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Discussion Starter #1 (Edited)
First of all, I want to thank all of you for your help, your time and effort. You guys have helped me so much throughout my Goldwing ownership. You guys Rock! I don’t recall all the usernames that has contributed to helping me but you guys are an amazing bunch of guys and I am grateful to have the ability to reach out and get a professional response. Rednax (I think) has gone over and above to help me many times!

Now...:

Not more than 2k miles ago I had replaced the TPS due to a direct short signal received by the onboard computer. Modified one of those ‘88 Acura sensors to work and she ran beautifully. Not so good now.

I accidentally left her out in the rain uncovered just recently and since then she’s been acting up.

First I had to adjust the idle because it was a little low on startup. On the next couple (short) rides she began to run worse.

She starts up good but if I touch the throttle, she dies. It’ll rev up fine but won’t stay running after throttle up unless I’m holding a constant 2k plus rpm and even then she spits and sputters.

After warming up she ran better but now she’s running even worse after warming up.

There are no fault lights on. I’ve removed the plugs, cleaned and inspected to find a really rich mixture (black suet) on all 4 and reinstalled.

I’m thinking either the TPS is out of range, there’s water in the vacuum system, bad fuel (after 3-4 tanks still), overfilled moisture collector, vacuum leak (causing all 4 to be rich?), fuel pump (or filter) or bad injectors (again, all 4?).

 

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Because you just worked on the throttle position sensor I would start there. I would expect a steady voltage change as you slowly rotate the throttle with no irregularities. Nice and steady.
The next thing I would look at is the pressure sensors. PBl and PBr. I would expect the right side and left side voltages to be very similar. If you see an issue do not automatically think sensor. It could be a vacuum leak that the sensor is repoting accurately.
 

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Acting up after sitting out in the rain indicates an electrical problem, most likely the ignition system. Have you done any work on the coils or plug wires and caps?
 
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Discussion Starter #4
Well, it looks like the TPS went wonky again. RedWing52, the readings were erratic. From 0.56vdc to 0.87vdc

 

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Discussion Starter #5
So, I reset the TPS to 0.5vdc (now reading 0.485vdc). Ops checks good!! I am going to buy another TPS just in case...


 

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you have learned more than you wanted to know, but with the new knowledge comes confidence.
 

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Enjoyed your write up. The TPS is a critical item in the system and an item that has the least amount of QA/QC, same in the auto industry. Had this happen to me with an '85 Limited Edition that I put on the road after some 4 years in a fellows back yard. New TPS like yours and had nothing but grief. Changed it out and the new part worked well. Still looking for a good alternative for the '85 I still have.

How have you got the internal TPS arm connected to the throttle shaft?

Well done on the troubleshooting.
 
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Nice job, did the same and had to modify the connection to fit the external alt mod. Not a lot of room in there with an external alternator. Picture of the final product shows a broken off arm, have a few of these as spares. Still using the OEM TPS.
TPS Arm Mod 2.jpg
TPS Mod for alt mod install.jpg
 
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Discussion Starter #12
How are you using the OEM TPS? My OEM TPS bit the dust. The readings were bouncing all over the place. I believe water got into it somehow and caused a short which caused it to overheat.

Built a harness using connectors instead.
323187
 

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You mention in your video with the engine running that the Fuel System dash light is still on. Why this light is called "Fuel System" is a mystery because it is more a check CFI system/engine light, can be misleading. This indicates that the TPS is out of range. There should be an error code on the ECU confirming this. If the TPS was in spec there should be no error code and the Fuel System dash light would be off.

To set the TPS you need to splice into the TPS wiring so you can measure the voltage. I installed permanent wires for this and have them under the shelter by the fuse block so I don't have to disconnect any other wiring. You have to bring the throttle stop screw that is at the rear of the throttle shaft on the left side up to the throttle arm and insert a 2.9 mm (0.11") spacer between the throttle arm and throttle stop screw. Set the TPS so that the output voltage is 0.475 to 0.495 VDC. When this is set, the Fuel System dash light should be off, and no error code on the ECU. Back off the throttle stop screw and change leads such that you have a TPS voltage range of 0 to 5 VDC or thereabout.

