Baffled. New LED lights seem perfect when key is ON. Problems when I start the engine.

noahway13 said:

I added LED lights, turn signals, brake lights. -> https://www.amazon.com/dp/B07Y8B5PB9?ref=ppx_yo2ov_dt_b_product_details&th=1

1982 Honda cm250. They work perfect with just the key ON. Like when the headlight kicks in. But when I start the engine, they go bonkers, flash wrong, etc. When the engine gets turned off, they act fine again. I added a 2 pin electronic flasher relay. LF1-S-PIN 150 max. Amazon site->
https://www.amazon.com/dp/B073J82PNF?psc=1&ref=ppx_yo2ov_dt_b_product_details

I have checked and rechecked connections, wire colors, etc. I don't see why they work correctly until the engine turns over. Any ideas? I think maybe the relay works up to a point, and then can't keep up? IDK...

Click to expand...

Many reviews on Amazon about "hyperflashing" when engine running for that relay

My guess is that the higher voltage when engine running (over 13 volts) is too much for the relay to operate properly - a better quality (more expensive!) relay maybe the answer

I was thinking along the same lines of the increased voltage causing the problem.
Good call Nasher.

If you have a multimeter handy, set it to"a/c volts" and connect it to the battery with the engine running in case there's a leaky diode in the rectifier causing a/c pulses in the system.

mike in idaho said:

If you have a multimeter handy, set it to"a/c volts" and connect it to the battery with the engine running in case there's a leaky diode in the rectifier causing a/c pulses in the system.

Click to expand...

I'll go do that. I noticed before that the DC volts were close to 14 with engine running.

noahway13 said:

I'll go do that. I noticed before that the DC volts were close to 14 with engine running.

Click to expand...

noahway13 said:

I added LED lights, turn signals, brake lights. -> https://www.amazon.com/dp/B07Y8B5PB9?ref=ppx_yo2ov_dt_b_product_details&th=1

1982 Honda cm250. They work perfect with just the key ON. Like when the headlight kicks in. But when I start the engine, they go bonkers, flash wrong, etc. When the engine gets turned off, they act fine again. I added a 2 pin electronic flasher relay. LF1-S-PIN 150 max. Amazon site->
https://www.amazon.com/dp/B073J82PNF?psc=1&ref=ppx_yo2ov_dt_b_product_details

I have checked and rechecked connections, wire colors, etc. I don't see why they work correctly until the engine turns over. Any ideas? I think maybe the relay works up to a point, and then can't keep up? IDK...

Click to expand...

Well, I have tried the second, upgraded relay. same issue.
I have noticed that my dash "idiot" light is not blinking correctly. I don't know if that is a cause, or just part of the problem.
I tried to test AC on battery, but I had an Auto multimeter. It was only showing DC. Finally figured out how to isolate AC. It is showing some tiny microvolt twitches. I don't know how much would affect the system. It is very erratic. And there are some other issues...
HEY, could a leaky spark plug wire be affecting this? (Snap my fingers) That is not on until the motor turns over. Gonna run out and change that....