69 F 250 C/S Rebuilt 390 has spark no fire/ wont start...

Engine, ignition, fuel, cooling, exhaust

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SoCal250
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69 F 250 C/S Rebuilt 390 has spark no fire/ wont start...

Post by SoCal250 »

Hi all I have been working on my 69 F 250 C/S for about six months now I bought it form a guy and it broke down on me right after so i did not get to drive it more than 20 miles since i had it Mar 2016 , it sat for about a year then i started wrenching on it . I tried for the first time to start it and no Go
I thought there was no spark at first so i tested the coil for hot at the positive with volt meter key in run its at 6 volts in start mode its almost 12V but a little under the IGN on the relay reads same , i learned through threads this is a resitance wire lead i seen them joined at the ign pigtail under the dash and it goes to the thin red wire to coil positve the Big ? is what is a good reading on the negative side of the coil i get less than a volt in key on mode and almost 1V at start up ???? I know it has spark i took the cap off and cranked the motor and the points were sparking , also in one test i asked my son to hold the spark plug next to the block and at cranking he got shocked !!!!!! and dropped the plug wire lol :nono: . I might had cranked the motor a little more than i should had for a flat tappet break in but i primed the oil pump and using comp cam breakin oil only 5-6 seconds at a time .

I also put distributor in at TDC on number 1 turning the dist all the way to left and right it dont even bite no back fire no nothin ? I am guessing a weak spark I did cut and splice the red wire right after the fire wall to the positive coil it kept breaking on me due to age and wear but did not touch the pink wire side of the resistor wire I am a little stuck on why it did not even backfire ? primed float bowl gas coming into cylinders any help would be great ,Thanks .....
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colnago
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Re: 69 F 250 C/S Rebuilt 390 has spark no fire/ wont start...

Post by colnago »

These are pretty simple engines. The basics are fuel, air, spark. It sounds like you have spark down. Make sure the engine is on the compression stroke for #1 (use a remote starter or breaker bar on the crank), put the timing mark around 10 degrees BTDC, and make sure the distro rotor is pointing to the #1 terminal.

Next, check the fuel pump. Disconnect it from the carb, run the line into a bucket, and crank the engine. If you get fuel in the bucket, you're good. If you don't, the fuel pump is bad, or there's blockage in the line (very possible that rust/sediment from the tank got picked up, and is blocking the line or filter).

Next check the carb. You said you primed it. How far out are the idle screws? Carefully snug them down (do not crank on them; be gentle), then turn them out 1-1/2 turns. It's easiest to get to the screws if you remove the air filter. Check the accelerator pump; look down the carb, and "stab" the throttle linkage. You should see a stream of gas squirt into the carb throat. If not, you might need to rebuild the carb.

These are basic starter things to check. From your description, I'm suspecting the carb. Keep us posted.

Joseph
"Sugar", my 1967 Ford F250 2WD Camper Special, 352FE, Ford iron "T" Intake with 1405 Edelbrock, Duraspark II Ignition, C6 transmission, front disc brake conversion.
SoCal250
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Re: 69 F 250 C/S Rebuilt 390 has spark no fire/ wont start...

Post by SoCal250 »

Update .... I was not patient and let common sense fly in the wind it's been a long time waiting to start the motor and I just lost my patience , it is a rebuilt 390 and C/6 auto I'm running comp 265 dual energy cam and 1 " alum riser to a new Holly 500 cfm . I was able to get it started funny thing my old fomoco voltage regulator mechanical type I suspected was no good I replaced it with a electronic type at least that's what they sold me when I asked for one you don't hear the click when you turn the key . It fired right up after I installed it I had spark but very weak spark not enough to fire the engine as far as the simple steps like turning it to 10 btdc and dropping the dist in at #1 just dropped it in at #1 so when I broke in my cam my timing was way off ran like crap it was around 30 degrees before TDC for 20 min , also it got hot not overheated but in the 200 210/215 and I said that's enough for 20 min . Today I had my son crank the engine and got it lined up with 10 btdc so it ran for 5 min as I attempted to ajust the carb and I shut it off would not start again doesn't look like it pumping fuel , the bucket to carb bucket as a fuel tank all these things I need to try funny after the 20 min break cam break in I shut it off and the gas was bieng sucked like a vacuum either from the tank or the fuel pump out of the filter and it sucked it dry just left the filter lol .... I'm supecting the cab tank has a leak or crack in the hard line to tank inside or something .......
SoCal250
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Re: 69 F 250 C/S Rebuilt 390 has spark no fire/ wont start...

Post by SoCal250 »

Also I don't know what happened to the resistance wire but before I changed the VR I had around 6 volts in key on mode and 11 or so in start mode on the positive side of coil and only 0.5 v on negative key on mode and 1v negative side at start mode new VR has battery voltage in key on mode on both ??? That's all I changed was the VR and the 2 fuses one goes to alternator one to VR in the engine bay schematic shows 4 amp there were 2 amps in there there is a third higher up in bay left side near the 3 connectors by fore wall the red /yellow and black quick connector previous owner has a 20 amp
I did not see it on the diagram but it looks like a factory fuse holder must go to starter relay or something maybe a/c ??? I put the pertronix back in since I was getting 12 v at key on now but don't know if that will try my coil ? 1.5 ohm flamethrower .
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