any ford guys here???

[Stevie-D]

i've got a 78 thunderbird that i'm restoring. it's got a 351W mated to a C4. it's been sitting down in my barn for a good 10 years now. motor ran when we put it in the barn. now fast forward 10 years...
pulled it into the garage, cranked it over a few times...no spark whatsoever. got out the test light, had power to the coil, nothing out of it. bought a new coil, same deal. :huh now i'll admit im not the brightest crayon in the box, but it seems to me that if i have power to + and - on the coil, shouldn't i be getting power out of the coil????

i've got a stock wiring diagram, but it's a pain in the arse to read. can anyone steer me in the right direction to get some spark out of this beast?

[250rAL]

Sounds like you need a shop manual. Otherwise try here:

http://forums.tccoa.com/

[aint skeard]

if it has points clean them.

[Out_Sider]

Check your distributor

[Butters]

Ford is good.

[hondaracer2001]

what i would do...i would make sure all the wires coming out are good...if its been sitting for 10 years who knows what has chewed on them or anything....check everything..

[WhiteBros400ex]

I love Fords.

If i where you like someone else said check the distributer(sp) and maybe put in a new one and new plugs and wires.Also check all your wires make sure none are chewed like someone else also said.

[nat3060]

ford girl right here

my truck:

http://fordtruckworld.tenmagazines.com/mygallery.ten?id=14911

[PHAT400]

Battery to coil, coil to distributor, distributor to plug wires, plug wires to plugs.

If you have replaced the coil then the next likely culprit is the distributor. Get all new gut's and rebuild it. After 10 years it's probably crap.

Good luck..

[PHAT400]

Originally posted by PHAT400
Battery to coil, coil to distributor, distributor to plug wires, plug wires to plugs.

If you have replaced the coil then the next likely culprit is the distributor. Get all new gut's and rebuild it. After 10 years it's probably crap.

Good luck..

Sorry, starter and solenoid are in there also but it sound's like you have a spark issue not a starter issue.

;)

[wilkin250r]

Originally posted by Stevie-D
:huh now i'll admit im not the brightest crayon in the box, but it seems to me that if i have power to + and - on the coil, shouldn't i be getting power out of the coil????

Not necessarily.

Most of my knowledge of ignition systems comes from my background in electrical engineering. While I know the theory and how they work, I'm not a mechanic, so I don't know the exact style that you have on your thunderbird.

On older point-style ignitions, the coil has a large electrical current flowing through the primary side of the coil, the current comes directly from the battery. This creates a huge magnetic field within the coil. When it came time for the spark plug to fire, the points would stop that huge current, cut it clean off. This caused that large magnetic field to collapse very quickly, and this collapsing magnetic field creates a huge voltage on the secondary side of the coil. The secondary side was fed directly to the spark plug, or with multi-cylinder engines, fed through the distributor to the spark plug.

So, just because you have power in to the coil doesn't necessarily mean you'll have power out of it. If your points and/or distributor aren't working correctly, you won't be getting anything on the output side.

[redrocker]

2000 superduty 7.3 that is pissed off
love it I was always a Chevy guy too!
Times change

[416exfreak]

spark plugs, and also do u have the right firing order on the distributor cap?

[Derag2]

where are you trying to check for spark at??????? start from the plugs and work your way back to the coil checking for spark...


Also
2003 F-250 extcab black sportpackage 7.3 PSD 4X4
Also on FTW

[user101]

Die hard Ford man right here...I'm building a 65 mustang into one hell of a rice eater...and the occasional big block chevy:devil:

[Stevie-D]

alright, got a new coil, plugs, cap and rotor, still nothing. i've got power to the positive side of the coil, as well as the negative. now, i still have no spark. does anybody know where i can find a wiring diagram for the wires for the ignition system ( ignition box, coil, distributor, etc...)

by the way, the engine is actually a 351 modified. found that out by accident today.

[quader400]

i got that same engine in my 78 bronco.. its the 351M big block right? dont know much about it though

[Derag2]

pull the distibutor and see if the drive is still on the end.....

and the 351M isn't a bigblock I've heard it called a midblock before.

[quader400]

well i know 351 isnt supposed to be a big block, they start at like 390 or something but what ive heard is thats why its called M for Modified and its supposed to be a big block. may be wrong

[user101]

Originally posted by quader400
well i know 351 isnt supposed to be a big block, they start at like 390 or something but what ive heard is thats why its called M for Modified and its supposed to be a big block. may be wrong

your right, the M stands for modified. It is a small block

[94F450SD]

the 351M is a big block.i blew 4 of them up in a week.got tired of them and dropped a 460 in thetruck,no more headaches.

but back to the original question.you need to either clean or replace the points under the rotor.you will have power at the positive and negetive posts on the coil untill the points close and ground the negative post.another thing also.on the starter solinoid on the fender by the battery you will have 2 small wires that are pushed onto 2 small posts.one is for the starter solinoid the other supplies the coil with 12 volts while cranking.check to make sure you have power to the coil while trying to start it.if you dont have power to the coil while theengine is cranking it wont start.but its most likely asetof dirty pointsfrom sitting for 10 years.go on Ebay,you can usually buy a wiring schematic for any car fairly cheap.