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non start issue. Win a free MV Corse carbon fiber key guard

13K views 148 replies 32 participants last post by  Cybeeria 
#1 ·
If you correctly diagnose the problem, I'll send you a genuine MV Corse carbon fiber key guard for an F4.
Bike was running fine after the chip replacement. It started this morning as I was loading it onto the truck and died. Never started after that. It turns over, it won't catch.

There is spark.

There is fuel.

The ECU is fine, I tested it on another bike.

The TPS was cracked, from my leaning the bike against the door jamb, probably, but I fixed it. I even replaced it with another one and still no joy.

Ask as many questions as you like. This issue has me stumped.
 
#2 ·
Hi Carl.
First thing that comes to mind for me is to open the fuel cap and check if the immersible fuel lines are attached.
Protect your eyes if you're going to turn the ignition on with the cap open.
I hope it's something that simple.
Good luck.
 
#3 ·
No such luck. fuel lines are intact. In fact, I disconnected the fuel lines at the rail and pumped out the remaining fuel through the lines into a gas can. I thought perhaps a batch of bad fuel was causing the problem. The air box is off, and I can see fuel mist blowing into the throttle body. Spark plugs are wet also.

I'm leaning toward some sort of timing issue. The ecu is telling the bike to deliver fuel and spark, but it is not delivering the spark at the right time. That is a wild guess. I also poured a little fuel in each of the throttle bodies and tried to start it. Still nothing.

I changed the crank sensor with no positive results.

Occasionally, I will get a pop from the exhaust as if there was some combustion.

Also, it doesn't sound very MV like when cranking. It kind of booms like a Ducati.
 
#9 · (Edited)
I haven't checked the timing yet. I'm hoping it is not a valve train issue since it was running when I tried to load it and then was not.

I checked spark by removing the plugs and holding them against the frame. Each plug sparked.

But it was running before you put it in to the truck? What has changed?
My $ is on electrical - the bump as you put it on to the ramp has caused a disconnect somewhere maybe?
I presume you have done the usual preflight stuff like the sidestand switch/clutch lockout/neutral and kill switch? With all the ecu changes is it possible that one of the pins in the connectors has been pushed back?
I disconnected the side stand switch, jumpered between the two outside pins and tried to start it. No luck. I put the side stand switch back in. No luck. The only thing that changed from the time it was running until it wasn't was the side stand switch and the TPS getting cracked.

Could it be possible that the connectors on the female side leading to the wire harness are damaged? I can move each wire in the plug and its corresponding metal piece moves with it so it doesn't look like any thing on that side is broken.

I'll have a look at the connection at the ECU. I don't think that's it because as you said, it was working when I tried to load it on the truck.

I don't think it is the side stand switch or the connection there, because the engine cranks.

Hold on: If the side stand switch is disconnected, and the plug is not jumpered, the engine should not turn over, should it? Right now, it turns over whether the jumper is in the plug or not.
 
#8 ·
But it was running before you put it in to the truck? What has changed?
My $ is on electrical - the bump as you put it on to the ramp has caused a disconnect somewhere maybe?
I presume you have done the usual preflight stuff like the sidestand switch/clutch lockout/neutral and kill switch? With all the ecu changes is it possible that one of the pins in the connectors has been pushed back?
 
#15 ·
.
I might be worth taking the EPROM chip out, giving it a spray of WD40 (or something equivalent) and re-installing it.. Make sure it goes back the right way..

Sometime this works
Thanks, John. I thought of that especially since it was the chip that was giving me problems before. But I moved the complete ECU chip and all to the track bike and it started fine.
.
Dependent on the extent of the damage, it may be possible that movement between the sensor and connector have caused the connector terminals to 'splay' resulting in no or poor connection on one or more terminals, doubtful, but possible. The crimp connection between the cable and the individual terminals is normally fairly secure so also unlikely (but not impossible) that the cable has parted company from the terminal.


As long as the bike is in neutral the engine will turn over regardless of side stand position or state of the connection. However, with the side stand switch disconnected and no jumper in place you should not be seeing any spark.
Progress! or Regress! I have spark regardless of whether the jumper is in place or not.
 
#16 ·
Just double checked the wiring diagram as it's been a while since I've had to even think about an MV.

Looking at the diagram, you will get spark even with the side stand switch disconnected as the ground path it provides will be picked up by the neutral switch. So as long as the bike is in neutral it will turn over, and you'll see spark and fuel. So no further forward unfortunately.
 
#17 ·
Hate to say it, but if you have spark and gas, which you've proven, something is wrong with the timing resulting in them not being sync'd. The occasional chug/pop is probably from the build-up of gas fumes to the extent that it finally burns off when the spark hits it. Very weird to go from running to non-running like that though.
 
#18 ·
I'm thinking you may be right. It's not the latch relay. It's not the connection at the tps. The ecu is seeing a signal from all three tps wires.

I'm sure there is some electrical connection telling the injectors when to fire and how much. Perhaps something is wrong there and I'm getting way too much fuel or not enough.
 
#22 ·
I'm thinking you may be right. It's not the latch relay. It's not the connection at the tps. The ecu is seeing a signal from all three tps wires.

I'm sure there is some electrical connection telling the injectors when to fire and how much. Perhaps something is wrong there and I'm getting way too much fuel or not enough.
Have you had a look at the crank timing sensor Carl, mine did the same thing after a re-build. Somehow it had come loose and the bike turned over but just popped every now and then.

