My car is negative ground. I am using the E10 Superstar led as the ignition light bulb. No problem. I turn the key to the on position, with out starting the car, the Superstar led lights up the red ignition and stays lit. When I start the car, the led will fade out, when the car gets up to idle speed.
Here is a photo of the led and a link to where you can purchase it.
1449 E10
https://autolumination.com/otherleds.htm
If the above does not work for you, then you have a problem somewhere. I'll try and help you fix it, as I'm sure others here will also.
Cheers,
Roger