Changing a Throttle Position Sensor

elevy

elevy

New Member
Oct 11, 2010
95
Lake Ontario
Boat Info
2007 280 Sundancer
Engines
Twin 4.3 v6s
Has anyone changed a Throttle Position Sensor? It looks pretty easy, is there a restart proceedure or anything special that I should know before doing this?:huh:

Thank You in Advance for Any Help!
 
Never done it on a boat, but on a vehicle there is a little adjustment in the sensor mounting bolts. Turning the sensor within this adjustment range will change the output voltage. The ECM needs to see a minimum voltage at closed throttle. On my 350 TBI it is 0.5 Volts. I would assume it is the same for boat ECM's as well. If the sensor is not mounted right and the voltage is too low the ECM will throw a trouble code.
 
The TPS should be a two wire device. One wire is negative or ground and the other is positive. You need to check voltage with the throttle closed between the positve wire and a good engine ground somewhere else on the motor. Sometimes you can get a connection on the back side of the wire connector, but sometimes there is not enough room for the meter lead. You can try and extend this area by putting something metal and small, like an eyeglasses screwdriver or a paper clip in the back of the connector so you can get the meter lead to connect. Just be very carefull not to let it touch the block or you could short out the sensor or even worse the ECM. If you can't get this to work, the last option is to pierce the wire with a needle or straight pin, and then read voltage from the pin to the block. Adjust the TPS until you read a little over 0.5 Volts. If you do the pin method, cover the area with electrical tape when you are done to keep the corrosion out.

Edit: Forgot to add key in "on" positon to get voltage, but engine does not have to be running.
 
Last edited:
Make sure I get this right the red lead of my meter to the positive wire of the sensor and the black lead of my meter to the engine block for ground, with key on and the pigtail connected?

Do you know if I have to clear the code from the onboard computer?
 
elevy said:
Make sure I get this right the red lead of my meter to the positive wire of the sensor and the black lead of my meter to the engine block for ground, with key on and the pigtail connected?

Do you know if I have to clear the code from the onboard computer?
Click to expand...

Yep. Make sure the block ground is good metal and not painted or anything. I don't think you HAVE to clear the code, but if there is a code set it will still be there for a reader to see. The oler ECM's you can clear by disconnecting power for several minutes and turning the key on to drain all power from the ECM. Not sure on yours.

Again, this was the proper setting for my GM truck with a 350, and I belive is also the correct setting for a 4.3L in a vehicle. I am assuming it is the same for the marine 4.3L.
 
Thank you for all the advice, I will give it a try and let you know how I make out.

Thanks Again,
Ed
 
I think you better get the voltage info from a manual to make sure. Ford has a 3 wire and off the top of my head I don't remember which colors we used. Put the smallest PIN you can find in your wife's sewing bag through the insulation and hook the meter to that. The voltage you set at idle is what I'm concerned about. Ours I'm thinking was as close to zero as possible. That's the thing though. I'm at work and I just don't remember for sure, that was 10 years ago.
I'd hate to see you set it wrong and P.O. the computer.
 
I went do last night to replace the TPS myself and after looking at it real good decided to leave it to the profesionals. Thank you to everyone for all your help and advice. This is truley a Great Site!
 
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