Fz6 no enciende caliente

[LeviV]

In full 2024 month 10 I have the same problem .. Fz6-s s1 2008 with oxygen sensor lambda probe
1. If someone solved the problem, please give us the information.
2. I will tell you what I have done to the motorcycle to date.
Fault: when it is very hot it does not turn on. When it turns on it is after 5 minutes, 10 minutes, sometimes it turns on when the fan is on, other times I open the switch the rpm needle goes up when it goes down halfway I give star it turns on and other times it does not work conclusion the PROBLEM is not punctual because it works or does not work with different temperature parameters.
What has been diagnosed or changed:
-ECU changed for ECU Fz6 s2 American version without immobilizer
-New original Yuasa YTX14BS battery with higher amperage
-New original BS brand yt12-b4 battery
-Throttle body harness
-IAT sensor
-MAP sensor
-Semi-new fuel pump, new battery
-Engine vacuum synchronization
-Coin calibration, valve settlement, mechanical chain tensioner, new original chain guides, new original chain
-Branch and ground repair
-Semi-new injectors
-Alternator recently wound
-Semi-new original regulator
-CKP was also replaced
-New original clean K&N filter
-New NGK iridium spark plugs
-Semi-new ignition coils
I don't know if I'm missing another detail that I've already done. With the knowledge I have as a specialized electronic, electrical and mechanical technician that I am, I know that it is a fuel problem when it is hot it does not send the correct amount of gasoline to start the engine.
History when the problem improved 1 year ago when I started restoring
- I managed to temporarily solve it by feeding the injectors with a power cable directly from the battery and with a car fuel pressure regulator that maintained the 40 psi fuel pressure, but then I put everything back in and it failed again
And right now the bike is in that situation and more than one in my country has that problem.
WHO HAS DEFINITIVELY SOLVED THIS PROBLEM?

 

[lrojasma]

In full 2024 month 10 I have the same problem .. Fz6-s s1 2008 with oxygen sensor lambda probe
1. If someone solved the problem, please give us the information.
2. I will tell you what I have done to the motorcycle to date.
Fault: when it is very hot it does not turn on. When it turns on it is after 5 minutes, 10 minutes, sometimes it turns on when the fan is on, other times I open the switch the rpm needle goes up when it goes down halfway I give star it turns on and other times it does not work conclusion the PROBLEM is not punctual because it works or does not work with different temperature parameters.
What has been diagnosed or changed:
-ECU changed for ECU Fz6 s2 American version without immobilizer
-New original Yuasa YTX14BS battery with higher amperage
-New original BS brand yt12-b4 battery
-Throttle body harness
-IAT sensor
-MAP sensor
-Semi-new fuel pump, new battery
-Engine vacuum synchronization
-Coin calibration, valve settlement, mechanical chain tensioner, new original chain guides, new original chain
-Branch and ground repair
-Semi-new injectors
-Alternator recently wound
-Semi-new original regulator
-CKP was also replaced
-New original clean K&N filter
-New NGK iridium spark plugs
-Semi-new ignition coils
I don't know if I'm missing another detail that I've already done. With the knowledge I have as a specialized electronic, electrical and mechanical technician that I am, I know that it is a fuel problem when it is hot it does not send the correct amount of gasoline to start the engine.
History when the problem improved 1 year ago when I started restoring
- I managed to temporarily solve it by feeding the injectors with a power cable directly from the battery and with a car fuel pressure regulator that maintained the 40 psi fuel pressure, but then I put everything back in and it failed again
And right now the bike is in that situation and more than one in my country has that problem.
WHO HAS DEFINITIVELY SOLVED THIS PROBLEM?

Even so multiple people has the same symptom, doesn't mean is the same problem.

One thing that you must understand on these bike is that, they are very simple (Fortunately), so not many things to fail.

One engine doesn't turn on by these 4 reasons.

1 Fuel
2 Ignition
3 Timing
4 Compression

Fuel: The injectors must atomize gasoline in a exact point at a constant pressure, so the fuel pump must be capable of deliver such pressure at any given time, the fuel pump assembly has a pressure regulator for this to be possible, the fuel pump motor will deliver always constant pressure, mostly higher than the engine requirements, the fuel regulator is the one that regulates that, returning fuel to the tank when that pressure is higher than the regulator spec, remember this is a common rail system, so if you want to diagnose this part correctly you need to test pump pressure but using a series system, not just testing the fuel pump, testing it while on connected on the rail, the way the service manual specify.

