89 Suzuki DT85 Throttle Valve Sensor

[nbaker]

I have a power problem with my 85 hp Suzuki. At first it would not get put on plane. I have rebuilt carbs, fuel pump and new bulb and connector. The boat will get on plane after awhile and seems to run fine once there. But he has no power getting out of the hole or trying to put it back on the trailer. I was testing the throttle valve sensor (IC system) today. The sensor burned up with only about 9.5 volts applied to it. Connections were correct, black/red lead to the power source(variable power supply), black lead to ground and green/red to the volt meter. Don't want to burn up the new sensor when it comes in. Any ideas why it burned uo?

 

[reeldutch]

Re: 89 Suzuki DT85 Throttle Valve Sensor

The TPS on those models as well as the 90hp v4 are very finnicky.

basickly what they messure is resistance.
the ignition module aply's some voltage to it. and mesures the return. the difference is where the module thinks the trohtle valve is.
i believe the reference voltage is 6 volts coming from the module..

the way to test the TPS is a resistanse test.

mesure the closed position and the open position.
they should be in spec.

if thats ok you wil have to be very presize and instal the tps in the right position..
thas where the problem usualy is.

get a manual all the specs are in there.
i believe its .6 ohms and .275ohms
somewhere in that range.
but get the specs.

 

[nbaker]

Re: 89 Suzuki DT85 Throttle Valve Sensor

Thanks for your reply. I do have the manual and was following the instructions completely. The voltage at idle is .45 - .55 volts and 2.7 volts at full throttle. What I am wondering is why would this sensor just burn up doing the test in accordance with the manual. I have the Clymer Suzuki manual and have seen other threads that say the Clymer books are not that good. I just want to make sure this manual is giving me the correct procedure before the new sensor comes in. I have to follow this procedure to setup the new sensor and at $130.00 I don't want to burn up another sensor.

 

[gsyfishy]

Re: 89 Suzuki DT85 Throttle Valve Sensor

You're correct on the voltage readings, i believe it says to hook up a 9volt battery in the circuit for the test, The V4-V6 of that year the test is conducted using resistance.

 

[nbaker]

Re: 89 Suzuki DT85 Throttle Valve Sensor

The Clymer book says 9 volt minimum. I have the new parts coming tomorrow with a factory manual. I will post what the factory manual has to say about this procedure.

 

[nbaker]

Re: 89 Suzuki DT85 Throttle Valve Sensor

Installed the new sensor this past weekend. The factory manual's test/set up procedure is just like the Cylmer manual except the minimum voltage is 6 volts and not 9. Applied 12 volts and adjusted to specs. Took the boat to the lake and checked for full power. At first it was still only making 3000 to 3500. Intermittently it will now go to 4800 to 5000. I am not getting any lights but something must be causing it to go into rev limits! Will check oil, water and rev sensors. Has anyone seen this before with not getting any lights or warnings sounding? Waffles just checked my title and mine is also an 88. Sounds like we are having the similar problems.

 

[waffles1]

Re: 89 Suzuki DT85 Throttle Valve Sensor

We are close with the same symptons only mine never gets higher then 3500-3800 rpms and has a slight miss at idle and runs a little rough. Mine doesn't sound bad at wot, it just doesn't seem to run as good as it did before the throttle linkage was adjusted. Tha's when I started to notice my problems. I'm just not sure how much it was moved. My buddy thought he could get a few more rpms by adjusting the throttle more. bad idea. Thanks

 

[nbaker]

Re: 89 Suzuki DT85 Throttle Valve Sensor

Just wanted to post the throttle position sensor cured my problem. Took it to the lake today and it jumped up on plane and reached 5500 rpm. Before I went on vacation I took the boat to a local river access. I did not take it off the trailer and I found out that the engine won't make full power while on the trailer. So I thought the problem was still there. I was told to take it to the lake and all is well.