I recently have been having this problem where my truck will drive for a
while and die at the worst time like an intersection or miles from anyone. I
thought it was the power cables hooked to the battery for the MSD ignition
when this first started happening I replaced the connections and it didn't
happen for a while. Then I was driving along and at a intersection the truck
died and I tried to start it, it would just turn over until the battery was
dead. I checked the spark plug wire for a spark and there was nothing. I got
it to start again after a while and then it just stalled out once again this
time I was still in the parking lot of a store so that was good. I removed
the after market ignition stuff and plugged the old HEI stuff into the
distributor and it still didn't have a spark so since its been a while since
tuned it up I did a full tune up that included; spark plugs, cap, rotor,
wires, coil, oil, oil filter and air filter. After I did all this I tried to
take it out for a test drive and it only ran for about ten minutes in the
yard before I took it out. It got across the street before it died out again
with no spark. I thought it might be a the HEI ignition module so I took
that off and went to auto zone and they tested it. There was a row of red
lights on the top that went to green as it was tested. When since my truck
wasn't doing the stalling out thing right then I ask them to test it a
couple of time until it got warm. It kept working after ten try's like it
should and then one light (the dwell light) stayed red. Then he tested it a
couple more times and it worked again like it was meant to. I decided to
change that as well just to be sure. I thought that after all this I would
have it working properly again so I took it out and it stalled just like its
been doing. There is no spark going to the spark plugs. There is gas and it
does turn over. I am out of ideas though. I need alittle help to track this
problem down. And some diagnosing help also.
Thanks in advance, D.L. Man
P.S. Sorry for talking you ear off.
When you get a no-start, check the postive lead from the IGN switch to the
ignition coil/HEI module (fat red wire). It should have +12V with key to
run and while cranking. If it don't, you either have a shorted wire or a
bad IGN switch.
Doesn't the ignition lead go through the starter before it goes to the coil?
Is that the one that I should check? I have been having some trouble with
the starter not starting like it should. I have turned the key on and it
just clicked. I would try it again and sometimes it would work. It hasn't
been that annoying to get me down there to look though. The problem with the
starter has been going on long before the engine stalls.
I will check that ASAP. Thanks. If you have any more suggestions after I fix
that would be helpful. The magnetic pickup is something I haven't looked at
could that be a problem?
Not through the starter, but there is a lead from the IGN switch to the
starter solenoid. The IGN switch has a lead to the solenoid and a seperate
lead for the coil.
You want to check the lead to the coil that runs from the IGN switch. The
starter solenoid lead obviously works fine as it will crank but won't start.
If this is the stock distributor cap and stock plug on the end of the coil
positive, pay close attention to the connection between the lead wire and
the plug it terminates into. It (the plug) has a tendency to loosen and
while it might test fine, as soon as you plug er' in it wiggles loose and no
juice to the coil.
Bad or dirty batter connections most likely.
If you are talking about the inductive pickup coil, yes it could be the
problem. Test for voltage to the coil first, check the coil next, and if
both check ok it might be the pickup coil.
I didn't think it does but where does those wires go that plug into the
And what is that plug that goes into the carburetor? One wire goes to the
thermostat and into the carb and then into the wires near the distributor.
Aren't those computer controlled or am I wrong. Do you know what those wires
There is a harness that comes out from the firewall(I think) and then it
goes into dist. It has 4 or five wires on it and they all go into a plug.
the only other wire that plugs into the dist is the battery wire but that is
on the other side of the dist.
Its a 2 prong plug that is located on top the carb near to where the gas
line comes in.
I think this was just a "what does that do and why can't I put a holly carb
in its place, because of it question"
I have tried that and it did have voltage to it. I haven't been able to test
it when the car dies because I was out away from the tester. I think that
was the problem too. However, the first night that this happened to me I
still had the MSD ignition hooked up and my friend was helping me crank the
car over. They left the ignition on in the car and I crossed the battery
plug with the ground (at the distributor) and fried the battery line going
the MSD ignition. Meanwhile the car still wouldn't start even though at that
time there was power to that wire at least. After I hooked up the old plug
into the dist. I did set up a switch with 12 volt power in case it does die
again I can flip the switch and add 12 volts to that line. If it does start
up after that I know that the power to that wire is stopping.
"Of sorts" being the key term. I'd hardly consider it a computer as it
doesn't control anything but spark..............
Would you consider an MSD or Mallory ignition system "computerized?" Not
What does the ESC do? Where is that located? Someone told me that the
computer would heat up and stop sparking. But once it cooled down the car
would start again. that is similar to is happening with me. If there is a
computer "of sorts" that connects to dist then that is the last thing that I
haven't checked. I did like doc said and I followed the switched wire from
the dist down to a wire harness that was on the firewall. And from there I
followed it into the cab. As far up as the switch attached to the column.
But the wire seemed fine and there was power to it into the switch. If it
goes out later I will test that wire again to see for sure.
It controls the ignition timing based upon signals received from
the knock sensor. IOWs it's a spark retard control.
Above the glove box.
Silver box, slightly smaller than a cigar box.
More or less true...
The ESC module intercepts the signal from the pole piece in the
distributor, the signal is sent to a buffer and outputted back to
the ignition control module to fire the coil.
From your other posts you've found the 4 wire connector coming
out of the distributor to the firewall (goes from there to the
ESC module) disconnect the 4 wire connector and on the side of
that 4 wire connector that is attached to the distributor, jumper
the green wire to the black wire, this will by-pass the ESC
module, if the engine now runs, you've found the problem.
If this fixes it, you'll want to make a more permanent repair by
cutting and soldering the green wire to the black, you can do
this either at the 4 wire connector or, plug the 4 wire back
together and cut and solder the green to black right at the ESC
module harness under the dash. The ESC module does not need to
be plugged in once this is done.
There is/was actually a TSB on this procedure back in the mid 80s
authorizing it, reset the ignition timing to zero degrees from
the OE spec of 6 degrees.
Thanks for your help. It hasn't died since I checked the wiring to the ECS
and to the ignition switch. There was a power wire that was spliced into the
bat line of the dist. I simply spread the insulation apart more and spread
the wires apart and threaded the other wire through it like a needle and
rapped in around its self. I guess that was the problem. The wire to the ECS
was loosing contact and dyeing. I am curious what you meant by resetting the
timing to 0 and the OE spec of 6 degrees?
Thanks goes out to Doc too. You helped allot with me tracking this little
I did like was suggested and removed the ecs module from the dist. Its weird
now but I seem to have more power. I think that the module was retarding my
ignition to much and to often. It seems to have a new lease on life(my
truck). Since it wasn't the MSD ignition that was going out and affecting my
truck I was wonder if I should hook it back up? The truck died on my when I
had the regular ignition hooked up. And it died after I traced a wire that
was loose. Both times the MSD ignition module wasn't hooked up. I think that
it would be safe to reinstall it. I did notice that while it was hooked up
it kept my spark plugs cleaner. The old ignition wasn't that great at
sending a full spark because the spark plugs were always covered in carbon.
I can't wait to see what it does now that the dist doesn't retard the
ignition to much.
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