Hi everyone. To start off my trucks a 78 f150 2wd a/t with the 351m its stock no mods but an air cleaner. My issue being no spark currently but let me recount this wonderful tale leading up to where we are now. So the truck runs and drove great before all this. We were headed across the country headed to colorado and the bearings in my alt seized up i drove the remainder with out an alt and got one when i got to my destination which was a nice 75 amp out of a newer 80s pickup charged the system fine etc. Drove around fine on the way to michigan my battery boiled over on me while driving i proceeded to an autozone to swap out for a new one cleaned up the terminals and anything else acid came in contact with trucl started right up i put her in reverse it stalled out and hasnt fired and ran consistently since. As it stands ive replaced the voltage reg. Ignition control. Plugs. Wires. Cap and rotor. The coil and even the pickup in the dizzy throughout changing them i had a weak orange spark to start so i decided to check all my grounds fuseable links etc. The wire going from the coil to the ballast resistor was frayed so i stripped it and reconnected it because i couldnt find anyplce that sold one. It gave me a decent white spark on 1. I checked my timing just to see and i set it at 8 btdc i got it to fire and run but it ran like *** i had to feather it to keep it running but stalled out shortly after firing i then lost spark on 1 so i checked every individual cylinder for spark and found i had good spark here weak spark there and no spark on others so i replaced the cap and rotor and wires now i have nothing. Checked to verify spark at coil and nothing there that i can tell i tried checking by the negitve post and it seems as if it might be interupting but its a dull glow and seems constant if not a slight blink while cranking. Im all out of ideas and cant seem to find another lead browsing the vast database of knowledge here and across the web so im hoping someones had a similar if not the same issue and can atleast give me something to go on any help is appreciated for sure. Thanks in advance

 

I am going to dive in and tell you something that isn't too preached here but it has cured 2 of my fords of all duraspark, voltage regulator and charging problems

1st best thing ever made is a HEI distributor.. It has 1 wire (ONE) 12v + signal to spark..

Second was my over/undercharging, battery boiling, dash light popping problems that I did away with with a GM 2 wire alternator.. 1 charge wire, 1 12v+ wire activation..

I do these swaps now as soon as i pick up these trucks.. The factory systems on these trucks are excellent and durable but all it took was me loosing sleep one good time

 

Whats the usual cost of doing the hei and gm alt? This trucks been my daily driver for years now and this is the only trouble shes given me and its driving me batty haha.

 

Consider the Ford 3G alternator upgrade instead of GM as most times it's a bolt on affair. It's easy enough to use the search function to read up on it.

Then deal with the wiring, which is usually simple unless you have an Ammeter. Then it kinda gets a bit messy. But not impossible!

 

You can pick up a brand new hei for about 60$ off eBay and a brand new alternator for about 25$ from a partshouse..

Maybe someone can chime in and help you troubleshoot what you have, I don't want to shoot a fix in the foot.. Iv been where you are, it can be a pain, keep your head upl

 

There's a company that makes an external regulator for the 3G alternator upgrade so you can keep your ammeter - it's linked in one of the sticky threads.

As for the current problem, I'd take a step back and look at some basics: was something hooked up backwards somewhere in that process? Are the grounds good (i.e. negative battery cable to block, etc.)? What voltages are you measuring at the coil, ignition module, etc. with the key on?

 

Well i swapped out the coil and bam i have spark now but its still not running. I can go out in the morning and pump the crap out of the gas and itll start but it runs like *** for about 20 -30 secs. And die out i loosened the distributor to mess with it before it backfired a couple times real bad now im wondering if i blew the powervalve in the carb i still dont know if im in time. Whats the easiest way to time it without it running? Ive looked all over fpr a starting degree most say 8 or 6 or 14 its a california built truck had emmisions etc. Any suggestions?

 

I usually turned the distributor until the engine ran by itself. Trial and Error. Then toss on the timing light to make the final setup. Or use the ol' timers vacuum tune. Or time by ear until it pings and back off a bit.

 

Timing light can still be used while cranking. Double check firing order making sure wires are fully seated since you have moved the plug wires at least twice. Only blown power valve I've had is on a Holley 4V carb.
You need a multi-meter. Voltage at coil should be 12v when cranking, 5.5-6.5v when running. Google "duraspark testing procedure". The full test procedure in .pdf form is available at www.bobcat.ca/stuff/DOCS/DURATR~1. Sadly, you can not trust new parts to be good anymore.

 

You got the right firing order? Back then ford used like 3 different firing orders, Is yours stamped on the manifold? and make sure you got the wires in the proper rotation, clockwise or anti-clockwise, pull the cap and tap it over to make sure which way the distributor turns. Some models used 1-5-4-2-6-3-7-8 and others used 1-3-7-2-6-5-4-8 and the distributor should spin counter clockwise. But you never know. I would double check

 

Thanks for the input guys. I tried just turning the dist. Till it ran i can get it to fire and run for about 20-30 seconds but i have to feather it and it promplty dies out and i cant get it to fire again till the next day. Ill check the firing order again its stamped on the manifold i believe totally possible i crossed a wire. Ill update when i can thanks again.

 

Yeah its a sad fact when even new is junk.

 

Well guys i checked the order and such and it was right did some more looking and i discovered a sea of gas in the intake cant get much air down her throat eh? It backfired twice really hard so it doesnt suprise me something went caput. im going to rebuild the carb and get the intake cleared and see what happens hopefully a little air fuel mixture and some spark will make her go boomx8 again. Thanks fer all the advice ill update.

 

It sounds like a carburetor problem.. If the venturies aren't surgical clean they will constantly drip gas

Could be caused by a needle seat, the float set too high or a clogged jet..

I don't think timing is the issue, sounds like a super rich situation

 

Def. A carb issue at this point. Like i had said i had hell with the ignition system and trying to sort it all out i loosened the distributor and twisted it out of time to eliminate timing as the issue and in doing so after fixing the ignition issue with the timing way off it backfired twice like ear blistering loud and after that and setting the timing and it not firing still i checked everything over again and noticed the sea of fuel in the intake after i removed my carb and pumped the throttle it just pissed fuel out so im guessing its my current issue. 20$ for a rebuild kit whats another 20$ lol atleast my durasparks brand spanking new and ill have a fresh carb.