Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!

1 - 11 of 11 Posts

·
Registered
Joined
·
53 Posts
Discussion Starter · #1 ·
The history:

I've had the bike just a few months and have ridden it a lot (love it).
I had the fairing off to replace the coolant hoses - and rode it with no problems for a few days after that.

Shortly thereafter, it started taking a little longer to start than normal. The last time it started, it took a lot of cranking, then finally started. Then it failed to start one evening after work and I had to load it in the truck.

I replaced the battery (Yausa) - still crank but no start.

I replaced the fuel pump (Bosch), submersible hose, filter, and the big O-ring. Also cleaned the contacts on the fuel level sender.

On reassembly (just now), I still have crank but no start. It will crank for about 10 seconds, then quit. I can hear the fuel pump run when I turn the key on. Twice, the pump made a loud sound (which I assume when it was getting air out) after that it's been very quiet.

I have checked all the fuses in the fuse box on the left side of the dash, and the three fuses under the seat. I have removed both relays, even swapped their positions. Still crank but no start.

The relays are not the same. They are both Hella 4RD, but one is made in USA, the other in China - and they have different part numbers.

I'm good mechanically, but below-average at electrical stuff. I have a multi-meter and I can follow directions.

Any ideas?
 

·
Registered
Joined
·
355 Posts
I always start with fuel and spark. Remove both spark plugs then plug them back into the leads, make sure to ground the threaded portion of the plug, can use length of wire with crocodile clips. Crank over engine and watch for bright regular spark.
Check for fuel by removing air filter, shine torch down throttle bodies , hold throttle wide open and crank over. Should be able to see fuel squirting from injectors.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #3 ·
OK... back to basics. Good idea.

LT Snyder's book said a dirty Crank Position Sensor can cause problems, so I just pulled it and cleaned it. (What a PITA... had to remove a coolant hose to get enough clearance to remove it. It still barely clears... thought I was gonna have to take off the water pump housing to get it out.)

Re-charging the battery now. After all the failed attempts to start it was down to 12.3 volts. Will go test fuel and spark soon. There is a bit more than 2 gallons of fresh fuel in the tank.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #4 ·
I pulled one spark plug, grounded the threads to the frame and cranked. No spark. Put it back in and figured it was safe to look down the wide-open throttle bodies. I did not see or smell gas.

So, we have air, but no fuel or fire.

I'm gonna go inspect/clean/lube electrical connections.

FWIW - I also tried starting with the red key.

I'll be reading up in the book and various threads, but would also appreciate ideas if you guys have any.
 

·
Registered
Joined
·
3,977 Posts
don't use the red key. no point.

check that the fuel pump runs when cranking. if not, it's indicative of a rotation sensor issue. if the pump runs with key on you can assume the rest of the ecu power stuff is ok. no power to the pump means no power at coils or injectors.

it should be about 900 ohms between two of the 3 wires. third is a ground shield.
 

·
Registered
Joined
·
3,943 Posts
As Brad says.
The first "key-on" fuel pump action is merely a 1 or 2 second period that the pump relay is active (commanded by the ECU). The same relay also powers the coils and injectors, as he noted.

When you crank, the rotation sensor provides the ECU with the proper "timing", and at that point, the ECU re-energizes the fuel pump (and coils + injectors) relay. You may not hear it because of the engine noise while cranking. You need to verify that the pump/relay/coils have power WHILE cranking.

Sounds like it's most likely the CPS. Just cleaning it, and re-gappping it does not always cure the problem. Any buddies our UR way to "borrow" a CPS?

A local friend had an extra one, but it proved NOT to be the issue I was having. Mine turned out to be a bad ECU.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #7 ·
I decided to drop it at the dealer. They got it running with a new CPS and 30 minutes of labor - including diagnosis and repair. I have had nothing but positive experiences with Moto Forza in Escondido. Gonna pick it up soon, put the fairing back on... and hopefully get it ride in on Saturday.
 

·
Registered
Joined
·
3,943 Posts
Great to have it fixed! Hey, we were on the right path! It's one component that's not easy to troubleshoot.
 

·
Registered
Joined
·
53 Posts
Discussion Starter · #9 ·
Yup - the Guys at Moto Forza took the time to listen to what I did, and I told them I suspected the sensor had failed.

Not only does it work again, it starts much faster than I have ever experienced - almost instantaneous with the press of the starter button.

So.... to add to the collective wisdom here, maybe there are some warning signs.

Since I've just had the bike a few months, I only noticed that it always took about 2 seconds of cranking to start. But in the days leading up to failure, it would take 4-5 seconds of cranking - and once it "timed out" from cranking but then started on the second attempt.

Hopefully the description of those symptoms will help somebody else.

Had a nice night-canyon ride last night after getting the fairing back on, and rode it to work today. :grin2:
 

·
Registered
Joined
·
6 Posts
Yes it is. Completely new building and stocked with a bunch of nice new bikes. Never heard what the official cause of the fire was. I've been there a couple times since I picked up my ST3 last fall. Seem like nice enough folks. And good to hear that Scud had a good experience there!
 
1 - 11 of 11 Posts
Top