Fuel Pump Problem Has me baffled?

[dunlop0_1]

Well this is now beyond me. After two days at Oulton Park I am still no better off in fixing this problem on the 996. I spent more time yesterday in the recovery truck LOL.

Set off and all is good then after 5 or 10 mins (sometimes less) the bike will misfire/refire and stop. Then the bike will not start, it turns over fine but the fuel pump doesn't run, sometimes makes an attempt to run but not as it should do. Leave it for a while and it will start and run fine. Completely predictable in it's unpredictability.

I have changed every relay/fuse/sensor/ecu/chip/regulator/pump/filter/coils in fact I think everything there is to change.
Only thing left is the harness? or magic dust.

Neil.

[Jolley]

Do you have a spare pump you can try?.... These are similar problems to when my pump was playing up at Mallory in 2010 (on a 583, but even so). We replaced everything and wiggled every part of loom with engine running.... Eventually cured with new pump (mine had an elec pump on it). Mine would tickover fine and run fine for 5 laps... Then the gremlins would strike.

Or the tank breather?.... Run it with cap left slightly open. It is a long shot.... But just maybe enough of a vacuum could be formed to overpower the pump?

[Chaz]

Neil you can borrow anything you need off my 916 try the complete tank with pump maybe?

[antonye]

I have a spare tank (my trackday tank) you can borrow if you want to eliminate/confirm it's a pump/breather/line problem?

[dunlop0_1]

Thanks guys but I have had two different pumps and press regulators on the bike with no change. All pipes/hoses are clear and intact. :confused:

[antonye]

Is your vent valve fitted the correct way round? Are the vent hoses clear? Is the tank breather (the lines in the tank itself) clear? Are the fuel lines kinking when you replace the tank? Is there a kink in a fuel line futher down to the throttle bodies?

[dunlop0_1]

Yep all clear.
If the harness is a possible issue I was considering this.
The pump has a 12v feed when the ignition is turned on. The ECU then turns the earth on until the pump is up to pressure then turns it off. When the ECU gets a signal from the ignition sensor it turns the earth on again so the engine will run. So if I run a seperate fused/switched live from the battery to the pump and a seperate earth from the pump to the corresponding pin on ECU this in my mind would eliminate any of the existing wiring and possible problem?

[chrisw]

Chafing wire. Had the wire on the fuel pump connector chafing on the top the engine on my 999.

[antonye]

Also try a new fuel pump relay?

[Gbyte666]

I was going to say it sounds like the Pump Neil as I have just replaced mine, I had the same symtons as you. Misfire then ok, then sometimes wont start then nothing wrong at all then finialy packed in all together on a ride out, ( even the mighty Skids did'nt carry one of those with him on a ride out )
But reading down it seems you have replaced the pump ?
Sorry that was not really helpful was it lol
Get the meter out and rattle shake the bike about to see if the readings change drasticaly.

Craig

[Jolley]

Had a loose wire in a connector at Snett last year... Would cut ignition when the bars were turned right. The connector was pushed together ok, but one of the wires could be pulled out of it because the little metal tab on the end of the wire wasn't locked in properly. So maybe try pulling each individual wire out of every connector/fuse/relay/etc... I one pulls out it might be the cause.

[skidlids]

Yep all clear.
If the harness is a possible issue I was considering this.
The pump has a 12v feed when the ignition is turned on. The ECU then turns the earth on until the pump is up to pressure then turns it off. When the ECU gets a signal from the ignition sensor it turns the earth on again so the engine will run.

Somebody rewired it then or is the test meter leads connected wrong as normally the pumps Earth goes directly to earth and the 12 volt feed is supplied by one of the engine management relays with the status of the relay controlled by the ECU, the same relay should also put 12 volts on to the coils at the same time as putting it onto the pump

[dunlop0_1]

Somebody rewired it then or is the test meter leads connected wrong as normally the pumps Earth goes directly to earth and the 12 volt feed is supplied by one of the engine management relays with the status of the relay controlled by the ECU, the same relay should also put 12 volts on to the coils at the same time as putting it onto the pump


Cheers Kev, I actually got that inf from ducati.ms. I've just made a temp harness which runs the pump on it's own. If it works when riding the bike it at least points me towards the wiring albeit from the relay's and or the ecu.

