1989 DT115 - Throttle Valve Sensor

[Jimmy in NC]

Working on reviving an 1989 DT115 Suzuki that has been stored for 5 years. Going through the carbs it is apparent how bad the last "mechanic" was that worked on this poor girl. I have run the carbs through my ultrasonic, installed new OEM kits, and am almost ready to reinstall them. I decided I should check the 'throttle valve sensor' that sync the timing to the throttle position. According to the manual I should have 0.5V +/- 0.05V at closed throttle. I setup the test leads and Whoa! I see 12.3V. Also according to the OEM manual I should see voltage increase as throttle is applied to 2.7V or more. When I advance the throttle I see voltage drop from 12.3V to 9.0V. No worries I dig out a spare carb from the extra set that came with the vessel... same exact results.

I seriously doubt two sensors have gone bad exactly the same way; they could. I am just curious if anyone else has some input on this?

[Solarman]

The patch cable is supposed to read the voltage the ecm is sending to and from the TPS, if the test leads are not connected correctly, you could damage the ECM, or the TPS. You might be better off leaving it alone if you don't have the proper patch cable.

Good luck, post back on what you find out.

[Jimmy in NC]

I built a patch cable and checked it per the factory manual. It appears I have two bad sensors. I ordered a new sensor that should be here early next week. As soon as I get it together we will know.