200 Yahama HPDI Issues - Need Help

murph21

Recruit
Joined
Apr 14, 2019
Messages
2
New here. I have a 2006 Yamaha 200 HPDI VZ200TLR. Boat sat all winter without running. Took to the water last weekend and boat surged bad at idle in neutral and in gear. If any throttle was applied the engine died immediately. Took home and drained all fuel, replaced all plugs, filters (except for mystery filters), primer bulb and line going from bulb to 10micron filter. Fired up with muffs in driveway and still surged but then went to idling at 1500 rpm in neutral but clearly running rough. Checked spark and all plugs sparking as they should in neutral and in gear. Took breather cover off and when i touched throttle linkage the sound of engine changed drastically and idled down but still more rough than usual. Don't have a harness but pinned the tps sensor and cannot get a 5v supply voltage reading from it. If you check the output side you can set to .6v and when you open the throttle the switch voltage goes down instead of up. Assuming route cause is supply voltage. Anyone have suggestions on how to trouble shoot this further?

Over the winter i installed a couple of new fish finders so i had to run cables inside the boat. Is there anything that i could have unplugged on the boat side of things that would contribute to this? I am assuming the voltage to this switch would be 100% controlled by the ecm.

Any suggestions welcome.
 

murph21

Recruit
Joined
Apr 14, 2019
Messages
2
Dug deeper today. All “pink wire” sensors are getting their 5v source power. What would cause the TPS to be the only sensor not receiving power?
Thanks
Murph21
 

rejesterd

Petty Officer 2nd Class
Joined
Sep 20, 2018
Messages
142
Yeah, I think the ECM is what controls that power supply. So if it's not correct, I would start looking at the ECM itself. Measure the peak voltage of the ECM during cranking, at 1500 rpm and 3500 rpm. The manual should give specs for that.

You can also try running the YDS tests to see if the engine is throwing any error codes.
 
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