I know it is a bit weird but check the battery voltage. I have found mine to be very sensitive to voltage. It can have enough juice to crank but then not start.
One other thing is the tip over sensor requires the ignition to be cycled fully off in order to reset.
The bike does not turn over at all with the tilt over sensor activated, and you are right, turning the bike off and then back on resets it.
 
#19 ·
I know it is a bit weird but check the battery voltage. I have found mine to be very sensitive to voltage. It can have enough juice to crank but then not start.
One other thing is the tip over sensor requires the ignition to be cycled fully off in order to reset.
 
#25 ·
12.3 volts on either side of the fuses. I've been alternating between two batteries. Is that too low? I haven't taken a reading at the battery posts.

Will it fire up if you hold the throttle wide open? My bike did this to me twice last week, from cold it wouldn't fire up unless it was wide open, as if it was flooded. But then it's been fine since....
No. Not at all. I tried that. A little flame from cylinder #2 once in a while, but not even a stumble.
 
#21 ·
I'm still going back to what has changed...Don't you have to do a TPS reset if you change it? Have you tried subbing another TPS on the chance that the new one is dodgy?
Are you actually getting spark on every plug?
Are you able to address the ecu for a fault code?
 
#24 · (Edited)
I only have two TPS units. The one that broke and the one on the bike now. Both "work" in so far as when connected to an ohm meter the voltage changes when you turn the back of it. (simulate the butteryflys opening and closing.) Yes, getting spark at every plug. I don't have any equipment that would allow me to read a fault code. Where would I buy a code reader or diagnostic tool for the bike?

Have you had a look at the crank timing sensor Carl, mine did the same thing after a re-build. Somehow it had come loose and the bike turned over but just popped every now and then.


The bike does not turn over at all with the tilt over sensor activated, and you are right, turning the bike off and then back on resets it.
I changed the crank timing sensor with no positive result. The bike is an '04.

putting back other chip? rarely the breakdown too.
check camshaft timing wheel bolts?
Camshaft timing wheel bolts? I'm not sure what you mean. I haven't opened the stator cover to see if anything is going on in there.
 
#28 ·
You have a picture of that Dons? There is nothing above #4. The only wires coming out of the cylinder head or cylinder is the temp sensor.

Other #4 Carl, I'll just check if the 750 is in the same spot as the 1000 - R/h side. Give me a sec.
 
#30 ·
Bugger again

Okay you don't have the cam sensor on the 750 Carl, I am just going throught the drawings now. Keep in the back of your mind always that it ids likely something to do with what oyu have done so far, that's the norm. But, and there is always a but.
Take the F4 cover off and have a look at the timing wheel and sensor (Phonic wheel ? ).
 
#32 ·
Carl....do a compression and leak down test. Low compression with a low leak down would indicate cam timing is off. High compression can also indicate cam timing is off. Low compression and high leak down would indicate mechanical damage...listen for the air from the leak down tester to determine if valve sealing or piston sealing is cause (out the breather or oil fill is piston/rings).

My bet is the timing chain has jumped.
 
#33 ·
Ouch Ed

Carl....do a compression and leak down test. Low compression with a low leak down would indicate cam timing is off. High compression can also indicate cam timing is off. Low compression and high leak down would indicate mechanical damage...listen for the air from the leak down tester to determine if valve sealing or piston sealing is cause (out the breather or oil fill is piston/rings).

My bet is the timing chain has jumped.
I hope not, but possible, how do the 750's go with bending valve's when this happens?

Measure the crank position sensor with a Ohm meter, I think 680 - 700Ohm the book says, and a gap of .6-.7mm on the timing wheel.
 
#37 · (Edited)
That's a low voltage reading Carl.. My project bike battery was charged in December and hasn't been charged since and the voltage is 12.5 Volts at the poles.

I would just fully charge the battery if nothing else to eliminate it from enquiries. I imagine you are anyway : )

My guess is your bike will fire right up once the battery is up to between 12.7 and 13.5 Volts ( nominally as I haven't got the text book here ).

joe
 
#38 ·
Battery charging has begun. I'm charging 3 of them. In the mean time, the compression numbers don't look good. They range from 70psi to 145psi. That may be because the battery was weak and I'm not spinning the engine fast enough.

Are cylinder pressures on the 750 supposed to be in the range of 100 to 200 psi. (7.7 to 14 bar.)
 
#41 ·
It has to be more simple that a timing chain. Bike running. Bike Bumped. Bike not running.

Cindy's Brutale would not start, but it would turn over, with a weak battery. Eject Koyo, enter Yuasa, bike starts.

I am with Joe. Low starting volts = low starting amps = no go.

Charge up a battery, make sure grounds and ther connections are clean and tight. Hook up a starter/charger and let 'er rip.

FWIW, if the battery is damaged such that it has become a load, the bike won't start even with a good charger/starter hooked up...the ECU will see an over voltage condition and shut 'er down.

I saw that on the Brutale before I ponied up for the Yuasa.

K.I.S.S. and check on the last thing done...i.e. bump.
 
#42 ·
Battery measures 13.4 with a charger on it, 12.9 with the charger off.

Removed valve cover and phonic wheel cover. phonic wheel timing mark and #1tdc are perfect. Cam timing lines look perfect. Valve clearances both intake and exhaust are within spec.

Too complicated things are checking out fine. Therefore, I must be doing something stupid.
 
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