GL1200 LTD Throttle Position Sensor Help Needed


Information and questions on GL1200 Goldwings (1984-1987)
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RockinRon
Posts: 2
Joined: Mon Feb 18, 2019 7:05 pm
Location: maricopa, az
Motorcycle: 1985 GL1200A Aspencade

GL1200 LTD Throttle Position Sensor Help Needed

Post by RockinRon » Wed Mar 13, 2019 5:03 pm



I have looked around and found several posts regarding this topic but I am still a little confused about how to set the TPS. The Honda manual describes taking voltage measurements (input and output) from the leads to the TPS, red and green for the input voltage, and white and green for the output voltage. The wiring diagram and what I am seeing on the bike are Red/White, Light Green, and Green/Blue wires.

I have removed the bolts holding the TPS so I can adjust it, but don't understand which wires I should be checking to adjust the output voltage to the desired and recommended voltage (0.475 to 0.495 volts).

Thanks.



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Rednaxs60
Posts: 2005
Joined: Wed Nov 18, 2015 12:44 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1985 GL1200 LTD
1995 GL1500 SE CDN Edition
2008 GL1800 (sold)
Ontario 1985 GL1200 LTD (sold)

Re: GL1200 LTD Throttle Position Sensor Help Needed

Post by Rednaxs60 » Wed Mar 13, 2019 9:14 pm

To set the TPS you need to use the light green (signal) and green (ground). You should also do a cylinder bank balance and set the idle first. The cylinder balance screw is under the CFI cover on the right and balances the cylinders by adjusting the left throttle linkage.

You need to use the TPS calibration screw on the left throttle linkage. This screw comes up tight on the throttle linkage then you insert a 2.9 mm feeler gauge for the correct throttle opening. This process is detailed on page 10-25 of the supplement.

Another issue you may want to confirm is that the cruise control cancellation using the throttle works. This is where you cancel cruise by twisting the throttle closed. This linkage is in the middle of the air chamber close to where the left/right throttle linkages join. If this is "frozen" and you free it up you will have to go through the process of calibrating the TPS, setting the idle and doing a cylinder balance. Working on this now because I did the heads, cleaned the air chamber, installed new vacuum hoses.

Do you have the manuals for the bike? PM sent.

Cheers
"When you write the story of your life, don't let anyone else hold the pen"

Ernest

RockinRon
Posts: 2
Joined: Mon Feb 18, 2019 7:05 pm
Location: maricopa, az
Motorcycle: 1985 GL1200A Aspencade

Re: GL1200 LTD Throttle Position Sensor Help Needed

Post by RockinRon » Thu Mar 14, 2019 10:58 am

Thanks.
I synchronized the banks and set the idle screw when I first bought the bike a month ago but afterwards it was running very rich on all cylinders. That's the problem I am currently trying to solve. I will try your suggestions.

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Rednaxs60
Posts: 2005
Joined: Wed Nov 18, 2015 12:44 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1985 GL1200 LTD
1995 GL1500 SE CDN Edition
2008 GL1800 (sold)
Ontario 1985 GL1200 LTD (sold)

Re: GL1200 LTD Throttle Position Sensor Help Needed

Post by Rednaxs60 » Thu Mar 14, 2019 8:15 pm

Had the same issue as you mention, fuel smell on start and running slightly rich. Since I freed up the cruise throttle cancellation plate, I've had to reset the TPS twice. Think that this contributes to the running rich and a fuel smell when starting and during operation. Even though you can have the TPS set, cylinder banks balanced, and the idle where it should be, I would submit that the engine is operating in the rich zone. Hoping this is a correct theory, will find out tomorrow when I finish installing the air chamber, had it out to investigate an air leak and the only way to do that is to remove the air chamber.

You can check to see if the throttle cruise cancellation unit is working. If it is not frozen, you can see the plate move. This plate is behind the throttle linkage in the centre of the air chamber.

Cheers


"When you write the story of your life, don't let anyone else hold the pen"

Ernest

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