Big block won't run (annoying)

Yeah, same car again. '75 duster with '76 400 big block, 727 auto trans,
older 8.75" rear. Thought I just about had it in running order but it has
recently developed a problem with either the fuel system or ignition
system i think and will not stay running. It started probably a few months
ago, only did it once in a while back then, now does it every time I try to
start it. The car will fire up and run good for a few minutes then starts
misfiring real bad then dies. Hard to start after that but will start then
dies again. I suspected the fuel system at first, so I wrapped the fuel
lines to make sure they weren't getting hot causing a vapor lock
situation. Also pulled the fuel line off the carb when she quit and liquid
fuel came out. Pump has good pressure, fuel filter is clean. The
distributor is new as of a year ago, and I replaced the coil and the
ballast resistor and the plugs and wires since the problem started and it
hasn't helped. The battery is new within the last year as well. The engine
has two ground straps, so I assume that is not the problem. The ignition
control module is not stock; it is an ancient GP Sorenson module on the
driver's side fender. I traced the wires to figure out where eveything is
going and checked for continuity through the module, the hot and ground
wires to the coil, the hot and ground wires to the pickup coil, and
through the coil itself. Everything checks out, but the problem persists.
I am out of ideas; can someone help me?

If you drop a little fuel straight into the carb, does it start immediately
then die?
How long does it run good before it craps out again?
How long do you have to wait before it will start and run good again?
What I'm getting at is, if it runs good for a time then craps out, something
could be marginal in the electrical system. When you pull current through
electronics they will heat up. When things heat up they expand. When they
expand they will separate.

I had a bunch of fuses in an old Datsun that worked for a few minutes. Then
they heated up after being used and the element between the end caps would
separate from one end (cold solder joint). After it separated the host unit
would stop working or work sluggishly. Also had an instrument cluster in my
daughter's car (2 of them) that had cold solder joints on the main board.
When the car was cold all was well. After some current flowed through the
system things would warm up and separate. I touched up all the solder
connections that looked suspicious (cracked) and all is still well. This
was a couple years back.

Heat (current flow) will cause things to expand and a connection will become
open or intermittent. After it cools down (no current flow) it will
contract and again make a good/better connection.


"sackattack84" > wrote in message
lkaboutautos.com...
> Yeah, same car again. '75 duster with '76 400 big block, 727 auto trans,
> older 8.75" rear. Thought I just about had it in running order but it has
> recently developed a problem with either the fuel system or ignition
> system i think and will not stay running. It started probably a few months
> ago, only did it once in a while back then, now does it every time I try
> to
> start it. The car will fire up and run good for a few minutes then starts
> misfiring real bad then dies. Hard to start after that but will start then
> dies again. I suspected the fuel system at first, so I wrapped the fuel
> lines to make sure they weren't getting hot causing a vapor lock
> situation. Also pulled the fuel line off the carb when she quit and liquid
> fuel came out. Pump has good pressure, fuel filter is clean. The
> distributor is new as of a year ago, and I replaced the coil and the
> ballast resistor and the plugs and wires since the problem started and it
> hasn't helped. The battery is new within the last year as well. The engine
> has two ground straps, so I assume that is not the problem. The ignition
> control module is not stock; it is an ancient GP Sorenson module on the
> driver's side fender. I traced the wires to figure out where eveything is
> going and checked for continuity through the module, the hot and ground
> wires to the coil, the hot and ground wires to the pickup coil, and
> through the coil itself. Everything checks out, but the problem persists.
> I am out of ideas; can someone help me?
>

Had something sounding familiar like this on my '79 Newport, 360, TQ. Had
one float intermittently sticking in the down position and wouldn't close
the needle valve.

Larry
Behold Beware Believe

"sackattack84" > wrote in message
lkaboutautos.com...
> Yeah, same car again. '75 duster with '76 400 big block, 727 auto trans,
> older 8.75" rear. Thought I just about had it in running order but it has
> recently developed a problem with either the fuel system or ignition
> system i think and will not stay running. It started probably a few months
> ago, only did it once in a while back then, now does it every time I try
> to
> start it. The car will fire up and run good for a few minutes then starts
> misfiring real bad then dies. Hard to start after that but will start then
> dies again. I suspected the fuel system at first, so I wrapped the fuel
> lines to make sure they weren't getting hot causing a vapor lock
> situation. Also pulled the fuel line off the carb when she quit and liquid
> fuel came out. Pump has good pressure, fuel filter is clean. The
> distributor is new as of a year ago, and I replaced the coil and the
> ballast resistor and the plugs and wires since the problem started and it
> hasn't helped. The battery is new within the last year as well. The engine
> has two ground straps, so I assume that is not the problem. The ignition
> control module is not stock; it is an ancient GP Sorenson module on the
> driver's side fender. I traced the wires to figure out where eveything is
> going and checked for continuity through the module, the hot and ground
> wires to the coil, the hot and ground wires to the pickup coil, and
> through the coil itself. Everything checks out, but the problem persists.
> I am out of ideas; can someone help me?
>



--
Posted via a free Usenet account from http://www.teranews.com

The car seems to be getting fuel, unless the pump is only working
intermittently? Pouring a little fuel in the carb does not really seem to
help. I checked the floats on the Holley carb and they are ok and set
correctly. The car will run for maybe 30 sec. to about a minute and a half
before it dies. Before it dies, it starts misfiring real bad. You can
really hear it through the exhaust, kind of an intermitant poofing sort of
noise coming from both pipes. I can usually restart it after a little
cranking, but it generally dies again right away or will turn over and
cough like it wants to start but won't. If it is caused by electrical
components, where should I start checking? The coil, distributor, plugs,
wires, ballast resistor, battery, and battery cables are all new. Could it
be a problem with the ignition module?

