2000 Suzuki DT150 Quandry.

Capt Ken

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Now it's your chance to help the mechanic. As the title says, 2000 DT150 EFI. It was given to me by a elderly customer that had sold his house and wanted it out of the yard. So working on getting it running to rehome it. Ok, the basics, spins over good, excellent compression. Fuel system was full of water, drained and cleaned. Now the oddity. If I disconnect the ignition wire or unplug the harness from the engine, the coils will fire. If I plug in the harness without unplugging ignition wire at key switch, it won't spark. Key on, the high pressure pumps powers up and pumps.
Question is, why does engergizing the ignition kill the spark unless the ECU is somehow killing it? If this was a Yamaha, it would be a cinch for me.
 

99yam40

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Not sure I can help any , but a better description of ignition wire may help others.

I take it the harness you speak of it the main harness from the controls, and where exactly are you disconnecting them?
At the motor or some where else?
 

Capt Ken

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I can either unplug the main harness at the engine and remotely spin it, it then fires. I've actually run it a second on carb cleaner. Or I can reconnect the main harness but unplug the ignition wire at the key switch and the coils will spark again. Plug the ignition wire in, no fire.
 

99yam40

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my guess is the ignition wire you speak of is the 12 volt + that runs to the ECU when Key is in the on position.
 

Capt Ken

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Correct, it powers the ECU which powers everything else like the high pressure fuel pump. Spark advance would be controlled by the ECU via the TPS, but I'm just confused why powering the CPU kills the ignition.
 

99yam40

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I am of no help on that Suzuki, I was just making sure which wires you were talking about so others knew exactly what was going on.
Seems there are not a lot of experts on Suzukis posting, so good luck

I know a guy that may have a ECU for a DT150.
If you would like, I can talk to him to see what year it is.
If my memory is correct he bought a motor to get the lower unit so he still has the power head I think
 
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lakensea

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Jan 30, 2002
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542
Check the emergency stop switch & wiring. On that model it works by grounding out the ignition through the ECM.
 

grid

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Oct 29, 2002
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Make sure your colors are properly connected. I know you said you'd removed the safety switch from the circuit, but make sure that was green removed from green, and black from black. The 12V wire should be white coming from the engine to the switch.The white wire may have a red sleeve on it. Check your voltage at the gray lead with key on. You should have 12V. If you don't have voltage, the white wire or connection--or switch-- is defective. Make sure your brown leads from the remote control are connected 1 to the switch, one to the harness. The older I get, the older the harnesses, the more I have to use a flashlight to ensure the colors are right.
 

lakensea

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Make sure your colors are properly connected. I know you said you'd removed the safety switch from the circuit, but make sure that was green removed from green, and black from black. The 12V wire should be white coming from the engine to the switch.The white wire may have a red sleeve on it. Check your voltage at the gray lead with key on. You should have 12V. If you don't have voltage, the white wire or connection--or switch-- is defective. Make sure your brown leads from the remote control are connected 1 to the switch, one to the harness. The older I get, the older the harnesses, the more I have to use a flashlight to ensure the colors are right.

Grey wire is getting power - high pressure pump would not power up without it. Brown wires are connected properly otherwise starter would not engage.

You are correct about colors as we get older, and also as the harnesses get older the colors fade - much like us.
 

grid

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I don't think the ECU is at fault. I look more toward the harness or switch. Easiest thing to do is borrow a friend's remote Suzuki switch. Barring that, I can't see anything other than ohming each wire with the switch hooked up to the harness, but not to the engine. Hook12V to the white wire at the connector plug and a ground to the black. Attach the volt/ohmmeter negative to the same negative you have going from the connector to a clean ground. Connect the POS from the volt/ohmmeter to the grey pin at the connector plug and turn the key to START. I'll bet you lose voltage. If the harness has been lying in water, I'll bet you find a cut or connection where the grey is making enough connection to give you a reading until a load is applied. The ground will do the same thing, if cut. I hope I haven't insulted anyone with this reply, as obviously you're experienced with engines. Let me know, if you win!
 
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