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Discussion Starter #1
Hi All
Can someone assist me I have a 2003 F4 750 I have just replaced the following battery, fuel pump and hoses.
Now it won’t start, it looks like I have no fuel at the injectors, should there be voltage at the injector with the ignition on?.
Or what else could I destroyed in the repair process
R
Petermac
 

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@Peter Mac: First let me welcome you to the world of MVAGUSTA.NET!

There are several reasons that your bike may not run now. The two most prevalent are reversed polarity battery and not reattaching all of the wires that were originally present before battery replacement.

So, a couple of question to get started: Was the bike running just fine and unmodified prior to battery installation? Is the NEGATIVE terminal on your battery facing the FRONT of the bike? Do you have the Shop Manual for your bike so you can see the wiring diagram?
 

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475672
 

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Wow...member for 10 years and just now saying hello !! Welcome to the family.

What Chuck said above.... and Yes, there should be 12 v at each injector when the key is on. The ECU makes and breaks the ground circuit to fire the injectors. Same thing with the ignition coils.
 

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Discussion Starter #5
Hi All
Yes the battery is connected correctly, if I squirt a little fuel down the throttle body the engine fires.
I don’t believe I have power at the injectors.
 

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Easy to check with a volt/ohmmeter.... Does the fuel pump prime? Perhaps your pump and hose replacement is the source of your no-start? Hose popped off on the pump when you filled the empty filter on first prime? That has happened to me before.
 

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How are you measuring voltage?
 

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Discussion Starter #9
The pump is priming for about 3 seconds then stops, it then starts when cranking over the engine so don’t think it’s a loose hose, but will check again.
I don’t have a multi meter, so I used a series light to test for power.
 

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The hose has nothing to do with the 3 seconds. That is an ECU program.
 

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Could be your fuel tank connectors not letting fuel through.Take a hose off the injector rail into a container and switch the ignition on.Is there fuel squirting out?
 

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Discussion Starter #12
Ok thanks all I will re do all of the above and get back to you, thanks it’s a great re start as this has been doing my head in ?
 

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I've noticed that some of my Gen-1 injectors are starting to get a little worse for wear (several of the multiple port holes becoming clogged. I'm replacing the ones on the 910r but it may be worth checking them and a service?
 

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You replaced the hoses? Maybe not enough fuel being primed. Prime it 3 times before starting it.
Turn ignition to "on", let it prime for 3secs, turn it off,
Turn ignition to "on", let it prime for 3secs, turn it off,
Turn ignition to "on", let it prime for 3secs, turn it off,

Than turn ignition back to "on" and try starting the bike.

Otherwise @cruiser might be on to something, clean or replace the injectors.
 

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Discussion Starter #15
Ok thanks all I will re do all of the above and get back to you, thanks it’s a great re start as this has been doing my head in ?
I have done all the above and still no love, is it possible the ecu has died? Is there any other checks I can do.
I haven’t removed the fuel injectors how likely is it that all 4 are failing
Is there a plug or fuse I’m not aware of..
 

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@Peter Mac: You need a systematic approach to what you are checking. The shop manuals will provide that and they are available at no charge here: MV Agusta Team Double 3 Racing

There are several fuses and components that affect the operation of the Fuel Injectors specifically and the fuel system as a whole.
475808

475809

475810

475811

475812
 
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