What is causing my misfiring while driving ?

[Evan Frucht]

Well I took the distibutor out again. Looked at it carefully. Double checked everything. Then broke out the timing light again and set the timing with a little less advance than before. I set it pretty high the other day for some reason.... at like 25 initial. Now it's at about 15 or so. The timing mark was jumping around back and forth randomly with about 1/16" variation while idling. When I reved it up it looked like the timing mark went to about 35. At a certain rpm the timing mark started to jump around a lot and all over.

THEN, it was sounding pretty decent so I drove it around the block for 5 minutes and the misfiring seems to have stopped

I really wish I could make this thread productive and say what caused this but I can't... part of me isnt fully confident its solved. Time will tell.

 

[khryslerkid]

 

[Evan Frucht]

Ok well. Car is still acting funny. Drove it around today for 30 minutes or so. It was acting normal, felt good... but then after about 20 minutes its seemed to happen again and started acting up. As I making a sharp turn into a gas station the car died on me. Then I got I started again but It was acting up the whole way home making me nervous...

The engine seems to not like it when I turn the wheel completely around to the make the sharpest turns. Could that be something ? Or is it my imagination?

Maybe once the car fully warmed up (after about 20 minutes driving around town) it threw my new tune off?

Any ideas would be lovely

Thanks!

 

[khryslerkid]

Have you ever checked the float level in your carburetor?

 

[Evan Frucht]

Have you ever checked the float level in your carburetor?

I did and fine tuned the adjustment when I first rebuilt it a year ago. It's been running good since then. I suppose I could have messed it up when I laid the top of the carb on the bench? I sat it down very gently though

 

[khryslerkid]

I did and fine tuned the adjustment when I first rebuilt it a year ago. It's been running good since then. I suppose I could have messed it up when I laid the top of the carb on the bench? I sat it down very gently though

That would have raised the float level sitting it down with enough force to bend the tab/float.

I was thinking of a low bowl level. When going around a turn it might effect fuel supply.

(Still thinking )

 

[Ski 61701]

Evan, when you suck on the vacuum line to vac advance on distributor you should see the advance plate rotate a bit... This plate should move with little resistance. if you hear a hissing noise and no movement of plate the advance cannister is toast. I would confirm if it holds vacuum if it does, lubricate all pivot points on advance plate. its not uncommon to have things seize up. if its binding, and then releasing, I can see that giving you some of the symptoms you describe. This last go around where you monkeyed with it and it drove ok to me is you somewhat freed things up a tad hence it driving a little better.
Some vacuum cans have an allen set screw inside, you pull off vac hose and stick wrench in and either tighten or loosen to change amount of vac needed to move the plate. if you have a fair amount of rust dust under the cap, clean it off and retest.

 

[Evan Frucht]

Evan, when you suck on the vacuum line to vac advance on distributor you should see the advance plate rotate a bit... This plate should move with little resistance. if you hear a hissing noise and no movement of plate the advance cannister is toast. I would confirm if it holds vacuum if it does, lubricate all pivot points on advance plate. its not uncommon to have things seize up. if its binding, and then releasing, I can see that giving you some of the symptoms you describe. This last go around where you monkeyed with it and it drove ok to me is you somewhat freed things up a tad hence it driving a little better.
Some vacuum cans have an allen set screw inside, you pull off vac hose and stick wrench in and either tighten or loosen to change amount of vac needed to move the plate. if you have a fair amount of rust dust under the cap, clean it off and retest.

I'm almost postive my vaccum can is bad. Blowing through it and sucking through it both made a hissing noise. It is not holding the suction at all. I can tell if I blow into the hose, air blows out a little hole on the top of the canister.

 

[Wietse]

What about your ignition coil?
Did you ever try another one? (I did not read anything you changed it..so)

 

[Don Frelier]

I'm almost postive my vaccum can is bad. Blowing through it and sucking through it both made a hissing noise. It is not holding the suction at all. I can tell if I blow into the hose, air blows out a little hole on the top of the canister.

Then you need to replace the vacuum advance or the distributor.

 

[Ski 61701]

I'm almost postive my vaccum can is bad. Blowing through it and sucking through it both made a hissing noise. It is not holding the suction at all. I can tell if I blow into the hose, air blows out a little hole on the top of the canister.

Yup, time for new one, those are made for suction.. I bet you get another distributor to test out and make sure vac advance holds , and advance plate moves freely you'll be back to having a dependable driver with better gas mileage to boot

 

[Evan Frucht]

Ok so car broke down again.

Just a quick rundown... since posting this thread I replaced the following

- New Distributor
- Cleaned carb and reset float height and then re-tuned
- initial advance set at 16
- new starter ( becuase old was was starting to sound like it was going out )

After doing that my misfiring and stuff stopped for about 150 or so miles of driving.

Then last night I broke down again... Was running errands all day yesterday. The car started to run bad and wanted to die at idle. Then I stopped at a friends house for a few hours and the when I went to leave the problem seemed worse and I made it about 1000 feet down the road...

Had to tow home at that point as I didnt trust it...

The car is very hard to start. I smell fuel. While trying to start it, it was backfing through the carb I think ( saw maybe some smoke seeping out of air filters ) when I popped the hood at that moment....


Not sure what to check first or what might be causing this

 

[bandit67]

Pull the valve covers and do a valve train inspection or do a compression check to make sure you do not have a damaged valve. Sounds like something is still not correct with the carb. Sounds like the float level may have changed. Can you borrow a known good working carb to ensure thats not the trouble......

 

[khryslerkid]

Check fuel for water contamination.

Try another condenser.

 

[Evan Frucht]

Pull the valve covers and do a valve train inspection or do a compression check to make sure you do not have a damaged valve. Sounds like something is still not correct with the carb. Sounds like the float level may have changed. Can you borrow a known good working carb to ensure thats not the trouble......

I've gone through the carb many times already and I dont think it's the carb so I'll start with a few other things.... and last time I carefully set the float height and drop to be correct. What would cause it to go out of adjustment so quick?

I'll try a new condenser today I have one.... but this distributor is brand new... just bought 2 weeks ago. It's possible it already failed somehow tho.

I'll pull the VCs and see what I can find. And do a compression check I've been meaning to do that.

 

[Evan Frucht]

Check fuel for water contamination.

Try another condenser.

Fuel is most likely fine. I had just filled her up, and also never let the gas get old or sit long.

I have a new condenser to try

Thanks for the ideas

 

[Evan Frucht]

I'm thinking the ballast resistor might be suspect. It's very hard to start and wont stay running. Going to get a "spare" one of those to try while I'm at it.

 

[Evan Frucht]

Also, the fuel I was smelling likely came from the gas can I forgot I had in the car.

 

[Don Frelier]

The ballast resistor is generally either good or bad.
You can unlug either side and test with a ohm-meter but it wouldn't run at all if the resistor was bad.
Bad = No continuity.

 

[Evan Frucht]

The ballast resistor is generally either good or bad.
You can unlug either side and test with a ohm-meter but it wouldn't run at all if the resistor was bad.
Bad = No continuity.

I was under the impression it was possible for it to lose its ability to restrict the current. I was thinking maybe its not functioning right and too much voltage is going through points. Maybe it fried the new condenser?

One classic failed ballast resistor symptom is that the vehicle will start but then immediately die. It is actually doing that... but sometimes it will stay running for a little if I keep giving it gas... other times... no. The few times where I was able get it started and running briefly, it would immediately die once I put it into gear.