I have a 69 roadrunner 383 4 speed. bought the 383 from a guy that said it was built but have no idea what was done to it. I have the motor in and runs good sitting in the the shop revs up good. put it in gear and it hesitates on giving it gas and then takes off also running at 2500rpm to 300 rpm it surges. Had a 650 holley on it so I changed to a 750 quick fuel I took off my Cuda 440 and it does the same thing on roadrunner but runs good on Cuda. The car has 430 gear. it still has points in it and all are new coil points cap plugs Wires ectopic. Is this a fuel problem or ignition ?
Need help
- Thread starter Hounddog
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dieseldazzle
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What's the general state of the fuel system? Igniting system?
Compression test good?
I had same problem recently and ended up being gas that was only 7 months old
Compression test good?
I had same problem recently and ended up being gas that was only 7 months old
miller
Well-Known Member
Could be a combination of both fuel, and ignition. Besides making sure your timing is right, might want to check the advance rate, and amount, to be sure it falls in line. Could be sticking advance.
miller
Well-Known Member
Sounds good!
But, for what it's worth...new doesn't mean much, without a couple checks. Both your carb, and distributor were put together with human hands.
How is your fuel pressure?
On the dizzy, single, or dual point? Mechanical, or vacuum advance? At the very least, pull the cap, and 'feel' the advance at the rotor. Should move freely, both ways, the advance springs pulling it back into place. Is the advance shaft lubed? You pull the rotor, and should be a 'wick' at the top of the shaft, that takes a couple drops of oil. Each time you tune.
Just simple stuff, but needs to work right, to act right. Using a timing light, can you see the advance work?
But, for what it's worth...new doesn't mean much, without a couple checks. Both your carb, and distributor were put together with human hands.
How is your fuel pressure?
On the dizzy, single, or dual point? Mechanical, or vacuum advance? At the very least, pull the cap, and 'feel' the advance at the rotor. Should move freely, both ways, the advance springs pulling it back into place. Is the advance shaft lubed? You pull the rotor, and should be a 'wick' at the top of the shaft, that takes a couple drops of oil. Each time you tune.
Just simple stuff, but needs to work right, to act right. Using a timing light, can you see the advance work?
dieseldazzle
Well-Known Member
Balancer slipped??? Maybe timed wrong what happens when you play with the timing?
Ranger16
Well-Known Member
I know you said you could not find a vacuum leak, but the symptoms you describe sure sound like one to me.
I have adjusted the timing out to 18deg still the same just harder to start. I have sprayed all around carb and intake for vacuum leak nothing even put a rag over carb when running and car goes dead so I assume I don't have a vacuum leak am I missing something to check
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Unlikely, but does it have power brakes? A friend is currently changing out his diaphragm that was causing his vacuum leak.
413 belvedere
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My 413 did the same thing, ended up being too lean on primary jets, may not be your issue but sounds like it could be, light throttle motor surged give it more gas and would go away until light throttle, just a thought
PurpleBeeper
Well-Known Member
Hmmm... fuel filter clogged? Check distributor advance like others are saying. Did it ever run right? I mean, could the cam be way off from a not-so-good centerline adjustment job? Maybe jumped a tooth on the timing gear?
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