Running on 4 cylinders

Ok, a little background, It's a 73 with a 302. It has a Performer RPM Intake and a 600 CFM Edelbrock carb. I have replaced the plugs, wires, coil, and have upgraded from Points to Pertronix.

Now for the problem. All of a sudden today the car started to run horribly. It won't idle and smells horribly of unburned gas. Any time I let off the gas pedal the engine dies. I think the car is only running on 4 cylinders. I am completely stumped on this one. Any help would be greatly appreciated.

Thanks,
Jonathan

 

Sounds exactly like what my car did when the valves seized.

 

How hard would it be to replace the valves? I'm a decent mechanic, but don't have a garage to work in.

Jonathan

 

First thing I would do is pull the spark plug wires one at a time and figgure out which cylinders aren't fireing. Pull the plug and check to make sure you are getting good fire on that cylinder. If so, pull the valve cover and have someone turn the motor over while watching to see if all the valves are opening and closeing.

Hardest part about takeing a valve out is takeing the head off. Then you just need a valve spring compressor. I rebuilt my head on my back porch..

 

I'd bet its electrical. If you have an induction timing light, put it on each plug wire to make sure they all are firing. Pertronix can be defective even when new. If all the wires are firing, then look else where. Valves are easy to check by pulling the valve covers and watching the rocker arm action while the engine is cranking. Remove all the plugs first so the starter doesn't work so hard. If they are all working, then run a compression check. That will tell you if you have any burnt valves.

 

check the dizzy cap and rotor also, they may be going bad. and since you just changed the plug wires, double check they arent crossed up in your firing order and that they are seated correctly and conducting well. these can also be bad from the store. Good luck

 

same symptom of mine yesterday

I upgraded point to pertronix yesterday....I forgot to put back my ground wire in the distributor and I check my coil if I have 1.5 ohm or more...and I open 1/4 more each side the gas screw of my holley carb....now she run good http://www.mustangmonthly.com/howto/173_0310_pertronix_ignitor_ignition/

 

Mine did the same thing...4 of the valve lifters got gummed up after sitting for years, and bent a couple valves. 8 cyls running on 6, and stunk like gas. Had a nice lope, though...

 

Well, today I replaced the plug wires and and plugs and the idle is back to normal, but there is still the smell of gas at idle. Any ideas?

Jonathan

 

Hell, my 6 cylinder was running on 3 cylinders! And the car drove like that! Barely made it up a hill though.

 

Is the gas smell under the hood or coming out the tail pipe?

 

Glad you fixed the bulk of it without having to disassembling the motor. Gotta try the cheap easy fixes first, usually take care of the problem.

 

The gas smell is under the hood.

 

i would check all your lines for cracking and the clamps are tight and the fuel pump isnt leaking. then adjust the idle to a little bit lean. if it doesnt go away, make sure your carbon canister isnt filled with overflow. make sure there arent any wet spots around the carb also, especially near the accelerator pump and bowl overflow. there will always be a little fuel smell from the carb, but you dont want a hood filled with vapors.

 

ok, It's getting dark, so I'll check those first thing in the morning.
Jonathan