i need some help!
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Joined: Jun 2008
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i need some help!
I have a 69 ford f-100 with a 302 engine. i'am having trouble with the truck backfiring and turning off. i replaced the ignition coil ,battery, voltage reg,alternader .the points are set at 17ths and the timing is set at 16degs to stay on .i need to know and understand whats going on .pls help!!!
Freshman User
Joined: Aug 2008
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My '69 had the same problem, it would pop like a cannon out the exhaust then die. The ignition switch was bad. Is it back-firing thru the intake or exhaust? I also had an old POS 360 that would pop thru the carburator and die sometimes. (I was building a 390 for the truck so I did'nt try to fix it) When I tore it down there was no nylon left on the top timing gear
I have no idea why it still ran.
I have no idea why it still ran.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
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From: Simi Valley, CA
If this truck has a Thermactor (smog) pump on it, there's an anti-back fire valve in the Thermactor system.
When that valve goes bad: POW! There goes the muffler. Scheiss! It just blew off!
That could and did happen.
When that valve goes bad: POW! There goes the muffler. Scheiss! It just blew off!
That could and did happen.
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Joined: Feb 2004
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From: topeka
I had an 87 trooper that would blow mufflers from backfirin'. Damn annoying that! Mechanic showed me which hose to disconnect to stop that. Just sayin.
There used to be talk of putting in a resistor somewhere to stop that diesel and run on but it was never clear where or how. A myth? But then again haven't heard about one doing the run on thing for a long time.
Isn't factory timing 8* BTDC? That always felt mushy to me. 16* sounds like a lot but i dunno. I never used a timing light.
Timing them by ear, we'd advance them till they had trouble starting then back it off bit by bit, till staring was no problem hot or cold.
Sorry, I don't have a real answer. I wonder if running cooler plugs would help.
Or increasing the octane of gas. I've got one of them orpan trucks, a 71 dodge with a 383 that doesn't even get along with reg.
As an after thought, that operahouseworks guy was one of those guys who was always impressive with his knowledge about all things electrical. Wonder if he'd make a stop in this thread.
Yeah, i'm gonna quit now.
Ford Parts Specialist
Joined: Nov 2006
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From: Simi Valley, CA
1969, some still used it.
Beginning in 1966, the T/E (Thermactor Emission) system was installed on all the cars and F100/250's. Even the HiPo Cobra Jets and Super Cobra Jets came with T/E.
Most 1968/72 F100/250's don't have T/E, excepting Econolines with 240/300/302's and F100's with 240's or 302's.
T/E went back on in 1973, and both the trucks and cars used T/E for for many years.
Beginning in 1966, the T/E (Thermactor Emission) system was installed on all the cars and F100/250's. Even the HiPo Cobra Jets and Super Cobra Jets came with T/E.
Most 1968/72 F100/250's don't have T/E, excepting Econolines with 240/300/302's and F100's with 240's or 302's.
T/E went back on in 1973, and both the trucks and cars used T/E for for many years.
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it does not have a smog pump. i also replaced the ing coil, and i checked the voltage and the voltage was 7.89 volts.is this normal? i also check the + side of the ing wire to see if it had short and it show countnutiy .
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From: Californicator
Check your vaccuume advance. Make shure it works. If it does
then you likly need a new timing chain and gears. That's what I loved about the 300 six shooter. No chain! The timing gears mesh together, And will
never wear out!
then you likly need a new timing chain and gears. That's what I loved about the 300 six shooter. No chain! The timing gears mesh together, And will
never wear out!
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From: topeka
Have you found a solution yet?
rig up a quick disconnect to the positive side of the coil. With the engine running disconnect the coil (key still on) and see if it *diesels* because it's hot.
I'd want to be looking at the ignition switch if i were you. pull it out of the dash, let it hang there. figure out which wire is the *run*wire. Pull it off the switch to see if doing so will kill the motor.
rig up a quick disconnect to the positive side of the coil. With the engine running disconnect the coil (key still on) and see if it *diesels* because it's hot.
I'd want to be looking at the ignition switch if i were you. pull it out of the dash, let it hang there. figure out which wire is the *run*wire. Pull it off the switch to see if doing so will kill the motor.
Lead Driver
Joined: Jan 2003
Posts: 9,893
Likes: 12
From: Ohio
Do you advance the timing each time it quits? They way you worded it, that is what it sounds like.
How many miles on it? Sounds like maybe a timing chain issue? Jumping a tooth? Either that or distributor gear sheared the pin and is slipping outta time.
How many miles on it? Sounds like maybe a timing chain issue? Jumping a tooth? Either that or distributor gear sheared the pin and is slipping outta time.
Fleet Mechanic
Joined: Dec 2006
Posts: 1,338
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From: UPSTATE NY
all i know is i replaced bad timing gears with the crummy plastic on it with some new heavy duty ones and its now night and day difference. the teeth were all cracked to hell and the chain had tons of slop in it. i love my truck now. oh and did i mention i have a phenolic carb spacer so down here in 95 degrees starting my truck is always chocolate cake.
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