Have an '85 Limited that I have been refurbishing for three and 1/2 years now, do work then ride, repeat as necessary. Once these FI bikes are working well, great bikes.
First thing I would do is set the idle and calibrate the TPS. Next I would suggest balancing the right/left cylinder banks. The idle will be affected so it's a dual calibration.
The vacuum lines go from each cylinder bank up to the PB sensors (MAP). I would put a vacuum gauge on each side and check the vacuum. If the system is working correctly you will draw a good vacuum. The reed valves work quite well and draw a lot of air from the idle air control system for cold starts, and to provide a source of air for the cylinders when the throttle is shut fully such as when decelerating.
If you disconnect one PB sensor vacuum line at a time, there will be no change in the engine operation. Disconnect both at the same time and there will be an issue. The ECU uses the PB sensor signal to assist in engine idle and engine performance below approximately 3000 RPM.
If you don't have the service manuals for your bike, would recommend getting a copy.
Troubleshooting these older FI bikes without the manuals is not an easy task.
No error codes is good. The injectors on these FI bikes are quite robust. Had mine cleaned and flow tested a while back, before cleaning flowed at 64 CC/min, after cleaning 66 cc/min. Shouldn't need to run seafoam or other products through the injectors.
The fuel system light, if it comes on is the equivalent of a check engine light. Had this light come on on another '85 LTD that I put on the road and have subsequently sold. Thought it was the fuel system, but there is nothing on the fuel system to trigger this warning light. Did some other tests such as leaving the air temp sensor disconnected, and took the TPS out of calibration, fuel system light came on.
Best of luck. Cheers
I don’t have a service manual besides the Haynes manual from amazon.
I don’t know where the TPS is. I looked for it.
I got rid of my alluminum wings and picked up a Goldwing. Here to be a Light.