I want to make sure I did this right since this was my first time adjusting timing on a vehicle. Truck was reading about 18* advancement when warmed up at idle. It pinged occasionally at idle and when under load. So I picked up a timing light and with the spout connector disconnected retarded the timing at idle to about 11*. Truck seems to run better until I put the spout connector back in and the timing at idle went back up to 18-20*. Hadn't had the chance to test drive the truck yet, but was wondering if somewhere along the way I messed something up.


I made sure to tighten down the distributor, reconnect the spout, let the truck warm up.

 

With spout removed you are setting base timing. Stock is 10 degrees BTDC. Once you set that, the computer uses that as the reference point and will advance as necessary, so that's why you see it jump with the spout in.

 

It pinged occasionally at idle? That's a new one on me.

 

This caption explains how the ignition system works, and how to diagnose it:


(phone app link)

If you don't have a Haynes, it's time to get one:


(phone app link)

When you have one, read it cover-to-cover at least once.

 

Misfire maybe? When warmed up at idle it would occasionally "ping" hard enough to shake the entire truck.

That being said, the butt dyno says she's running better and revs without hesitation. Hopefully, she'll be more peppier when towing my trailer too. No more pinging under load either!