[raleigh]

So a few days ago the engine started acting up.

I was driving down the freeway and it just died, while driving. I pulled over and it fired right up, odd. It did it 2 more times on the way home.

I replaced the coil and the ignition module, they were both 10+ years old by the looks of them.

Well it did again today, but it didn't want to start back up. I may have flooded it just a little!

Got it started and drove home, it died once more on the way home and hesitated but didn't die one other time.

95% of the time it runs great, plenty of power and no hesitation at all.

Is it possible that I skipped a tooth or two on the timing gears? I would think that it would act up all the time if this was the case...

 

[69SCJ]

My opinion:
If it runs good when it is running it is not the timing.

Most likely a short somewhere. Something simple to check is to make sure the connectors at the coil are tight. The connectors in the slide on part loosen with time. You may have to pinch them slightly with pliers to tighten them up.

 

[79broncoowner]

Not the timing check the ignition switch,start it and reach up behind the switch and move the wires and see if it dies. The other thing is the pick up in the dist. but they usually just quit and wont restart

 

[KM81]

What you are describing has nothing to do with timing. Im not sure what it is, but its not timing

 

[raleigh]

Thanks for the reply, I only thought time because I had replaced all of the ignition parts in the last 2 months.

I know that my ignition switch needs replacing because it is a bit loose, but even when I wiggle the key it doesn't die.

I drove it around today for about 25 miles and had no issue, definitely electrical and intermittent.

 

[raleigh]

On my way to work this morning it started to backfire and would not run well if it was under load. I killed my O2 sensor so It was a strong misfire through the exhaust and also through the intake.

What besides timing could do that?

I decided to pull the timing cover and found a very loose chain, it hasn't skipped a tooth but I have about 3/4" of deflection. Would this be enough deflection to cause an issue like this?

I think all of the hesitations it had were actually backfires, and it only ever did it when I was accelerating or under a load.

 

[rossisnow]

I didnt know a 78 had an O2 sensor. All your vacuum lines good? The re-breather from my oil fill port kept coming loose from the back of the carb where it hardlines in. It would run rough, and when I pulled over it would die. Sounds similar, but yours sounds a little more drastic. Any fouled plugs or signs of unburned fuel?

 

[raleigh]

I didnt know a 78 had an O2 sensor. All your vacuum lines good? The re-breather from my oil fill port kept coming loose from the back of the carb where it hardlines in. It would run rough, and when I pulled over it would die. Sounds similar, but yours sounds a little more drastic. Any fouled plugs or signs of unburned fuel?

I have a Holley throttle body injection system on my truck, and I have minimal vacuum lines that are all in great shape.

I replaced the timing set today, it needed it badly.
Took it for a drive and it seems to respond better, set the timing at 17* (it seems to run best there.

I started at 11* and it ran rough, is 17* too high?

 

[justinp8]

this sounds exactly like the same problem I have been having for the last couple of weeks.

last night my beast turned off for the 5th time that day while doing about 60 on the highway at night time. after i jiggled the key, I found the issue is in the ignition switch somewhere.
planning to dig it out this week and clean up the bits I can, and replace the ones I cannot.

good luck!

 

[raleigh]

You're lucky about the ignition switch, I was thinking that was the issue until it start backfiring!

Gawd I hope the timing chain and setting the time does it. The engine runs much smoother and response is much better also.

 

[raleigh]

So here is the update on my particular issue.

Replaced the timing chain & gears, badly needed and the truck runs much better. Set the timing @ 14*.

However that was not the entire issue. I found that the negative side of the coil was grounding intermittendy.
This was from my tach lead, the insulaton on the wire had worn down.
I actually just found that today, it has been running great until this morning when it died on me.

So I think it is finally solved, I will update if anything else happens with it.