Finally got Truck running again

[Lobo'74]

When we left off last episode . . .

Truck would not start. I pulled the spark plugs and 5 of the 8 were covered over with a black mess. No gap showing. Of the 5, 2 had a tannish coating over the top of the lack stuff.

Its no wonder Truck wouldn't start, I'm just glad he held off to quit till he was home.

I replaced the plugs, removing the passenger side header to do so. Used Bosch platinum (same as I took out). Still no start. No spark. Some of you said I shoulc check the wiring on the HEI and make sure it went to the unfused supply. It didn't. PO had tapped into a pink wire under the dash.

I saw that and also checked the fuses. One looked like it might be bad, the "Traffic Hazard". I tried to pull it out, broke it.

I tested for voltage at the HEI "batt" lug. Zero. I opened the 1967 Chassis service manual and started tracing wires. Hmmm. The fuse I broke was for . . . . YES, the "Traffic Hazard" circuit. Replaced the fuse, Truck started.

Next, I ran a connection between "Ign Unfused" and the "Batt" on the HEI. Disconnected the PO wiring to the pink wire. Again, no start. I bought a Chilton for 1980-1987 GM trucks. I figured my '79 350 was pretty much the same as an '80 (in terms of HEI). Thought it might be the ignition module, but no way to check it so I double checked all my connections. Now I DO have 13 vols at the HEI "Batt" lug. Truck starts, then quits and won't start again. At least I don't need to read Chilton's about replacing the ignition module . . .yet.

Leave it for a day.

Came back and tried again. Voltage comes and goes. From zero to 5 volts, to 13 volts. No pattern. The ground lead on my volt/ohm meter broke off. That explained the intermittent weird voltages. Went to radio shack and replaced the leads. Now its either 13 or zero.

I finally noticed that if I push the "Ign Unfused" lug (with the connector attached) UP it reads 13 volts. If I pull (even slightly) on the connection down towards the floor it goes to zero. So, I push it up, Truck starts and runs just super. I had not noticed how much less power it haad with the bad plugs. It has ALL KINDS of power now!

So, bad PO wiring, broken test leads, and an intermittent connection on the fuse block were the problems. Now all I have to do is take off the fuse block and clean it up get all the connections on it working all the time and I'm set.

Well, except for the fact that now my aftermarket, column mounted tack quit illuminating at night. That, and I have an RPM associated "tic-tic-tic" coming from the passenger side of the engine. I know the headers have a leak around there, is that what I'm hearing?

Thats probably going to be a whole new episode, so stay tuned!

[Jeepster376]

Thanks for sharing the news. and yes the ticking is probably the header, leaking at the head.

[FRENCHBLUE72]

Sound's like murphy's law was applied !!!!! Yep sound's like you have a headder leak no big deal just replace the gasket... I stepped up and used copper and have not had any exhaust leak's in about a year...

[Bowtie67]

Sounds like you might be the next runner up for a new wiring harness, Sometimes these old trucks and previous owners have and leave a few mysteries. Might be a good project for next winter if you can get by through the summer.

[Lobo'74]

Amen. No time for it now, but I see a Painless wiring harness in my future.