Have you tried feeding it fuel thruogh the carb throat? Starting fluid in a
spray can will let you know if its a fuel delivery problem or ignition. If
you can keep it running, I'd say you've got debris in the carb. I remeber
when alcohol was getting mixed to heavily into gas; that ate a lot of carbs
on the inside.

Was over trying to start the car yesterday. Could not even get it to start
now, keeps smelling like it is flooded but will not start. let it dry out
with the choke open for hours, still could not get it started and it
smelled like gas again. I can see fuel coming out of the venturis when I
open the throttle. I checked voltage from the coil to the distributor
while it was being cranked over and it is making good voltage. However, I
hooked the coil wire back up and pulled one of the spark plug wires off
the plug and touched one lead of the multimeter to the wire and another to
ground and got no voltage reading when the car was cranked over. I'm
assuming I should be reading an intermittent voltage spike, right? So I'm
thinking this means either the coil wire is bad, the cap and rotor are
bad, or the pickup coil is bad, right? This just seems funny since the
distributor, coil, plugs, and wires are all new. What do you guys think?

Not sure what sort of millimeter you are using but any that I've seen can't
measure that level of voltage (several thousand volts). You need to pull
out a plug, connect the plug wire to it, set the threaded part of the plug
on ground (head, exhaust, etc,). Then crank the engine and look for a blue
spark between the anode and the cathode of the plug (anode is the center
piece and cathode is the piece that curls over the center). If there is a
blue spark then you are getting spark to the plug. No spark - no ignition.
If you look at it in the dark it will be easier to see.

"sackattack84" > wrote in message
lkaboutautos.com...
> Was over trying to start the car yesterday. Could not even get it to start
> now, keeps smelling like it is flooded but will not start. let it dry out
> with the choke open for hours, still could not get it started and it
> smelled like gas again. I can see fuel coming out of the venturis when I
> open the throttle. I checked voltage from the coil to the distributor
> while it was being cranked over and it is making good voltage. However, I
> hooked the coil wire back up and pulled one of the spark plug wires off
> the plug and touched one lead of the multimeter to the wire and another to
> ground and got no voltage reading when the car was cranked over. I'm
> assuming I should be reading an intermittent voltage spike, right? So I'm
> thinking this means either the coil wire is bad, the cap and rotor are
> bad, or the pickup coil is bad, right? This just seems funny since the
> distributor, coil, plugs, and wires are all new. What do you guys think?
>

On Sun, 7 Jan 2007 17:45:59 -0600, "Abby Normal"
> wrote:

>Not sure what sort of millimeter you are using but any that I've seen can't
>measure that level of voltage (several thousand volts). You need to pull
>out a plug, connect the plug wire to it, set the threaded part of the plug
>on ground (head, exhaust, etc,). Then crank the engine and look for a blue
>spark between the anode and the cathode of the plug (anode is the center
>piece and cathode is the piece that curls over the center). If there is a
>blue spark then you are getting spark to the plug. No spark - no ignition.
>If you look at it in the dark it will be easier to see.
>
>"sackattack84" > wrote in message
alkaboutautos.com...
>> Was over trying to start the car yesterday. Could not even get it to start
>> now, keeps smelling like it is flooded but will not start. let it dry out
>> with the choke open for hours, still could not get it started and it
>> smelled like gas again. I can see fuel coming out of the venturis when I
>> open the throttle. I checked voltage from the coil to the distributor
>> while it was being cranked over and it is making good voltage. However, I
>> hooked the coil wire back up and pulled one of the spark plug wires off
>> the plug and touched one lead of the multimeter to the wire and another to
>> ground and got no voltage reading when the car was cranked over. I'm
>> assuming I should be reading an intermittent voltage spike, right? So I'm
>> thinking this means either the coil wire is bad, the cap and rotor are
>> bad, or the pickup coil is bad, right? This just seems funny since the
>> distributor, coil, plugs, and wires are all new. What do you guys think?
>>
>
Forget looking for spark - just grab the plug wire and crank <BG>.
You will know FOR SURE if you have a spark!!!


--
Posted via a free Usenet account from http://www.teranews.com

On Sun, 07 Jan 2007 17:27:27 -0500, "sackattack84"
> wrote:

>Was over trying to start the car yesterday. Could not even get it to start
>now, keeps smelling like it is flooded but will not start. let it dry out
>with the choke open for hours, still could not get it started and it
>smelled like gas again. I can see fuel coming out of the venturis when I
>open the throttle. I checked voltage from the coil to the distributor
>while it was being cranked over and it is making good voltage. However, I
>hooked the coil wire back up and pulled one of the spark plug wires off
>the plug and touched one lead of the multimeter to the wire and another to
>ground and got no voltage reading when the car was cranked over. I'm
>assuming I should be reading an intermittent voltage spike, right? So I'm
>thinking this means either the coil wire is bad, the cap and rotor are
>bad, or the pickup coil is bad, right? This just seems funny since the
>distributor, coil, plugs, and wires are all new. What do you guys think?

Electronic or coil ignition? Single or double ballast resistor if
electronic? Give me that information and I'll tell you how to
troubleshoot it. I suspect you have a dual balast electronic ignition
with a bad start resistor.

--
Posted via a free Usenet account from http://www.teranews.com

It is an electronic ignition with a dual ballast resistor. Looks to be a
pretty typical '75 A body system except for the GP sorenson ignition
module in place of the stock Chrysler unit. The multimeter that I have
will not measure the massive amount of voltage that the ignition system
puts out, but it shows intermittent readings all over the place from zero
to "infinity" (indicated simply by a 1 at the far left of the screen) when
hooked up to the coil with the engine cranking. Constant zero when hooked
to the plug wire.