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Discussion Starter #1
Hi folks hoping you can give me some advice on my problem. I’m going to try and give you as much info as possible so sorry this is a bit long!

Bike is a 2006 F4 1000S. I’ve owned it since 2011 and it isn’t ridden much 5.8k miles total. It has a Power Commander III (not sure if relevant). It’s always serviced by an MV Dealer and I always use Super Unleaded.
I took it out and did 80 miles with no problems a few weeks ago. Went for a ride last week and although I probably had half a tank, decided to fill up after about 20 miles. Got back on the road and about a mile later the engine just died, no spluttering or warning whatsoever. The instrument lights came on. I parked up and waited a few minutes, switched on and it started albeit having to give it loads of throttle. Got half mile then the same thing happened. Repeat twice more. Got recovered home.

With the bike home and cold it started but again with loads of throttle needed. It run on idle for about two minutes then cut – no spluttering it just cut. I then noticed that in this state if I pressed and released the kill switch the fuel pump did not prime. If I switched off the ignition and straight back on the Pump primed but only for about 1 second. Um……

I looked at some old posts and they gave me lots of areas so check and the Service Manual to read and so this is what I’ve done:
  • Checked breather hoses and fuel cap for any vacuum- all ok
  • Checked fuse #6 - ok
  • Tank off and fuel pump out – Actually very clean in there
  • Replaced Fuel pump filter, cleaned filter at bottom of the pump, checked all hoses - all ok
  • Hooked up pump to test while out of the tank – Same symptoms
  • Tested pump with a 12v supply – spins up every time no problem
  • Checked continuity of the Kill Switch, Side Stand Switch – All ok
  • Swapped over the relays either side of the ECU – Same symptoms
  • Now I am stuck. I have limited knowledge but what I’ve gleaned is that the ECU sends a 3 second timed power signal via the relay to the fuel pump which then goes continuous once the kike is running.
Interestingly if the bike sits for 15 mins or so when I switch on, the fuel pump primes for about the 3 seconds it should. But if I switch of and on it primes for what seems a random duration 1-2 seconds, sometimes no at all. The kill switch never seems to trigger priming. I’ve got an awful feeling it's the ECU but hey I'm a complete novice so hoping you can help..

Normally I would get it to my dealer but he is corona-closed. If anyone can assess these symptoms and what I’ve done so far and make any other suggestions I would be immensely grateful

Cheers
Dave
 

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Well, the place that I would check first is the Start Solenoid connections on the left side of the bike. They live behind the mid fairing panel and tend to fail in time. Look for signs of overheating and cracking.
What is your battery condition?
 

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Would follow Chuck's suggestion first...easy check.

Kill switch only does not trigger pump prime as the ECU power was not interrupted.
Not sure, why the random prime times when key on soon after key off.... Maybe a fuel pressure test is in order. Unfortunately, that will require something to measure it with that you probably don't have and will be interesting to make.

So...
  • Fresh good fuel (not what you filled up with when all this started).
  • New fuel filter and clean strainer.....how were your hoses?
  • Engine will start, just not without a lot of air and advanced TPS reading to the ECU, and makes no ugly mechanical sounds.
  • Fuel pump runs... (Does it stop running while the crank is still turning??)
Disregarding the pump prime tie question.....how about the spark plugs??? You know, fouled plugs can cause similar symptoms (hard start, stall, won't run).
 

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Discussion Starter #4
Thanks both. Checked solenoid and there is no signs of heat or other damage. Battery is about a year old, sealed type. I get 13.23v at the battery and at the solenoid.

As mentioned in my post I changed the fuel filter and cleaned the strainer (at the bottom of the pump?) it was pretty clean anyway. I checked fuel hoses around the pump and to the Injector rail and the breather hoses - all ok.

Thanks for the info about the kill switch, that is also useful to know!

When it's running it is sweet but then it just drops dead - LOL

I haven't started it since doing all the stuff I checked. I'll get some fresh fuel, check the plugs and check if the fuel pump runs while the crank is turning, and report back.

Cheers guys
Dave
 

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I had very similar symptoms.
Mine was a battery ground connection which had vibrated loose.
An easy check to do.

