engine quit, wont start
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Senior User
Joined: Apr 2003
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From: Northeast OH
engine quit, wont start
for a while my '78 F250 400 was running rough when i gave it gas, but smooth at idle and at light throttle. then i was driving , in passing gear, and the engine shut off just as if i had turned off the key. the tranny was still spinning the engine as i coasted but it would not restart. it did let off a very loud backfire though before i threw it in neutral. now the truck will not start even on starting fluid.
any ideas? timing chain?
any ideas? timing chain?
i ain't rite
Joined: Mar 2005
Posts: 65,548
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From: Marlboro Mental Hospital.
sounds like a bad coil. they will idle fine, but break up when hot, then finally just die. been there, done that with the 65 falcon, the 66 7 litre, and the 79 f250.
all three fired rite up after replacing the coil, and the running miss went away.
all three fired rite up after replacing the coil, and the running miss went away.
New User
Joined: Jan 2008
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How many on miles on the engine ?
If it's a high miler, you need to check for timing chain slop.
What happened to you is what happens when it finally breaks a couple of cogs off.
Do the timing chain slop test with the distributor cap off & a breaker bar & socket for the crankshaft.
If it's a high miler, you need to check for timing chain slop.
What happened to you is what happens when it finally breaks a couple of cogs off.
Do the timing chain slop test with the distributor cap off & a breaker bar & socket for the crankshaft.
Elder User
Joined: Dec 2004
Posts: 675
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From: Springfield, OR
Maybe your engine control unit(ECU) or your pickup coil in the distributor went South. Seems like your not getting any spark. If you have a timing light hook it up to #1 lead and see if it flashes while someone cranks the truck over, or if you dont have a timing light then pull a plug and ground it to the block and crank the engine-check for spark.
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Senior User
Joined: Apr 2003
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From: Northeast OH
i do have an aftermarket tach on the steering column. i'll check the wire going to it, it has worked intermittently so there may be a problem there.
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Thread Starter
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Senior User
Joined: Apr 2003
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From: Northeast OH
Ok I put a new coil in it and still no go. i hooked up my timing light and it did not flash when cranking.
this truck has a ballast resistor on the driver's side fenderwell. is this stock ot was it added by a previous owner? if it's stock should i try changint it? if it's not stock should i eliminate it? where else should i be looking?
this truck has a ballast resistor on the driver's side fenderwell. is this stock ot was it added by a previous owner? if it's stock should i try changint it? if it's not stock should i eliminate it? where else should i be looking?
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Postmaster
Joined: Feb 2003
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First I would pull the distributor cap and be sure the rotor is turning when you crank it. If not the distributor gear roll pin could have sheared.
If the rotor is turning I would check voltage at the coil. If the coil has 12v at the postive terminal, try changing the ignition amplifier (silver box on the drivers fender).
The problem definitely sounds electrical. Let us know what yuo find.
If the rotor is turning I would check voltage at the coil. If the coil has 12v at the postive terminal, try changing the ignition amplifier (silver box on the drivers fender).
The problem definitely sounds electrical. Let us know what yuo find.
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69Oiler, it's either a broken timing chain, or a sheared roll pin holding the distributor gear on. I'd pull the distributor and check the gear pin, since that's the weaker point, and a common problem with the 351M/400.....
Postmaster
Joined: Feb 2003
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The timing chain is probably good. Might be stretched but probably still operational relative to this problem.
The common scenario in this type of failure is something gets in the oil pump. The pump had tight clearances so it doesn't have to be much. I could be just a skin of varnish that has collected in the pickup tube over the years. The oil pump jambs and either the drive shaft breaks or the roll pin in the distributor shears. Since your dizzy isn't turning, I'd bet on the roll pin. Believe it or not, this is a good thing. If the roll pin didn't shear, the oil pump drive could have and the engine would have continued to run with no oil pressure. Do not be tempted to 'improve' the roll pin by doubling it up or replacing it with a solid pin.
You will have to pull the dizzy to replace the pin. Be carefull to not drop the oil pump drive into the bottom of the pan. You might want to consider dropping the oil pan and replacing the oil pump and pickup tube. If there's still crap in the system, it could sieze again.
The common scenario in this type of failure is something gets in the oil pump. The pump had tight clearances so it doesn't have to be much. I could be just a skin of varnish that has collected in the pickup tube over the years. The oil pump jambs and either the drive shaft breaks or the roll pin in the distributor shears. Since your dizzy isn't turning, I'd bet on the roll pin. Believe it or not, this is a good thing. If the roll pin didn't shear, the oil pump drive could have and the engine would have continued to run with no oil pressure. Do not be tempted to 'improve' the roll pin by doubling it up or replacing it with a solid pin.
You will have to pull the dizzy to replace the pin. Be carefull to not drop the oil pump drive into the bottom of the pan. You might want to consider dropping the oil pan and replacing the oil pump and pickup tube. If there's still crap in the system, it could sieze again.
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Senior User
Joined: Apr 2003
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From: Northeast OH
dizzy gear crunched
finally got out there and pulled the distributor, the gear is split open and missing a couple teeth. did my oil pump sieze? i plan on pulling the oil pan and replacing the oil pump and the distributor gear. am i on the right track? anything else i should replace while i'm there? besides bearings, that aint gonna happen.
Senior User
Joined: Dec 2001
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From: b.c. canada
Originally Posted by 69oiler
finally got out there and pulled the distributor, the gear is split open and missing a couple teeth. did my oil pump sieze? i plan on pulling the oil pan and replacing the oil pump and the distributor gear. am i on the right track? anything else i should replace while i'm there? besides bearings, that aint gonna happen.
This happened on my 70 mustang 351w, it was a performance orianted engine. what happend to me was the distributer itself siezed up and stripped out the distributer gear and the cam gear asswell, i had to replace the cam along with the distributer.
see of the distributer turns freely in your hand, take the shaft push it towards and away from the cap and turn it to see if binds or looks bent. My distributer felt good the first time i spun it but after a little but of tinkering it bound up.
look down the distributer hole while you turn the engine by hand and see if theres any scares on the cam gear gear. if there is then you have to replace the cam and of course new lifters with a new cam.
You can check to see if the oil pump is siezed by using a 5/16 inch deep socket with a 1/4 drive extension and ratchet. make sure you tape the socket to the extension as to not drop it in the pan. i think its a 5/16 inch socket you use maybe bigger. just check on that one.
if the cam isnt spinning as you turn the engine over then your problems are further down, possibly timing chain. Do the 400,s have a timing gear sheer pin?
-gbm-