1996 mercruser 7.4 mpi…

F

Fuelish money

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1996 mercruser 7.4 mpi LX.. I replaced throttle position sensor and I still get a code. Once I replaced it I cleared the code. I put the boat in the water fired it up and let it run a little while. I repeated the process several times but when I go to check for codes I get the code for throttle position sensor. Will this go away after I drive it a few times on the lake? I also notice a higher than normal idle too.. the sensor has two screw holes so I don’t thing this can be adjusted.. any advice? Thanks.
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Fun Times

Fun Times

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How are you checkong for codes? do you have a scan tool of some sorts? Code number is?

If you have scan tool, you'll need to see what all the throttle percentage values are to see if they are in range....While it's very minimal, you can sometimes get a small adjustment while watching the TP voltage of the scan tool while tightening the screws slowly while trying to turn it.

Check the idle speed with the throttle cable disconnected…. What RPM are you seeing when fully warm at minimum 154 degrees up to 163ish degrees?

Clean both sides of the throttle body plate all around it too if you haven’t.
 
F

Fuelish money

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Fun Times said:
How are you checkong for codes? do you have a scan tool of some sorts? Code number is?

If you have scan tool, you'll need to see what all the throttle percentage values are to see if they are in range....While it's very minimal, you can sometimes get a small adjustment while watching the TP voltage of the scan tool while tightening the screws slowly while trying to turn it.

Check the idle speed with the throttle cable disconnected…. What RPM are you seeing when fully warm at minimum 154 degrees up to 163ish degrees?

Clean both sides of the throttle body plate all around it too if you haven’t.
Click to expand...
I found a trick online to read the codes with a 12v light and a paper clip to jumper the dlc. When I replaced the sensor I put my volt meter ground to the ground terminal on the battery and the red lead to the blue wire on the tps harness. I adjusted the sensor while watching the volt meter to ensure I set idle at 0.7 and wot at 4.5 per my manual. I then put everything back together fired it up and the idle sounded great (700-750 rpm) throttle response was great no hesitation like before. So I let the boat run on the muffs for a little while cycled the key on and off a few times. Revd the boat up a few times all sounded great. Turn the boat off check the codes and the code 21 popped up again which indicates throttle position sensor. I cleared the code fired it up and repeated the process and when I turned it off the second time I checked the codes and seen I still had code 21 reappear.
 
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CayugaCobalt

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Fuelish money said:
I found a trick online to read the codes with a 12v light and a paper clip to jumper the dlc. When I replaced the sensor I put my volt meter ground to the ground terminal on the battery and the red lead to the blue wire on the tps harness. I adjusted the sensor while watching the volt meter to ensure I set idle at 0.7 and wot at 4.5 per my manual. I then put everything back together fired it up and the idle sounded great (700-750 rpm) throttle response was great no hesitation like before. So I let the boat run on the muffs for a little while cycled the key on and off a few times. Revd the boat up a few times all sounded great. Turn the boat off check the codes and the code 21 popped up again which indicates throttle position sensor. I cleared the code fired it up and repeated the process and when I turned it off the second time I checked the codes and seen I still had code 21 reappear.
Click to expand...
This is very interesting. Could you post the online link where you found this technique and a photo of your light/ jumper clip set up?

Your engine bay looks immaculate. Good job Cpt.
 
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