300 starts without starter.
Elder User
Joined: Jan 2009
Posts: 774
Likes: 1
From: East Tennessee
Is this a joke? A guy telling us that the exhaust is really hot and that his engine starts without using the starter and the engine is completely shut down. It doesn't make sense AT ALL to me. Someone please explain.
Thread Starter
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Senior User
Joined: Feb 2008
Posts: 307
Likes: 0
After checking everything out I find that the heat riser valve is indeed working.
I also found that it wont start if it sits for over 2-3 seconds.
This engine has been running well for years without the emission conrol stuff, so why would it wait until now to start giving trouble?
The engine runs great other than this weird starting issue.
I also found that it wont start if it sits for over 2-3 seconds.
This engine has been running well for years without the emission conrol stuff, so why would it wait until now to start giving trouble?
The engine runs great other than this weird starting issue.
Posting Guru
Joined: Nov 2003
Posts: 1,006
Likes: 4
From: Sussex County, DE
What ignition system are you running? I know that some durasparks will spark once when you turn the key on (aftermarket ignition module). If you have a cylinder filled with a homogenous mixture and you spark it, it will kick the engine over. I know for a fact because I have seen it. I had a customer with a Ford Fairmont with a 200ci six that would sometimes do that shortly after shutdown. Sometimes it would sputter and quit again, but sometimes it would fire instantly without the starter, kind of like today's hybrids( although technically they have a starter generator, but you get the idea).
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
What ignition system are you running? I know that some durasparks will spark once when you turn the key on (aftermarket ignition module). If you have a cylinder filled with a homogenous mixture and you spark it, it will kick the engine over. I know for a fact because I have seen it. I had a customer with a Ford Fairmont with a 200ci six that would sometimes do that shortly after shutdown. Sometimes it would sputter and quit again, but sometimes it would fire instantly without the starter, kind of like today's hybrids( although technically they have a starter generator, but you get the idea).
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Well, now that I think about it, your motor has to actually be turning to fire the plugs with both systems. OR, somehow the motor is stopping with the veined armature lined up perfectly against the pickup module, and turning the key back on sparks it just once.
Posting Guru
Joined: Nov 2003
Posts: 1,006
Likes: 4
From: Sussex County, DE
On some aftermarket modules (GM HEI as well), if you put an ignition scope on the system and key it up, you will see the coil power up, then the ignition module shuts it off when it realizes that there is no engine speed (usually about a .25 second event). Cutting power to the coil causes the magnetic field to collapse, creating a spark. It then stays off until the engine is cranked and it gets an input. However, if the spark happens in a cylinder that is loaded with air/fuel and the piston is in a favorable location, the engine will fire during this event and start running. It is a weird thing, to be sure.
Cargo Master
Joined: Sep 2007
Posts: 2,095
Likes: 2
From: Wahpeton ND
I had this happen to me once after it was running. When I first installed my 300 it dieseled somthing terrible. The cause was bad timing and a high idle and I resolved that.
However I went to ace hardware one day and left the kids in the truck. Immediately after turning it off they ask to listin to the radio. So i turn the key forward and Pop, pop lurch. she starts driving forward in first. I figured she was just lined up with a loaded charge and bang.
only happend once scared the dickensout of us.
However I went to ace hardware one day and left the kids in the truck. Immediately after turning it off they ask to listin to the radio. So i turn the key forward and Pop, pop lurch. she starts driving forward in first. I figured she was just lined up with a loaded charge and bang.
only happend once scared the dickensout of us.
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Senior User
Joined: Oct 2004
Posts: 212
Likes: 0
From: Beaver, Ohio
my dads 85 300 will do it every now and then. it has to be perfect timing with gas in the camber and rotor button lined up perfect i guess. might be a compression issue that make one spot favorable for the motor to stop in for his to do it often
Posting Guru
Joined: Nov 2003
Posts: 1,006
Likes: 4
From: Sussex County, DE
Just shows you how much these old sixes want to run! EFI engines won't do that because when you kill the key, the fuel delivery stops, and the cylinders fill up with air only as the engine spins down. Carby engines draw fuel until they stop spinning.
Posting Guru
Joined: May 2007
Posts: 1,208
Likes: 2
From: North Reading Mass
A weird event that even has a name. Its called Starting on the Spark. On the real old cars there was a lever on the steering wheel for adjusting the spark advance. Sometimes on a warm engine you could advance or retard the lever producing a spark and if a cylinder was lined up right the engine would start.
Very handy in the days of hand cranking.
regards
rikard
Very handy in the days of hand cranking.
regards
rikard
Posting Guru
Joined: Nov 2003
Posts: 1,006
Likes: 4
From: Sussex County, DE
A weird event that even has a name. Its called Starting on the Spark. On the real old cars there was a lever on the steering wheel for adjusting the spark advance. Sometimes on a warm engine you could advance or retard the lever producing a spark and if a cylinder was lined up right the engine would start.
Very handy in the days of hand cranking.
regards
rikard
Very handy in the days of hand cranking.
regards
rikard
Elder User
Joined: Apr 2004
Posts: 970
Likes: 3
The fact that it doesn't start until you turn the key to the run position means it is creating a spark without having a trigger from the distributor. Since this is duraspark I would guess that warmed up it has a problem in the module causing this to happen. You are saving wear and tear on the starter. Will it cause other problems, seems to be a good question. kotzy
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
After checking everything out I find that the heat riser valve is indeed working.
I also found that it wont start if it sits for over 2-3 seconds.
This engine has been running well for years without the emission conrol stuff, so why would it wait until now to start giving trouble?
The engine runs great other than this weird starting issue.
I also found that it wont start if it sits for over 2-3 seconds.
This engine has been running well for years without the emission conrol stuff, so why would it wait until now to start giving trouble?
The engine runs great other than this weird starting issue.
Oh well, it was worth a check.
Easy to inspect.I agree that it must be something in your ignition somewhere. Another easy check is to bring your ignition module in. There's just about three bolts that hold it on from underneath in the fender well (I removed mine in the parking lot), and then unplug it. Most auto shops will check it for free. (If they don't, move on to the next one.)