Series IIA Ignition Cut out?

[109sixer]

Been having a electrical Gremlin here. Replaced coil, dist, points/cond
etc...also checked fuel pump, carb, plugs. Replaced ignition switch and wiring.

The problem is strange...the ignition will just cut out...if I flip the
switch it will start up again..run for a while and cut out randomly.
I know it sounds like a short somewhere. I have been putting off
replacing the entire wiring harness for a while. I'm hoping there is
a easy fix here that someone may have run into before?

[B. Wallace]

I'm sure there's a thousand different possibilities, but I had a similar problem a while back. Mine's a SIII, but I discovered tha when I tapped the bottom of the steering column, where my fuse box is located, I could cause it to do the same thing. What I figured out was that one of the prongs that the fuse sits in was a little loose, and would cause the ignition to cut on and off while driving. I simply took the fuse out and crimped the prongs tighter with a needlenose plier.
It's sometimes the really simple things that can cause a major problem. Don't feel dumb if it is something like that, we've all been there and it took me a while to find my gremlin

[J!m]

Have you inspected the ignition switch itself (where the key goes in)? With age, these parts wear, and you could have an intermittent connection here. Turning the switch makes the connection, and then a bump comes along and rattles it loose on you...

Maybe check this before the harness ends up in the land fill.

[109sixer]

I've been told that SIIAs truck does'nt not have a fuse in the iginition circuit...
but I will check to see if someone has done some "custom wiring". Thanks
for the reply!

[109sixer]

Jim,

I have replaced the switch...the switch that was in there was a Kragen
special, so of course That was the first thing I threw out. The harness
is 37 years old and getting crunchy. I've heard of a place in Portland
that sells replacement harnesses for less than 200 bucks. It's called
the Hoffman Group. I'm thinking of ordering one of those for prevenative
maintenance. It would really suck to replace the harness and have the
problem not go away.

http://www.thehoffmangroup.com/KeepItClean/Products/Products_KICK.lasso

[Tim Smith]

Where is your ignition switch? Dashboard or the steering column?

If it's in the dash, then I would check the connections in the back. There is a lot of room for things to get pushed around back there though the years. You know, someone fixes a dash bulb but crammed all the wires back in there when reassembling the dash, causing too much stress on a connector for the ignition. Then one good bump, 10 years later and it comes loose and now you have a gremlin.

[Tim Smith]

Oh, just thought of a test you can do to check the ignition switch (and possibly remove the coil, dist, wires etc from the equation).

Turn on your heater blower on, or something else that works only when the ignition switch is on, and wait for the issue to show up again. When the engine fails then you will know it's the ignition switch if the blower fails too. If it doesn't then it might not be the switch but could be the wires further down the line.

Good luck!

[109sixer]

Tried the heater switch trick...the engine cuts out but the fan keeps going.
It seems to get worse when it has been running for a while ( Hot ).

By the way the power to the heater switch comes from the coil? This thing
is a mess!

[daveb]

not all heaters are wired to the ignition side. not a surefire test.

Tried the heater switch trick...the engine cuts out but the fan keeps going.
It seems to get worse when it has been running for a while ( Hot ).

By the way the power to the heater switch comes from the coil? This thing
is a mess!

[Tim Smith]

not all heaters are wired to the ignition side. not a surefire test.

True, true. Was hoping for something easy and forgot about that.

[109sixer]

OK...the heater is a Smiths flat heater ( Nice, works great ). The problem
began before the heater was installed. I've been behind the instrument
cluster more times than I'd like to admit. I believe the problem lies
somewhere in the power lead going from the harness to the coil +.

I've taken the Dist apart and re-soldered all the connections to make sure
there was no short inside the Dist. then I replaced the Low tension lead back to the coil etc...

My truck is a 1970 SIIA 109 NADA with Euro spec six cyl motor. It has
a Zenith Stromberg carb and the engine is out of a 78 with the smog
stuff taken off and capped.

Just more info to add to the soup!

[Tim Smith]

Tried the heater switch trick...the engine cuts out but the fan keeps going.
It seems to get worse when it has been running for a while ( Hot ).

By the way the power to the heater switch comes from the coil? This thing
is a mess!

So doesn't that mean that your coil is still getting power -> which means that your ignition switch is working?

I'm grabbing at straws. It's kind of tough to come up with a sure fire test without actually leaning under the hood. Although I'm sure the next poster will be able to do it.

[BackInA88]

Maybe try this?

I've had problems like this before on other vehicles.
I have in the past run a wire right from the battery to the coil to nail down which side of the circuit (engine or harness) the problem is on.

Question, I don't remember, is there a ballast resistor in the coil circuit?
These can tend to get flakey after the warm up when they are going bad.

[singingcamel]

next time you drive it and it cuts out ,check your coil. you may have a bad coil. heats up and then dies .i've seen this problem a few time.also check your coil wire and connections on your coil...
also agree with Mr. Smith on the connections on the back of your switch if its in the dash.
also when it cuts out ,move or wiggle the ignition switch to see if it helps
www.singingcamel.com

[109sixer]

I've tried both types of coils ... external and internal resistor.
I currently have a brand new Lucas gold coil with a built in resistor.
It's putting out 12 on the battery side and roughly 7 to the distributor.

I'm thinking it must be a fried ground wire in the harness. SIIa's
Have no fuses in the ignition so I could have very well burned out
a wire without knowing. Like they say..."the Smoke will come".