Posts
25
Joined
6/9/2019
Location
AT
Edited Date/Time
5/7/2020 5:06pm
Hello guys,
yesterday i was practicing a few laps and decided to get back to the car to get some water and rest.
I wanted to make a few final laps before going home but the bike was unable to start.
the starter is turning but there is no power to the ecu, fuel pump etc.
went back home and did some research. when i jump-wire the power relais the ecu starts up as well as the fuel pump and i can start the bike like normal. i check all the wires for rubbing/breaks and did continuity tests. As the bike is in like new shape and has never been tinkered with all the connections are ok. i checked the voltage over the coil of the power relais. The relais never gets energized it seems because there is no ground connection established. I removed the power relais and checked it seperately with a bench power supply and ohm meter, everything perfect coil reads 80ohms as it should. on other topics here i read that these people got exactly the same problem but never posted their solution:
https://www.vitalmx.com/forums/Race-Shop,42/2014-KTM-250-sxf-no-spark-n…
https://thumpertalk.com/forums/topic/1232320-2015-ktm-sx-f250-turns-ove…
It seems that the power relay gets its ground connection from the regulator when the AC phases (2 yellow wires from stator) provide voltage as soon as the rotor spins and i think here is my problem. Can it be that my regulator got fried because it was very hot outside yesterday? i made a diode check for the rectifier part which seems okay. as the regulator is very pricy i dont want to purchase it when im not 100% certain.
here is the diagram portion of the power relay (K30). The white-black wire must be grounded and leads to the regulator and also the ECU. Do you guys kno how this grounding takes place?
Best regards and many thanks in advance
yesterday i was practicing a few laps and decided to get back to the car to get some water and rest.
I wanted to make a few final laps before going home but the bike was unable to start.
the starter is turning but there is no power to the ecu, fuel pump etc.
went back home and did some research. when i jump-wire the power relais the ecu starts up as well as the fuel pump and i can start the bike like normal. i check all the wires for rubbing/breaks and did continuity tests. As the bike is in like new shape and has never been tinkered with all the connections are ok. i checked the voltage over the coil of the power relais. The relais never gets energized it seems because there is no ground connection established. I removed the power relais and checked it seperately with a bench power supply and ohm meter, everything perfect coil reads 80ohms as it should. on other topics here i read that these people got exactly the same problem but never posted their solution:
https://www.vitalmx.com/forums/Race-Shop,42/2014-KTM-250-sxf-no-spark-n…
https://thumpertalk.com/forums/topic/1232320-2015-ktm-sx-f250-turns-ove…
It seems that the power relay gets its ground connection from the regulator when the AC phases (2 yellow wires from stator) provide voltage as soon as the rotor spins and i think here is my problem. Can it be that my regulator got fried because it was very hot outside yesterday? i made a diode check for the rectifier part which seems okay. as the regulator is very pricy i dont want to purchase it when im not 100% certain.
here is the diagram portion of the power relay (K30). The white-black wire must be grounded and leads to the regulator and also the ECU. Do you guys kno how this grounding takes place?
Best regards and many thanks in advance
Battery voltage good under load?
Have you checked the starter relay?
Paw Paw
i checked the ground brown wire is coming from ktm (GND) going in to the green one on the regulator. but the green one on the reg is not connected with the chassis of reg.
when the reg is really broken i want to try a chinese replacement for 20$. In the meantime can i ride on bumping the power relay at every startup with a wire? it seems that the starting relay only has to generate a pulse and is not"on" all the time because when i dip it with a wire and remove it after the bike fired up everything idles normally.
The Shop
Paw Paw
for anyone else who has this problem i solved it now temporarely by wiring a small piece of wire in parallel to the white wire on the regulator. I just have to touch a piece of frame and start the bike afterwards. then the ECU is somehow providing ground internally for the power relay, keeping it actuated.
i found this out when i just quickly tapped the wire to ground and listenend when the relay clicked again and shut off -> many seconds after my "manual" attempt. I rode for 10hrs now with this "trick" without problems and purchased a 20usd chinese replica (which i think the original ones are cheap chinese shunt r/r too)
best regards
i think this is a good anti theft measure but it would be bad if the chinese regulator wouldnt word out of the box, now you made me curious i will plug it in one the weekend to see if pressing start button is enough to fire up
i think if the wh/bl wire would have an issue it would be most likely to touch the frame and you would hear the fuel pump turn on erratically
I had the same problem on my 14 450 sxf.
The yellow with the shrink tubing broke...
Pit Row
best regards
edit: its not even a switch, i added a wire to the harness going to the handlebar with an open end and i just touch the clamp of the clutch lever with it, the connection to the frame clamp- clamp of handlebar - trippleclamp is enough to ground the power relay, the ECU senses this somehow and holds the ground like described above
Paw Paw
Paw Paw
Ok I'm done ranting.
The issue: Cranks over but the EFI light doesn't light, the fuel pump doesn't prime and there is no spark. THESE ARE THE 3 SPECIFIC ISSUES If you just hear clicking when you press the start button this isn't your fix thread.
Three thing have to be working correctly to fix this. 1) the starter relay - event though it cranks the engine is also supplies power to other places. Make sure its good. 2) the Power Relay - Its also provides power. Make sure its good 3) The Voltage Regulator - Hard to test but they claim it can be. This is typically the problem
How to Verify - Assuming you have verified the items 1 and 2 and your battery is good. Find the white wire with black stripe on the regulator plug, back probe it with a pin or small wire so that you can ground it to the frame with alligator clip test leads. When you ground your pump should prime. When you continue to ground and press starter button your engine should start. You may need choke on. If and when it does you know your Regulator is BAD.
HINT: DO NOT BUY THE CHEAP CHINESE OR AFTERMARK REGULATOR. The KTM Regulator is special in that its able to make the white / Blk strip wire ground during the start cycle The cheap ones wont do that.
Now the bike I repaired had a bad fuel pump, or so they thought. My guess is that the pump went bad and shorted out internally and fried the regulator in the process.
Shout out to Quantum Fuel Pumps. Never have issues, much cheaper than ridiculous KTM complete pump. Works perfectly but a bit of a pain to install the fuel lines. Be prepared to throw a wrench across the garage. Change the filter too.
Any question you guys may have feel free to PM me.
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