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Discussion Starter · #1 ·
Firstly, I would like to say hello.
Unfortunately, I'm here due to the issue with my Mv.
Long story short(maybe not:)): I bought Mv f4 1000S from 2005 around 2 months ago with millage approximately 16k km. At the beginning, everything was ok. Mv started without any issues, nevertheless I did a service stuff in garage which specializes in Italian brands. After that engine worked even better, and I was extremely excited. When weather started to be better, I went for a first ride, everything was perfect until I visited a gas station. I wasn't able to start a bike after refueling. When the bike become a bit colder, it started. On the beginning, the engine works irregular, but after a minute it backs to normal. When I reached my garage, it was the same. Next day when the engine was cold it started perfectly and once again the same story. I warmed it up and when turn off I wasn't able to start. But this time, till now, I'm not able to back it to live. Starter is working and engine is trying to start(singular combustions) and nothing.

What I already did:
  • fuses check
  • new fuel pump with fuel filter replacement(I read on this forum that it was common issue)
  • new battery
What I'm planning to check (based on the service manual):
  • power relay
  • latch relay
Could you please give me some advice? Unfortunately, I know no one who have f4, to do parts switch.
Thanks in advance.
 

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Old Wing Nut
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Welcome to the family !!! Sounds like you are using a good troubleshooting process.
You might consider checking the spark plugs. The 2005 F4 uses the 1.6M ECU which has adjustable idle CO%. It is possible the bike is running too rich and you have fouled plugs.
Since it was running fine initially and then became gradually hard to start, it is likely something simple. The relays will prevent any starting at all (no single combustions as example).
 

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Discussion Starter · #4 ·
Thanks for your quick response.
Valves had been adjusted in scope of the service work, new spark plugs as well(ngk r0045q-10).
I will add sparks plugs check to my list and will let you know :)
 

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Discussion Starter · #5 ·
I had a chance to fight with MV this weekend. The first surprise was related to the rubber seal which blocked my spark plug removal tool :) I found a great thread on the forum related to this issue
I used my lathe to make my tool thinner and it this issue has been solved. Spark plugs were wet, but I could clean it by finger sweep.

In addition, a checked the intake air/temperature sensor. I found an info that if the sensor is malfunctioned, the ECU could cause spark plug flooding. And another funny story here :) In line with the manual temp should be reflected by the resistance between pins D-C (see attachment) but in my case with the sensor orientation from the manual it was between pins A-B. It is a cheap sensor, so I bought another one, and it was the same, so assume it is a bug in the manual(or maybe I read it incorrectly).

Nevertheless, with the clean spark plugs and new sensor nothing has changed :(
Do you have any other tips?
 

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That is an interesting spec for your bike. They area hotter heat range. Yes, I see the NGK R0045-J10 is one recommendation. I don't know the difference between the J and the Q designator.
I, and others, have had good luck with the NGK CR9EIX Iridium plugs.
Perhaps a plug switch is in order?

Rectangle Font Parallel Screenshot Number



Here is some more information: Spark plugs again!!!
 

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Old Wing Nut
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Those are surface gap spark plugs...pricey and not as good as the CR9EI .... And that photo shows a FOULED plug.
Get new plugs...and ditch the surface gap type. Very old technology.
 

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Discussion Starter · #10 ·
I'm suspecting that the issue is not related to spark plugs or plugs switch order based on the fact that when I took the bike from servers with this setup, the engine works perfectly.

I forgot to mention one more thing(I thought it is not important, but who knows). When the issue popped first time up, after few times of trying(in the 20 mins distance) the engine started, but 40A fuse blew up. When I replace it, the engine started perfectly. And it was the last time when engine started.

In addition, I've noticed that energy consumption is around 40 mA instead of 2÷2.5mA as manual suggesting. Now I'm planning to identify a component which over consumes power by unplugging connectors one by one.
 

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Discussion Starter · #11 ·
BTW, sparks plugs are brand new replaced during service work. I would be extremely disappointed if there is something with the sparks plugs because spent 320 euro for them :)
 

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Those plugs are for a specific application and will not work well with your situation.
You do need to find the source of electrical drain.
 

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Old Wing Nut
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Here is what surface gap plugs that were running well look like. These are the original plugs removed from my SPR 750 track bike during a major service at 6500 miles this winter.
They are the OEM plugs. They are fine, but I changed to CR9EI iridium because I have never trusted surface gap plugs (from experiences back in the 70's).
The plug you showed a photo of appears fouled to me. And yes, those plugs are way stupid expensive.

Automotive tire Camera lens Household hardware Wood Camera accessory
 

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Discussion Starter · #14 ·
Another weekend in garage brings some update. Firstly, I was able to start an engine :) Once again I cleaned spark plugs and used fully charged battery. Unfortunately, start when engine is hot is still an issue(please check the video Mv Agusta f4 hot start issue ). When the engine became cold it started perfectly.

When it comes to power drain source, I checked all plugs(I hope). Power consumption reduction I've noticed only in two cases. Power consumption backs to 2-3 mA when ECU or relay is unplugged. I'm not sure if this is the cause or maybe something behind. Nevertheless, I ordered relay( Bosch 0332019151 replacement for 800094439).

From your experience, is it possible that relay could be the cause of the issue?
 

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Part 800094439 is the Main Power Relay for the bike. If it is defective, you will have no power distribution.
Part number 800094116 is the Injection Relay and controls ignition and fuel and injectors.
 

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Discussion Starter · #16 ·
I'm proudly announcing that my issue has been solved!!!
The cause of the drain source was relay, and the spark plugs flooding was coolant temperature sensor.
There was no connection between sensor's pins (infinite resistance) what cause that ECU calculated fuel mixture constantly for a cold condition.
I ignored one symptom because I was told that it is normal, namely when temperature crosses 80C threshold, RPMs increases from 1.2k to 1,8k RPMs.
I hope this observation will help someone in the future.

Once again, thanks for your support!!! You are the best :)
 
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