Often we search for complex solutions to the simplest problems.

So, a battery drop test ...
A check of alternator output...

My few cents is on a battery or battery connection issue.
 

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Ah yes... Power Commander..... First step when dealing with any running problem on a bike so equipped...disconnect the Power Commander.!!!
 
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My fuel pump primes every time I turn the kill switch off and on. When you ran your fuel pump test, did you see how much volume of fuel it was able to pump? Did you block the flow with your finger to see if it's making decent pressure? What I've done in the past to rule out electrical problems in the SPU related to fuel pump and injectors is give +12V from the battery directly to the fuel pump / injector. If you want to be safe, remove the fuse. Use a volt meter to find out which spade for the fuse is getting +12V when the pump primes. That's the spade that goes to the power relay. The other spade goes directly to the pump and injectors. You'll want to give this spade +12V from the battery. It goes straight to the pump and injectors. If you start the bike and it runs well like this, your problem is upstream from there (Power Relay, SPU, sensor(s), CPU, wiring for those things...

I don't know about your F4, but my 910R's power relay is in the SPU. I had to replace my SPU a year ago for fuel pump / injector problems and just yesterday had to repair the new SPU for the same problem. Although, my problem was intermittent sudden death that got progressively worse. Yours runs when you give it gas. Mine would just straight die.
 

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Interestingly if the bike sits for 15 mins or so when I switch on, the fuel pump primes for about the 3 seconds it should. But if I switch of and on it primes for what seems a random duration 1-2 seconds, sometimes no at all. The kill switch never seems to trigger priming. I’ve got an awful feeling it's the ECU

Cheers
Dave
The random priming sounds familiar. When my first SPU died, it was doing the same thing. Sometimes it would prime 3 sec, sometimes less, sometimes not at all. SPU is much more likely to be faulty than the CPU (ECU).
 

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The F4 does not have an SPU. It has separate relays for those functions.
 

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Discussion Starter #13
Hi all - It's been a long journey but my F4 is fixed!


Thank you all once again for your input and advice. Boy have I learned a lot.

So the story…As you'll recall the bike died straight after i re-fuelled with Super as I always do and it would often start then die after a minute or so then random fuel pump prime times.

Various replies suggested checking Power Commander Injector connections, Start Solenoid, Battery Ground and Drop Test, Alternator test etc in addition to the battery of tests I'd already done. So, I went through these and could find absolutely nothing. I was working my way inexorably back to the ECU with some fear and trepidation. I recorded a load of videos as a I went planning to put them up here.

Then, having got nowhere I decided to re-fit the fuel pump in the tank and connected it up to the bike and try it again. In the following video you can the ignition switch being turned on and the pump priming normally. Then at 3 seconds there is the sound of what I can only describe as an electrical short circuit. I turned my phone to where the sound was coming from and some more re-cycles and you can hear on the video the pump either doesn’t prime at all or only primes for a brief moment..

Fuel Pump Prime Test.mp4

Did a few more tests listening carefully to where the cracking sound was coming from and then I found it….

20200615_184049.jpg

Yep the alarm. I remembered that it was replaced in 2015 by a mobile alarm guy. So I called him up, explained the symptoms and he said he was pretty sure it was the alarm and the model he fitted was actually the subject of a recall and he would send me a new one FOC! As this alarm is wired deep into the loom it is not possible to bypass it so I duly waited. Yes when the new alarm arrived I fitted it and she fired up first time.

Note that the Kill Switch does prime the pump every time it’s pressed as I thought it did originally.

For those of you in the UK the Alarm guy I used is called Pete Mouncer. He’s a top guy would thoroughly recommend. Bike Alarm Man. UK Motorbike Alarm Fitters and fitting service. Motor cycle security systems, accessories and spares. Free UK Shipping! "The Motorcycle Security Experts"

Cheers all and thanks again. Time to get out there!

IMG_0348.JPG

Dave
 

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Fucking alarm systems cause more grief than they are worth.
 

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That must be like the alarm that was fitted on a bike I got a wiring loom from (purchased for connectors).
It had alarm wiring that was spliced in deep within the harness.
Happy you tracked it down.
 
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