hey guys, I have a 1990 3500 with a 454 tbi and am having some troubles with the timing. I have timed it correctly with unplugging the tan and black connector, setting it to 4 btdc and clearing code. After when i plug connector back in and start the truck i check the timing again and it is way out to lunch like 18 btdc at idle which is now 1500 - 1800 rpm.....as soon as i unplug the connector it will go back to 4 btdc. I am not to familiar with ignition components so that is why i come looking for any sort of help from you guys. Thanks

 

Does it ping when it goes to 18?

 

yes it does