69 383 RR bucking

[mpro69rr]

Hey all!

I took the roadrunner out for a long drive and this happened a couple of times. I was going about 50 mph and it started bucking, it did it twice then was OK. I got to where I was going and came back and at about 30 mph it bucked 3 times. This has never happened before and was wondering what causes something like this? Do I need new spark plugs or something else? Also I have a pertronixs electronic distributer. As always thank you for the help!

 

[furious70]

Fuel filter is first place I'd look

 

[Don Frelier]

1. Filter perhaps... easy to change and cut the old one in half to inspect.
2. Do you have a newer fuel pump pushrod?
Their have been numerous cases of new ones wearing quickly. (really quickly)
3. Or your losing power to the ignition.
Pull the bulkhead connector apart and inspect the run wire to the ballast resistor.

 

[mpro69rr]

Fuel filter is first place I'd look

AH, I never thought about that, I'll check it out, thanks!

 

[mpro69rr]

1. Filter perhaps... easy to change and cut the old one in half to inspect.
2. Do you have a newer fuel pump pushrod?
Their have been numerous cases of new ones wearing quickly. (really quickly)
3. Or your losing power to the ignition.
Pull the bulkhead connector apart and inspect the run wire to the ballast resistor.

I've had the new pushrod for about 800 miles. I don't think it is the bulkhead connection because everything is new wiring on both sides, but you never know, I'll poke around. I'm going to check the fuel filter, its a metal one with a micro filter in it, not a paper one.

 

[Don Frelier]

Oh boy.
Now I'm afraid it might be the pushrod.
Hope not.

 

[mpro69rr]

Oh boy.
Now I'm afraid it might be the pushrod.
Hope not.

Oh boy, is right, I hope its not that either! I know I bought the best one out there so we will see.

 

[Bird 426]

Did you get a new chinisium fuel pump too? I had one fail almost immediately on a daily driver. Ran, wouldn't, stumble.

 

[mpro69rr]

Did you get a new chinisium fuel pump too? I had one fail almost immediately on a daily driver. Ran, wouldn't, stumble.

It probably is, I had one fail early on too. Everything everyone is saying, I guess means that the bucking has something to do with fuel one way or another.

 

[joel snyder]

gas tank in my duster caused this. rust.

 

[Geoff 2]

If this happens suddenly & without warning...& corrects itself just as suddenly, I would suspect an ign problem.

Remove & check the plugs; gaps too big, cracked porcelain. If they are old, replace them.
Check hi -tension leads for resistance; check rotor & cap for carbon tracking. Check carbon button in the cap.
Could be the Pertronix module.

 

[mpro69rr]

gas tank in my duster caused this. rust.

Fairley new gas tank.

 

[mpro69rr]

If this happens suddenly & without warning...& corrects itself just as suddenly, I would suspect an ign problem.

Remove & check the plugs; gaps too big, cracked porcelain. If they are old, replace them.
Check hi -tension leads for resistance; check rotor & cap for carbon tracking. Check carbon button in the cap.
Could be the Pertronix module.

Yes, that's how it happens. I will check these things, Spark plugs are about three years old. Thanks!

 

[AR67GTX]

If it’s just a few random cut outs at light cruise, I would second the ignition source. At light cruise the fuel delivery requirements are pretty low and the fuel bowl capacity should be enough to prevent a complete, momentary loss of combustion. A continuous, lean stumble or backfire through the carb would be more indicative of a fuel issue. If it’s like the engine just stops running for a brief moment then I would be more inclined to look at the coil, a bad plug wire, perhaps an electronic ignition module or amplifier. Just an opinion.

 

[mpro69rr]

If it’s just a few random cut outs at light cruise, I would second the ignition source. At light cruise the fuel delivery requirements are pretty low and the fuel bowl capacity should be enough to prevent a complete, momentary loss of combustion. A continuous, lean stumble or backfire through the carb would be more indicative of a fuel issue. If it’s like the engine just stops running for a brief moment then I would be more inclined to look at the coil, a bad plug wire, perhaps an electronic ignition module or amplifier. Just an opinion.

It does seem like it stops running for a moment then runs again. I am hoping its just the fuel filter, I ordered a new one. Its sounding more like it could be something with the ignition. I'll have to take it one step at a time and check everything. Thanks!

 

[mpro69rr]

I found the problem so I thought I would update. I haven't worked on the car for a while and did not look into this problem. I started to work on it again trying to upgrade my cooling. Well, while replacing the radiator I look down and saw my negative battery cable touching my power steering pully, I lifted it and sure enough there was wire showing. Replaced the cable and the problem disappeared! I didn't even think of checking things like that, glad I was working on my cooling and found it. Thanks for all the suggestions.

 

[Geoff 2]

Happy days & no $$$$ spent!!