That wire is a feed for the ignition switch or fuse block in the cabin. A partial open on that circuit could certainly affect the trucks ability to start or stay running.

I probably should’ve clarified in my previous post to make sure the battery is disconnected before replacing those fusible links. Besides the risk of accidental grounding/arcing of the circuits, removing power from the ECM without first disconnecting the negative battery cable could possibly damage it.

GM didn’t say as much in those days, but for at least 10 years now they’ve issued a TSB annually to avoid module damage by making sure the battery is disconnected first.

 

I fixed that wire and adjusted timing to exactly 0 but still no start although close.. When it started timing was off maybe 3° and I had just finished putting new coolant temperature sensor on and plugged it in. The only 2 things I have done was adjust timing to 0° and adjust valve lash on #3 cylinder so I'm thinking of tightening valve lash like it was beforehand.

 

How are you adjusting the lash? The recommended spec is to tighten the adjusting nut until the pushrod won’t spin, then tighten one more full turn.

Here’s a screenshot of which valves to adjust and when. After the valves with #1 are adjusted, it should only take one full turn of the crankshaft to bring #4 to TDC.

You could also follow the firing order - it takes longer but allows you to adjust both valves on one cylinder at a time.

 

That is super helpful thanks. I was doing it like the Ellis machine shop YouTube video. After the adjustment you posted It was making more firing noise and also you could see smoke rising from iac hole after trying the start. So I took other valve cover off and adjusted them as well. Also put the distributor back to where it started which was 3° retarded or approximately. No start and it doesnt try to start like normal. So I am going to put them back best I can to where they started.

 

Today it wouldn't even roll over. I have 12.98 volts at battery tho and the connections at junction block same

 

Try jumping across the starter solenoid.

 

It has done that before where there is nothing whatsoever when turn key then it will roll over fine later

 

I'm thinking time to clean connections at starter as well. When I originally hooked up those orange wires many yrs ago I dont think battery was disconnected at all. It ran the other day so hope I can do it again.

 

I got it to roll over again its close to starting but I crawled under truck to see connections and there is a ground strap looking wire unhooked.

 

I'm pretty sure the left arrow is a ground strap and right arrow is a positive to battery