i've got a 79 f250 with a 351 . . . a couple of nights ago it died and wouldn't start back. the carb is getting gas, i changed the distributor cap and rotor, i changed the plugs and wires, and i changed the ignition coil but it's still not starting. it cranks but won't start. any idea about what to try next?

 

Jumped time?Bring #1 cyl up to tdc and pop the dist cap and see how close the rotor is to #1 cyl.If it's far off, the timing chain jumped a couple teeth.

ps: it could be the ign module, the little square box on the fender well.If it is not firing.

 

If it's a Duraspark ignition I'd try the box. Some places can test it for you. Also check in the dizzy for broken wires etc.

 

Could be the pickup coil in the dist.

 

Does it have spark? Use a spark tester on a plug wire and test for spark. Or you could use a spark plug that is grounded well, or hold the end of the wire and see if your hair stands up...

No reason to replace a good part, if you can avoid it.

Marty

 

thanks for the ideas. it is getting spark, so i'm checking the timing tomorrow. a friend seems to think i need a new chain.

 

get the chain set for a 1971 LTD/Marquis with a 400. you wont be sorry.


good for 20-30 hp, and about 1 mpg better mileage.

EDIT:
I'm assuming its a 351m, if its a 351w, then get the 71 chain for that.

All User's Please feel free to use the EDIT button rather than the Post reply button

 

Your best buy if you need the chain is to purchase aftermarket, complete with double roller chain, and steel gears. Ford used nylon gears(not one of their better ideas) as well as a slider type chain, which tends to stretch more over time, and isn't as smooth as the double roller chain. If you're feeling energetic and want to convert to an electronic fuel pump and mechanical pump block off plate, you can convert to a dry timing belt system, which will be even better in the long run. Slider chains provide the most vibrations, which in turn cause ignition "bounce", double roller chains are much smoother, so your timing becomes more accurate, belts are the easiest conversion and provide the best bang for the buck on timing accuracy. If you want to go all the way, and are willing to put the time in, a reverse rotation cam, bronze distributor gear, and marine gear drive timing are the most accurate, but expensive. Mileage goes up with each step, you decide. I'd go for the double roller chain and metal gears myself, with the belt conversion being the next in line. Unless you're willing or wanting to do a good blue-printing job on the engine, the marine gear drive timing is to much money and to much work to bother with. The double roller chain and gears are bolt on, no conversions necessary, and a nice touch. Get a new fuel pump drive cam while you're in there, and a new fuel pump as well, to make everything as smooth as possible. Won't hurt to replace the harmonic damper as well, as they very commonly dry out, and the timing marks spin off their mark, causing extra vibrations as well. The less vibration, the more accurate your timing and ignition are, the more accurate they are, the better your engine performs, and the better mileage you get.