I am going crazy trying to figure out what is ailing this quad....start it up cold and it starts normal runs fine, you can get on it, run it hard, run it easy and no problem, the problem seems to happen when it gets warm, (5 mins or so) seems to happen when u give it full throttle then let off, is when the problem starts, and then its a consistent misfire as if its every other revolution of the motor it misses... when it hits this point, it won't idle, and starts really hard..

Ive checked timing, and valve clearances, they seem good

FI light is operable but does not light

fuel pump is less then 6 months old

new battery

I can tell you that the tps sensor line when put into dealer mode is not in the center and i can't seem to get it to even move let alone get it in the center, even if moving it extreme one way or the other... any ideas? thanks in advance

 

Have you cleaned out the filter in the injector? This is the most common problem with the big Suzuki injection systems, I assume the tank filter is OK as you get a new one with the pump. I have had similar problems with a faulty coolant temp sensor, (it was the wires to it) but this did fault code, it is just possible the sensor is giving the wrong info to the ECU causing it to alter the mixture.

Getting the tps line in the centre can be difficult, does the line jump when you rev the bike up?

 

I have not cleaned the filter out in the injector... i wasn't really aware there was one there, i was tinkering around last night and started it cold, let it idle for a good 20 mins, moved the tps from one extreme to the other and it seemed to change the idle of the bike. at one point i did get the line to move and then it seemed to not move anymore i can't tell u when the seize of movement happened.


After idling for 20+ (fan kicked on and off) i revved it up a little first couple revs it was normal and then its like you flip a switch and it starts missing and will do so until it goes back to a cold cycle... I have a video of it on my phone but am unsure how to go about getting it on here. also as a side note i checked voltage at the battery when it was running and missing, and had 13.5 volts so i think that is all in check

 

Also if this helps.. once it goes into (missing mode) if you spray starting fluid in the intake it doesn't equalize out, if it was a fuel issue wouldn't you think it would?

 

Does it have a port to pull codes from? Sounds like a bad sensor...

 

Starting fluid won't smooth out an EFI system, the sensors get conflicting information and upset the fueling. Clean that filter out. Poke down the injector inlet very carefully with a tiny screwdriver, then blow out with compressed air, you can see if the filter screen inside is clean after doing this. You will never get the TPS right with a blocked filter, they don't seem to sit "on the middle line" too well anyway.

Just a thought, could be an ignition problem, faulty plug or coil.

 

I havent gotten a chance to check filter in the injector, but will hopefully in the next couple days... is the filter physically removable from the injector or is compressed air the only way to clean it?

As for the port on to pull codes from it has a port that you can put the display into "dealer" mode but i have no codes, come up... I dunno if the actual device that is made to plug into so called port provides more info then what i can pull from putting it in to dealer mode or not...

As for faulty ignition, the plug becomes very carboned up from missing, i have a regular spark plug cleaner and it doesn't help, plug looks to be in nice shape and the tip isn't burnt or anything... faulty coil? i dunno how to go about checking that other then i can tell u when it goes into its fit, the spark still looks strong and shocks ya good as i slipped the one time while checking for that! lol

 

For a couple of dollars, fit a new plug. The system fault codes if the coil doesn't spark for a few revs, but if the coil was intermittently sparking it may not get to the "no spark" threshold. I suspect that if the system doesn't fault code, it won't signal a fault to the computerised checking system either.

The filter doesn't come out of the injector,

 

Update: Ive tried a different (used) plug, no difference, put a fuel pressure gauge on the fuel system and have about 40psi when running...

Noticed the other night while messing with it that the header pipe gets hot enough to glow slightly when its idling after startup, and when its not missing if revved up the glowing gets worse and it becomes cherry red-this tells me that i have a lean issue.... i didn't proceed any further when i saw this i returned it to idle and shut it down... however i have a carboned looking plug when its removed so that tells me a rich problem, so my question is could it be lean when not missing and rich after it goes into its fit?

another side note, last night i started it up to observe some more of it, and it did something it hasn't done this whole time, after idling for about 5 minutes it just shut off, and threw a code for the tps... now is that a sign or is it because I've had the tps in every position possible and have that messed up? is there a way to check the tps with a multimeter somehow?

 

"Clean that filter out."