If the regulator is worn out, is possible that, at some times it opens and the fuel pressure declines

On the fuel department other cause could be the injectors itself and the one controlling them, the ECU, the ECU send open signals to the injectors in a timing controlled by a static table embedded on the ECU that works based on the multiple sensors that the bike has, so if any of those sensors fail, the ecu fail, the cabling, etc, the bike will just not turn on.

If the failure is only in hot and this is the cause, it could be the injectors coils are failing when hot or the ECU solder points inside it, are failing (All Yamaha's are known to have this issue from time to time), so when hot, the solder joints fails and when cold, it start again.

You can rule out the inyectors by using the diagnostic mode, they are 4 tests 2 tests for the injectors and 2 tests for the coils, both on pairs, but another way is to take out the airbox and you can using your eyes, see the injectors delivering fuel, it's fast but it's visible with the naked eye.

One way to test this is, when it doesn't turn on, take out the ECU screws and hit the ecu while trying to start the bike, if those hits makes the bike start, now you now you have a cold solder join problem on the ECU, and it doesn't matter if you already change it, the new one could have this problem too, is very common, mostly on S1 models, but S2 too.

On the fuel department too, we have the pick up coil, that coil tells the ECU the position of the crank, if the position is off, the fuel delivery will be off too, but that is easily tested with a tester, and you will notice that the measurement will change from cold to hot, but as long it's withing spec, everything is ok.

Ignition: The ECU send signals to the coils in pairs, and it detects them too, so you can check with the diagnostic mode as mentioned before, these tests will send individual signals by pairs of coils, you can even take out the coil stick from the engine and see the spark, the test send 5 signal by pair.

Timing: If the timing is off, obviously, everything will be fucked up hahaha, so, nothing else to say here.

Compresión: This one is very misunderstood, because people tends to think that compression is always the same, and the compression will vary with temperature, and this is important, because another VERY COMMON ( SUPER COMMON ) problem with any bike is that, trying to get a quier engine, the valve adjustment is abused and sometimes wrong performed.

The problem with quieter engines is that, you are FOR SURE not sealing entirely the cylinder chamber when hot.

Let me explain:

Let's say, you adjust the valves in cold withing spec, BUT you made a mistake a maybe some valve was over adjusted, just by a little. Yes the engine cold will turn on, the valves are sealed anyway, and the engine will be quiet, purr like a kitten. But... when the engine gets hot and the metals expand, that little room that you left on the valve will be quickly filled, making the camshaft contact the valve constantly, so leaving the valve open, so the compression will be lost.

When the engine is already running this will be no problem because everything is so fast that the engine doesn't have time to use the entire compression cycle so it works, not a 100% even if you dont notice it, but it will work. But... when you turn off the bike, that compression missing will be need it, and the engine WILL NOT TURN ON! until it get a little cold, just with 5 minutes is enough, or you can even start the bike using push start.

As you can see, there is A LOT of reasons that can cause the same behavior, so even if you fix your issue somehow, it doesn't warranty that the same solution will apply to another person, this in regard that you said that in your country a lo of people has this issue.

My advise is...

Try to determine which of the big 4 that i mention, is the one causing the bike not to start. Is coil ignition? is fuel? or is compression at hot being low? and you could try hitting the ECU when the bike doesn't start, that at least will give you some idea if the bike starts, but the main advise is. Dont do what you already did, start changing things just because, without any proper diagnosing, you will easily end up changing half bike and even not finding the issue hahahaha

 

[TownsendsFJR1300]

When it's not starting/acting up, have a spare, known, good spark plug handy.
Pull the #4 plug wire & plug in your spare spark plug into that wire, ground and check for spark.

If you have spark, have the tank loose, (or let the bike get hot sitting/running).
Have the air filter removed. When it acts up, spray starting fluid/carb cleaner
down the TB's and see if it licks off.

We need to start ruling things in or OUT methodically...

.