Looking at the voltage with the engine running is no indication of what the TPS is actually doing.

A faulty TPS is generally because of age and the fact that most of us ride within a certain range and the TPS gets worn in that specific area. The faulty aftermarket new TPS that I had to deal with was faulty in the 1800 to 3500 range. Engine operated well below 1800 and over 3500. No error code was generated because it was set properly. The engine would misfire quite often and the misfire was so sever it felt like the wrong cylinder would fire and almost stop the engine. This problem got worse as the engine got hotter. Heat does affect the TPS. Didn't mind travelling over 3500 RPM, but it was not pleasant when I had to slow down. Didn't believe that it was the TPS because it was new, but it was faulty.

Getting back to your question of the OEM TPS. It's still working well, but it won't last forever. Looking for a suitable alternative as I have mentioned - have used the aftermarket Honda TPS as a trial. Tested different ways to get the TPS arm hooked into the throttle shaft. Long term research project you might say. I browse the parts on eBay and such and hope that a NOS shows up.

The TPS and ECU are the two items that I am actively looking for a suitable replacement. Intend to pick up a used working ECU in the near future as a spare. Have identified suitable replacements for the other sensors in the system.
 
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I have just been reading the TPS calibration section of the supplement. Here is the procedure as per the supplement:

"With the ignition switch on, measure the output voltage between the white (+) and green (-) adapter leads while gradually opening the throttle. Replace the sensor if the voltage does not rise smoothly as the throttle is opened.

Loosen the idle adjustment screw and insert a 2.9 mm (0.11”) gauge between the throttle arm and throttle stop screw.

Set the tester in the 2V range and measure the voltage with the inspection gauge left in place. Output voltage: 0.475- 0.495 V

NOTES:

• Do not loosen the stop screw lock nut.
• Use only a 2.9 mm (0.11”) inspection gauge."
 
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I've been using this procedure for the past however many times I calibrated the TPS, but the "Loosen the idle adjustment screw and insert a 2.9 mm (0.11”) gauge between the throttle arm and throttle stop screw." is intriguing me. I have always brought the throttle stop screw up to the throttle arm, instead of lowering the throttle arm to the throttle stop screw. Have been able to set the TPS to the correct voltage range, and have no error codes, but wonder if setting the TPS by raising the throttle stop screw to the throttle arm throws the fuel system off - too much fuel being injected and the idle is off especially when engine is cold and first started. When I get finished with rebuilding my 1200 engine, I will try calibrating the TPS by loosening off the idle adjustment screw.
 
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I've been using this procedure for the past however many times I calibrated the TPS, but the "Loosen the idle adjustment screw and insert a 2.9 mm (0.11”) gauge between the throttle arm and throttle stop screw." is intriguing me. I have always brought the throttle stop screw up to the throttle arm, instead of lowering the throttle arm to the throttle stop screw. Have been able to set the TPS to the correct voltage range, and have no error codes, but wonder if setting the TPS by raising the throttle stop screw to the throttle arm throws the fuel system off - too much fuel being injected and the idle is off especially when engine is cold and first started. When I get finished with rebuilding my 1200 engine, I will try calibrating the TPS by loosening off the idle adjustment screw.
The throttle stop screw is supposed to be set at assembly and not ever adjusted so the 2.9mm gauge sets the throttle at an exact position for making the adjustment.
 

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Discussion Starter #18
You guys are awesome!! I really appreciate all your help so much!!
 

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The throttle stop screw is supposed to be set at assembly and not ever adjusted so the 2.9mm gauge sets the throttle at an exact position for making the adjustment.
Will be looking for the setting. Thanks
 

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Discussion Starter #20
323305
Had to put a new TPS on. The other one was too erratic. Bought 2 more and modified them to fit. Looks like I’ll have to either make an investment in a quality TPS that will work or keep buying these cheap Honda ones.
 
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