- Joined
- Aug 3, 2010
- Posts
- 29,214
- Reaction score
- 24,352
- Location
- Usually not in Ohio
- First Name
- Andy
- Truck Year
- '77, '78, '79, '84, '88
- Truck Model
- K5 thru K30
- Engine Size
- 350-454
Sometimes you can tell just by they way they are running, if you are familiar with that particular engine. But sometimes it's nearly impossible just by feel and sound. If you put a jumper wire across pins A and B in the diagnostic port (like checking codes) while the engine is running, the SES light will flash faster when in open loop.
