Ran fine this morning, now it hesitates

[68GEETEE]

'68 302 4bbl 4 speed.

Took the family to the inlaws today, approx 20 miles, engine ran great.
When we started to come home 3 hours later, the engine hesitated and missed real hard, at all speeds. It felt as if several spark plug wires werent connected, but I checked, and all were connected properly. The car has been great since I installed the distributor about a month ago, I have put over 500 miles on it since then, so I dont understand in a matter of hours why she went from running great to running like crap.

It has a Holley 600cfm , which was purchased new about a year ago.

I checked and didnt find any vacuum hose problems, nor any loose wires.

Anybody got any ideas??

 

[Doc Voodoo]

Did It Rain Out while you were inside ? Sounds Like the plug wires got wet.

 

[68GEETEE]

No rain , but was a very humid day. Still, it ran fine early, it was humid then, too. Had a half tank of gas too, I didnt fill up today, so thats not it either.

 

[mustang70]

Was it in a garage before you took it out the first time? The plug wires may have gotten wet when it was outside.

 

[68GEETEE]

garaged, but was outside only 3 hours while we visited. No rain, wires cant be wet. Timing is correct, I checked it again tonite to make sure. Fuel filter is new, anything else might cause this?

 

[Irv]

coil?

 

[2nd Mustang]

My guess would be ignition related. I had that happen too. Parked the car for a little while, then when I restarted, it had a terrible miss that got progressively worse while driving home. It turned out that the one year old plug wires were failing (after I replaced the rotor, distributor cap and plugs).

 

[68GEETEE]

My guess would be ignition related. I had that happen too. Parked the car for a little while, then when I restarted, it had a terrible miss that got progressively worse while driving home. It turned out that the one year old plug wires were failing (after I replaced the rotor, distributor cap and plugs).

The wires are about 10 mos old, Motorcraft brand. I wonder if they could be bad this quick? Car has only been driven 1500 miles in the last year, 500 of them in the last month alone. The distributor is rebuilt from Oreilly A/P, I wonder if the cheapo points they use could be the problem? I have a set of new Motorcraft points I could install, do you think new points would make a difference? Is there a way to check points on the car?

 

[pabear89]

The wires are about 10 mos old, Motorcraft brand. I wonder if they could be bad this quick? Car has only been driven 1500 miles in the last year, 500 of them in the last month alone. The distributor is rebuilt from Oreilly A/P, I wonder if the cheapo points they use could be the problem? I have a set of new Motorcraft points I could install, do you think new points would make a difference? Is there a way to check points on the car?

Pop the cap and look at the point set,
First see if they are burnt on the point face's and then check that they
match when closed. {both faces should be flat and centered on each other}
then check the gap/dewell.
PB

 

[2nd Mustang]

Points can be very difficult to work with. Even though the gap might be correct, the dwell angle could be off. It almost imperative that you have a dwell meter when playing with points.

 

[Snail50]

dump the points and get Pertronix.

 

[Pakrat]

Are the points a single or a dual set? If they are a dual set, you can always close one and see what happens, just to narrow down the culprit. Also, even though it was just rebuilt, if you do find out it is the points and decide to replace them, then replace the condensor too. They are cheap and should always be changed as a set to avoid another problem down the raod.

 

[69PaleHorse]

You said the fuel filter is new - do you know the flow rate/filtering size of the filter? It might be restricting flow. Also, I had a similar problem about a year ago and it turned out that the primaries in my Holley were continuosly dumping fuel, causing it to run really rough/rich.

 

[68GEETEE]

Are the points a single or a dual set? If they are a dual set, you can always close one and see what happens, just to narrow down the culprit. Also, even though it was just rebuilt, if you do find out it is the points and decide to replace them, then replace the condensor too. They are cheap and should always be changed as a set to avoid another problem down the raod.

single points, dwell set at 29. I will check the condition of them.

 

[68GEETEE]

You said the fuel filter is new - do you know the flow rate/filtering size of the filter? It might be restricting flow. Also, I had a similar problem about a year ago and it turned out that the primaries in my Holley were continuosly dumping fuel, causing it to run really rough/rich.

Its an inline filter off the shelf, have no idea what the flow rate is. What filter would be a good choice as far as brand / flow rate , etc??

 

[68GEETEE]

could this be something that went wrong in the carb itself? It backfired once as I started to drive home, up thru the carb. Then ran like crap the 20 mile ride home.

 

[Ronstang]

I didn't read all the above but if you haven't changed the condenser yet then do so because this sounds like a classic case of condenser crapout.

 

[RAdams`]

Yea I had a simular problem and it turned out to be the coil.

 

[Roddster67]

Blown power valve?
Moisture in the distributor cap?
Bad gas?
Full moon?

 

[Pakrat]

Quite often a backfire is a direct result of improper point gapping, and the points and condensor are a pretty cheap fix. I would replace them both, bump the motor until they are wide open and make sure the gap is perfect, double check the timing and see if the problem persists before you tear into the carb.