I have a 1979 F-250 Ranger 4x4 with the 400 c.i. and manual tranny and edelbrock 1406 carb with electric choke. I have been fighting this thing when it is cold, it just doesnt want to start when cold. It runs fine when warmed up (if you can get it started). I have always assumed the choke was screwed up. I just realized this morning that if you rotate the dizzy almost all the way clockwise it will start!! What does that mean? It doesnt like to be rotated that far, you can kinda hear it trying to lock up...but it will start that way. Is there a possibility I just need to put in a new timing kit? Any help would be appretiated, thanks.

 

Really what you need to do is get a timing light on it. IIRC, m/t's should be set at 10-12*. If it's within spec, I doubt timing is your problem. But if timing is too advanced, you'll have hard start issues.

 

Well, the timing was within specs and wouldn't start. But then I rotated the dizzy big time clockwise and it started up. I can guarantee with the dizzy rotated that far the timing is way off. The trouble is it doesnt run right with it rotated that far. So I guess the way it is when its cold I can rotate the dizzy to get it started and then rotate it back after it is running (what a pain). That is why I am trying to figure out what would cause this behavior so that I can fix it.

 

What's it doing when it won't start, crank with no fire, fire but not speed up?, slows down when it fires?

By turning it clockwise your advancing the timing, so I'm guessing it cranks, fires, but doesn't really speed up and get going. This leads me to ask, are you checking the timing with the vacuum advance unplugged? If not unplug it, see if the timing goes down and recheck the timing.

Of course your timing marks could also be off, if it's in your skill level check your TDC.

 

I don't think there is anything wrong with the timing. When it is stone cold, you have to WAY advance the timing to get it to start. Once started, you can rotate the dizzy back to set the timing at 12 degrees or so and it runs fine. It has been suggested that I could have minimal compression or a major vacuum leak. Are either of these a possibility? Or is a better bet the carb is fried? I found a brand new carb on craigslist that I am considering but I dont want to buy it if it isnt going to fix my problem. The problem with the low compression thing is that once started I think it runs too good to have poor compression or a major vacuum leak. Any ideas? I am going to get a compression gauge today so hopefully I can rule this out.

 

One last time, if it will start by advancing the timing like that then THE TIMING IS OFF!!!!!

Is the choke closed on the carb, if so it's fine.

 

Meaning...what? Do I need to get a timing set for it (new sprockets and chain)? Or? Once it fires up we can run the timing within specs just fine.

 

Did you originally set the timing with the vacuum advance disconnected?

 

I'm trying to help and in doing so asked certain questions, I asked these for a reason I can't see or hear your truck from here. Let's try it one more time.

If it truely is at 12deg before you "WAY" advance it(how much is that anyway) then your at idk maybe what 30,40, more, this is IMPOSSIBLE for the engine to start with the timing that far advanced at initial, my only logical conclusion then is that 12 isn't actually your initial timing. That something is happening to throw your measurment off.

Sense you have mentioned the timing is set at 12 I assume you have a light and know how to check it. Are you checking it with the vacuum advance unplugged?

What's it doing when it won't start, crank with no fire, fire but not speed up?, slows down when it fires?

Does it run strong once started?

I suggest just turning the distributor to where it has to be to get it to start and go from there, post what that timing reading is? is it idling fast? is the vacuum plugged in? will it rev/drive? if not what does it do? without turning the timng back will it start when warm?

Just forget about setting it back to 12 for a while and let's see what it does, chances are your 12 measurement is wrong likely becasue the balancer ring has slipped.

 

I set the timing with a light with the vacuum advanced disconnected and plugged. When stone cold, it will start if you spin the dizzy damn near as far it can possibly go clockwise. Once started, you can spin it back and it runs strong. If you leave the engine with the dizzy rotated that much it does NOT run good. After warmed up if the dizzy is rotated that much you can hear it trying to lock up when cranking, which is exactly why I rotate it back after it had started. It is getting spark and fuel while it wont start. It cranks normally. I dont know what you mean by "speeds up". The cranking is steady, if thats what you mean. The ONLY issue that I seem to have is with starting stone cold, other than that she runs great.

 

Engines that won't start will typicaly do one of 3 things;

1. Just crank and crank and crank, no sounds of the cylinders sparking or trying.(weak or no spark)

2. Crank and fire, but you get this little attempt to start with the cylinders firing but it won't fire hard enough to actually start and run.(not enough advance)

3. Crank then stop or slow dramticaly when a cylinder fires forcing the starter to push harder.(too much advance)

I'm gathering then that when cold before you turn the dizzy it does 1 or 2, and when worm and the timing advanced it does 3?

Hows the condition of your ignition system, stock? plugs and wires in good condition? etc.

The choke is closed when trying to start, right?

 

Yes, when cold and the timing is where it is supposed to be it just cranks and cranks with no evidence of it even trying to fire up. Ignition system is all stock. Plugs, cap and rotor are all new. Choke is closed and opens up when warmed up.

 

2 ways to go here then, ignition is too weak during cranking or timing is off. The fact that it will start when you advance it is a symptom that the timing is off. But no fire at all during cranking says the ignition is weak, at least during cranking.

Probably a little of both, check voltage at the coil during cranking.

Get it warmed up and find the most timing it will still start with.

 

So...if the timing is off, would a new timing set fix that? What is the voltage supposed to be at the coil while cranking?

 

If by "timing set" you mean the sprockets and chain that drive the cam, then NO not sure why you keep going back to that. Were talking ignition timing not cam timing, if the cam was off it would run like crap all the time.

Voltage will depend on your battery, voltage at the + side of the coil during cranking should be close to battery voltage during cranking.