btw

Hoping for a simplicity answer on this question guys. And it may be in the fuel.

Like many of us on the east coast (I'm in NC), we suffered through a gas shortage in the last few weeks due to the pipeline problems. I always run ethanol-free gas in my 394BB. That gas wasn't readily available and I needed some to make a regional show.

In the absence of it, I used 97 octane and then put in a lead additive about two weeks ago. The car has run fine until this morning. Turning the key will get the engine to turn over but then it quits likes it is starved of gas. This morning it backfired and threw a flame burnoff out the rear exhaust.My battery is down to 70% so I am charging that.

I have a new starter, new spark plugs and wires. I'm wondering if the ethanol gas/lead combination has gummed up carb? Or if it is an ignition problem?

Any suggestions are appreciated.

oldcutlass

A lot of times a back fire is due to excess raw fuel in the exhaust system.

Tedd Thompson

Could be the harmonic balancer or timing chain has gone south. I would not think one tank of fuel is the problem.... Tedd

btw

I thought the same since I just drove the car Monday evening with no problems. Excessive fuel in the exhaust will burn and I don't wish to drive a flamethrower.

I'm guessing top of my head it's either the fuel filter or the fuel pump which is where I'll start when I get home tonight. While I'm asking questions - Tedd, how would the timing chain be involved?

Tedd Thompson

If the timing chain has slipped you timing will also be off. There is a good chance that one or more of the eight plugs are firing on a open valve.

Does your engine turn over faster or sound differently than what it did before your backfire? If it does it could very well be a bad timing chain and there will be a loss of compression on the cylinders that have open valves.... Tedd

m371961

I assume it ran ok after the new wires. Don't see it being fuel filter or pump. How many miles on engine? Exhaust backfire is either timing or as said above,or unburned fuel in exhaust.

btw

Update: no more backfires but the engine won't start. I charged the battery to 100% (it was at 70%) and plan on buying a new battery. The engine turns over but dies as it sounds like it isn't getting any fuel (fuel filter, carb or fuel pump?).

This past April 2016 I changed out the old spark plugs with new plugs and wires, rebuilt the starter, new belts, new timing chain, and replaced the points with Petronix ignition. I've driven 1000 miles since April to shows and many trips. The engine has 31000 miles and is straight original, as is the rest of the car.

steverw

Can you see two streams of gas in the carburetor from the accelerator pump inside the carb when you work the throttle linkage from under the hood? Ethenol is good for nothing, perhaps if your fuel pump is older the ethenol finished it off. Cracked distributor cap?
Good luck

oldcutlass

You need to make sure you have fuel and a strong well timed spark in order for it to start.