Starting Issue

[Hudson37j]

68 327/350 Starting Issue

My 68 327/350 engine has developed an issue that I'm trying to diagnose. Cranks fine and will catch briefly but dies almost immediately. Have replaced fuel, filter and plugs but still experiencing the problem. Appreciate any suggestions / input.

 

[Antz81]

Have you been able to get it to run (and stay running) at all since this started?
I assume you've checked the choke is closed properly.

 

[Hudson37j]

The choke is operating properly (recent cab overhaul.) The motor fires and acts like it is going to run but dies after a few seconds.

 

[Tom Bryant]

It sounds like it is running out of fuel. Do you have a strong squirt from the accelerator pump? Hold the choke flap open and cycle the throttle lever while looking down the primary side of the carb (engine off). If it's weak or stops squirting before you have done a full stroke it could be that the float bowl is low on fuel. The needle may be stuck in which case rapping on the side of the carb with a screwdriver handle should jar it loose.

It could also be the fuel pump. Take the fuel line loose at the carb. Slip on a length of rubber fuel line and put it into a milk jug. Then crank the engine for a few seconds and see how much gas is pumped into the jug. It should squirt a strong stream each time the pump cycles.

These are the first two things I'd check and they don't cost anything to do. This assumes that there is gas in the fuel tank.

Tom

 

[Hudson37j]

Thanks Tom, much appreciated! Will perform the test today and note results.

 

[Jkot55]

I am new here and new to corvette ownership. I have a 69 with similar symptoms. 350/350. I will try what you suggested but if the problem is the fuel pump can it be replaced with an electronic pump? I am assuming these have mechanical pumps. Is there kit for this conversion?

 

[Hudson37j]

I am new here and new to corvette ownership. I have a 69 with similar symptoms. 350/350. I will try what you suggested but if the problem is the fuel pump can it be replaced with an electronic pump? I am assuming these have mechanical pumps. Is there kit for this conversion?

I too am new here and have appreciated the support and follow up. Still working on the starting issue I described above...will post any positive results when I track down the issue. (Currently out of town so it will be next week before I can get back to it.) I'm not sure about your question regarding electric fuel pumps but will do a little research and see what I can find.

 

[GTR1999]

My 68 327/350 engine has developed an issue that I'm trying to diagnose. Cranks fine and will catch briefly but dies almost immediately. Have replaced fuel, filter and plugs but still experiencing the problem. Appreciate any suggestions / input.

Check your basics, this engine is the same as all 1st gen SBC. Air-Fuel- ignition. As mentioned with the car off, open the choke plate and move the throttle- you should see a strong stream of fuel coming out. Check the distributor, points and condenser.

 

[Antz81]

I am new here and new to corvette ownership. I have a 69 with similar symptoms. 350/350. I will try what you suggested but if the problem is the fuel pump can it be replaced with an electronic pump? I am assuming these have mechanical pumps. Is there kit for this conversion?

If it does turn out to be the pump, I would stick with a mechanical pump rather than going electric. The mechanical pumps tend to last a lot longer.

 

[toobroketoretire]

The fuel pump should squirt out 1-1/2 pints of fuel in 30 seconds of cranking. If it doesn't produce that much either the fuel pump is failing or.........................

 

[SVO]

I'm going to go in a different direction - have you checked to see if the resistor wire to the coil is good? You have two wires that go to the positive post on the coil. One wire is non-resistor wire and supplies 12 volts to the coil for cranking when the ignition switch is in the crank position. The other wire is a resistor wire that supplies 7-8 volts to the coil when the ignition switch is in the run position. The resistor wire drops the voltage to keep from burning up the points. So if the resistor wire to the coil is bad, the car will crank and run momentarily until the ignition switch moves to the run position. Then it dies. A wiring diagram should help you sort it out.

 

[toobroketoretire]

Okay, now I'm going to go in another different direction. The breaker plate inside the distributor has a braided copper ground wire and it's very common for that wire to break after being flexed a million times. It's possible for that wire to make contact when the breaker plate is swiveled in one direction but loses contact when the vacuum advance gives it a tug in the other direction. And check to make sure the braided resistance wire is connected to the + post of the coil along with the 12 volt wire that goes to the R terminal of the starter solenoid. If you had those two wires disconnected recently you may have forgotten to put them BOTH back on.