The biggest problem is i have to ride the bike for the problem to occur. Sitting the garage it's fine.

[skidlids]

is it the 1.6M-B ECU and which Chip

[dunlop0_1]

is it the 1.6M-B ECU and which Chip

Yes. I have a DP chip for the exhausts and 2 JHP ones aswell.

[Shazaam!]

The fuel pump supplies fuel under pressure as long as the crankshaft is turning. For safety, the pump is switched off by the ECU after about five seconds if the crankshaft stops turning.

So if the crank rotation sensor gap is incorrect such that it grows too large at temperature, the ECU will think the engine is stopped and shut off the pump. A cracked casing will also cause the gap to be incorrect at temperature.

If the sensor-ECU wiring or the sensor itself is faulty this can also result in pump shut-off.

Check the gap.

[dunlop0_1]

The fuel pump supplies fuel under pressure as long as the crankshaft is turning. For safety, the pump is switched off by the ECU after about five seconds if the crankshaft stops turning.

So if the crank rotation sensor gap is incorrect such that it grows too large at temperature, the ECU will think the engine is stopped and shut off the pump. A cracked casing will also cause the gap to be incorrect at temperature.

If the sensor-ECU wiring or the sensor itself is faulty this can also result in pump shut-off.

Check the gap.

Brilliant. :D

Confirmed somewhat by this guy with the same problem.


http://www.google.co.uk/url?sa=t&rct=j&q=ducati+996+ignition+pickup+gap&source=web&cd=2&ved=0CD0QFjAB&url=http%3A%2F%2Fwww.speedzilla.com%2Fforums%2Fduc ati-superbikes%2F34650-97-853-748-cutting-out.html&ei=3EtFT5HdB8Gq8QON04jBBA&usg=AFQjCNFHaVc6kUCjDSUZgoJOEoOwG7FjXA

[Gbyte666]

Wow, not seen you on here for a long time Shazaam, top tip M8.
Hope that helps Neil.
Dont think I'm going to make Brands as my rear shock is not back from refurb yet. Aiming for Snett to watch your dust. lol

Craig

[bradders]

I may do C1 at Snett too Craig, I like it there :burn:

[dunlop0_1]

Well some progress may have been made. After reading the link posted earlier the guy had exactly the same issues as me. Since I have changed I think every part on the bike I decided to take some resistance readings across the crank sensor and the spare one I used (don't know if it's relevant though). Both of them cold gave around 340 ohms and hot around 450 ohms.
Now compare this with a brand new one which started at around 450 ohms cold and went up to around 980 ohms when hot.
I figure like the guy in the link that the breaking down point of each sensor only kicked in when the bike got to around 180 degrees + hence my first track sessions being with out a problem. Once the sensor had got hot and spit the dummy out I don't think it recovered fully until it cooled again, which possible was not long enough in the 40 mins between sessions.

I'm hoping I had two duff sensors and the new one will prove my right tomorrow at Angelsey. Still taking an ECU wiring harness with me though.

[dunlop0_1]

FIXED :D

Turned out to be a partial break in one of the ECU wires near the multiplug.
Should of been easy to find you may say, the little fecker appears to have been temperature sensitive and old showed its face when either the exhaust made it warm or the poor connection made it warm, expanded and broke the circuit only to cooled then down and make the circuit once more. :mad:

At least I now know all my spares work fine.

Happy days

Well apart form the van which dropped a valve on the way home and is now scrap. :(

[DucSailor26]

Hi there.

Just reading this post and hoping your still around from 2009. I have a 2001 996 Biposta experiencing the same issues. You mentioned that" Turned out to be a partial break in one of the ECU wires near the multiplug."


I'm having the same problem with a temperature sensitive short. Wondering how you went about finding it in the wiring near the ECU multiplug?


Cheers!


DucSailor26