Crank, no start...check my work

[Chowbird]

Hi guys. 352FE carbureted with points ignition. When cold, starts right up on first turn of key. No pumping throttle, just starts right up. Run it for a short time and it will not start if shut off. Cranks, shoots a miss or hesitation every couple cranks, no start. Will even die while running sometimes. Shuts itself off, coast to a stop, crank, no start

Checked battery. 12.6
Checked alt. 14.8. 13.8 with everything on
Held throttle wide open and cranked. No help
Shot starter fluid down throat. No help
Put a little gas down throat. No help
Checked for spark at distributor from coil. Yes
Checked for spark at the plug... NO. (May be operator error checking for this spark, but I'm reasonably sure there is none)

Does this mean bad distributor? Or rotor. How can I check the rotor, just take off the cap and have someone crank it?

Would heat cause these problems in the distributor?

Thanks a bunch

Tim

 

[suckerpunched]

Assuming your spark checking method is sound. If the coil wire that connects to the center of the dist cap has spark when cranking but the plug wires do not. the problem is the cap and rotor, look for corroded terminals where the plug wires plug into it and on the inside of the cap itself, corroded, broken or cracked rotor. cracks or carbon tracks inside the cap.
for 4 bucks you can buy a spark checker like this. works good for what you are doing.
http://www.amazon.com/Fool-proof-En...8004304&sr=8-1&keywords=ignition+spark+tester

 

[patterdale]

Sounds like it could be one of a few things. If point ign. Could be bad points. Could also be the rotor. Could be a cracked/carbon tracked cap. Runs fine when started cold and has problems when hot or won't restart when hot means heat is bringing out some component failure. A bad coil can fail when hot. I had a generator once that ohmed out perfect sitting still but would not put out any current when running. It was called a " flying open". When I ran the engine and got it spinning something somewhere would separate and not let current flow. I know, not quite the same problem but equally frustrating.

 

[Chowbird]

So yes, I went back out to confirm my no spark test validity at the plug. It had no spark when hot. Let it cool for an hour, started right up

So my question is how can I diagnose the components of the distributor. Can I just pull the cap, crank the engine (helper) and see if the rotor turns? Then just align the cap with the tabs and put it back on? Any way to check the points or condenser with a multimeter?

Are any of the components inside the distributor heat sensitive, ie fail when hot, work when cold?

Thanks. I really appreciate it. I'm learning quickly

 

[bdavis70]

I'm fighting the same issue myself right now. My motor will drag real hard when I try to restart after it is warm. I have had condensers go bad and it would not start. My method is to keep replacing things till I solve the problem. I hope you have better luck than I am having.

 

[suckerpunched]

in very basic terms, the points are down below the rotor, they tell the coil when to create a spark. the spark travels back to the dist cap via the coil wire and the current goes through the center contact in the cap through the rotor and to one of eight spark plug contacts depending on which way the rotor is pointing at that time. if the coil is shooting sparks out through the coil wire, the stuff in the lower dist and coil are functioning. yes you can remove the cap and look at the rotor. the rotor pulls straight off, only goes back on one way. you can watch it turn if you want to, but if it not turning it would never run, and you have a more serious problem. the rotor has, or should have a springy tab on the top of it that makes contact with center of the cap. the pointy end makes contact (well almost, the spark has to jump a small gap) with the individual spk plug contacts around the cap. Now if the coil wire is not sparking when the condition occurs the coil, points, wiring could be bad. all those things can definitely be affected by heat.

 

[rmk57]

When you do get it running and shut it off, take the air cleaner off and check and see if there is fuel running out of the boosters and flooding the engine.

Stuck float, needle and seat........


Randy

 

[suckerpunched]

there are ways to test how strong the spark is coming out of the coil, I suppose its possible that a very weak coil could spark but not have enough power to send the spark through old crappy high resistance wires, usually they spark or they don't, but it is pretty common for a coil to quit when it gets hot so double check that there is actually a good spark coming out of the coil wire.

moisture inside the cap can and will cause issues too. if you think it could be damp, dry it out. obviously sparks arcing out of bad wires to ground will cause misfires or failure to run if its the coil wire thats arcing.

 

[suckerpunched]

by the way, whats the 352 in?

 

[Chowbird]

352FE is in a '76 CJ5. Overkill a bit, but it was POs shop fun truck...they restore Jaquars...go figure

My '69 Bronco runs like a friggin top. No issues, no hassels...the alter ego of the CJ

 

[suckerpunched]

yeah thats an unorthodox combination. those FE's are cool engines. We have about 50 of them where I work. running wind machines to keep citrus warm in winter. bet it's a tight fit in a Cj.

 

[Justafordguy]

I've seen condensers quit when they get hot and work again when they cool off. I would try that first. Check the points while you are in there.

 

[suckerpunched]

If you want to know the more complicated version of how the ignition system works, you can read this.

http://www.linnbenton.edu/auto/perform/ignition.html

 

[WSM29]

Had a number of bad coils do exactly what you are seeing. Had an old ford that I was driving home that I had to pull over after about 10 minutes of driving and let her sit for 20 minutes... PITA but I saved the tow bill! New coil and she ran great again.

 

[Chowbird]

So it comes down to good spark from coil into distrib. No spark at the plugs. I was thinking it was the condenser also, but wouldn't the fact that there is spark from the coil take anything that's in the primary circuit of the offender list. Wouldn't it have to be a secondary ignition prob. I was really hoping it was something simple like the condenser. I will be able to start working on it tomorrow. Thx for any advice.

 

[suckerpunched]

So it comes down to good spark from coil into distrib. No spark at the plugs. I was thinking it was the condenser also, but wouldn't the fact that there is spark from the coil take anything that's in the primary circuit of the offender list. Wouldn't it have to be a secondary ignition prob. I was really hoping it was something simple like the condenser. I will be able to start working on it tomorrow. Thx for any advice.

in my opinion, most likely yes.

Cap rotor and wires are pretty simple too. if they are old and haven't been changed in awhile, it probably needs them anyways.