said you are running the duel injectors on the single injector chip. You may just have way too much fuel and you are "Washing out" the cylinders and spark. We had a race car that had a float level prob and it would run like a striped ape on the top, but would load up and die at idle. It turned out to be flooding so bad that the spark could not ignite the amount of fuel as it loaded up. It would start and idle fine for a bit, then die. run the bike and after it dies pull a plug and see if it's still wet.
I have also seen a pluged up tank vent cause the bike to idle for a bit then as the vacume in the tank got high enough the fuel pump could not overcome the vacume and pull the fuel out of the tank. Usually this will effect top end also, but you never know. We found this when we niticed the tank sides sucking in while running and a loud swoosh when the cap was opened.
Just my two cents hope you get it fixed.

[desmo11]

I've hacked the chip, so fuel has been trimmed accordingly. Also, I have wideband lambda sensors on it and mixture is fine.

Haven't had any issues with a plugged fuel tank vent either.....

I'll try idling with the fuel cap open though... Thanks for the idea!

[Old Baldy]

split fuel lines in tank? Check for fuel swirl.

[desmo11]

Lines were a-ok. Wouldn't make good power if fuel line was split either...

Went in for a masochism session, I mean to work on it tonight....

*sigh* left the wideband lambda systems on yesterday.

Dead battery.

The games will begin again tomorrow....

[jhord]

This is just a crazy thought, but does your map breakpoint start at 0 rpm or something higher? I had a situation once (non-ducati) with a custom ignition unit/map I was using didn't have the breakpoint set low enough, and at idle I guess the rpm variation was enough that it couldn't interpolate what the timing was supposed to be, and it acted all goofy.

Other than that I have no ideas except to set it on fire.

[desmo11]

The idle point is surrounded by map points, lowest is 1000, I could change that I suppose. I'm re-doing some of my wideband equipment, maybe it was off and it's really lean.

Other than that my FAL is starting to speak to me in Italian....

[desmo11]

Ok, zero'd out engine temp corrector and air temp correctors. No change.

Changed baro sensor , no change.

Tried single injector setup, no change.

Found o-ring all screwed up in q/d and changed o-rings within fuel q/d, no change.

Swapped relays and will have another go.

Thing starts up ok, and goes slowly lean until it dies...

[Old Baldy]

Perhaps an electrical ground signal variance somewhere. Is the CPU earth wire intact and bolted down?
All sensor connector pins OK?

Do you have a spare ECU to try...I have one laying around if you want to swap it out for a test...

[desmo11]

Already swapped ecu. No difference.

I need to get a fuel pressure gauge on it and I'll be measuring injector supply voltage, then pulse width on injector switching wire.

Only thing I can think of is fuel pressure is decaying for some reason or electrically things are going to pot.

Also decreased fuel pressure to 300 kPa as that is what it was mapped with.

Don't see any ECU errors when it dies....

[duckracer]

If you start the bike and imedeatly ride it, will it keep running? Will it rev out under load? I think you may have just found it when you said fuel preasure, but check the volume also. good luck. This is one of those nightmare probs!

[desmo11]

Oh, it goes pretty good at the dyno....

Did some 996 tuning yesterday...

but idle is a no-go...

[desmo11]

Gents,

What's normal fuel pump current at key-on?

Seems like my fuel pump wire at the tank side of the connector gets a bit warm.

Key-on voltage at the injector + (same as fuel pump and coil +) goes down to ~11.5V w/fuel pump plugged in and stays at ~12.6V w/o it plugged in.

I don't really hear the fuel pressure regulator squealing much either....

[desmo11]

Well I replaced the fuel pump wiring/fuel level sensor (which was a $160 sodomy).

Looks like that might be it. It idled longer than it ever has. Fuel pressure regulator seems to squeal at key on now too.

The old harness looked like it had a bit of corrosion on the positive terminal at the fuel pump. I'll be damned if that's it... but it seems to run ok now.

Who knows, it'll probably change its mind tomorrow...

[desmo11]

Ok, looks like it's not charging either.

996 3 phase setup on 2 phase bike (916).

Rectifier is off of a Honda VFR800 (Electrex lists it as a cross).

Battery voltage does not go up on rev-up. Max battery voltage is ~12.4V. Constant.

Diode bridge tests ok (rectifier is new Honda part too). Resistance check on stator is ok.

Unregulated output is ~26 VAC @ 2000RPM, and ~77 VAC @ 6000 RPM.

This is a bit down from the Haynes manual specs, I know unregulated output can vary a bit...

Does the unregulated AC voltage sound low to you guys?

[Ducmania]

I seems like your regulator is at fault. I've went through a couple of electrex regulators before I switched to the oem ducati one. Haven't had anymore charging problems. Also you might want to remove the crappy plastic connector from the stator to the regulator (Mine melted). They cause a lot of resistance and fail when you least expect it taking the stator down with them. Simply remove the connector, splice the wires together and solder. Insulate with some shrink wrap and your done.

[desmo11]

Regulator is an OEM Honda one.

I'd kinda be surprised if it were bad....