I have a 1973 Corvette 350 ci 190 hp Automatic Transmission, starting running poorly last fall, so this spring, I changed the points, plugs, wires, rotor, condenser and cap, still running poorly. So I tested and found the coil was not firing all the time, replaced it, new coil not working either, purchased another coil and car started up, still not running real good. I replaced the original Quadrajet Carburetor, with Edelbrock 1406, runs great, but then starts running bad again, while in the garage, runs great, revs up great, take it out for a ride, runs great, then starts missing and running poorly. Limp home, park in the garage starts running great again, take it out, same issues. I took the distributor out, cleaned, oiled, changed the points and condenser again, made sure points are gapped correctly, put back in, same issue.

Drained the Gasoline and filled up with fresher Gas, same issues, fuel filter is brand new, after running, took off, drained it, looks clean, the inside of Gas Tank looks good, was replaced 11 years ago.

I notice at times when I give it gas there is hesitation, other times very responsive. The car has 130k, was sitting, not running in the weather for 10 years, prior to my purchasing and doing a partial restoration on it. Original engine and tranny, was running pretty good till last fall. I'm guessing a fuel pump? any other ideas what to check, sure would appreciate all ideas, could it be vacuum advance on the distributor? or the distributor ?

Transmission shifts fine when driving, so vacuum working correctly there, headlights open and close, wipers work, so I believe the vacuum is ok?

I'm hoping I can get some good advice, before changing out the fuel pump, and possibly still having issues, then changing the distributor, only to find out, it's actually something else. I don't mind changing things out, better to do it now, then to break down while enjoying a drive.

Would like to enjoy driving it a little this year, so far only working on it. Being older and retired, it's difficult to accomplish everything quickly on the Vette. At times, the mind and body do not agree on what and how fast I can accomplish things, I do accomplish things, just not usually correct the first time or two, oh well, just having some fun in life.

Thanks in advance

Joe

 

Check the pigtail- the lead from the points to the coil. It flexes every time the vacuum advance moves the breaker plate. They have been known to break. And check the wire from the bulkhead connector to the + side of the coil. It's a resistor wire- they can go bad too. And heat makes it worse.

 

Hi Joe,
Fuel supply under operating conditions?
I believe your 73 small block car has rubber supply and return lines running from the steel lines on the frame rail to the fuel pump.
The supply line because of it's route can get quite a sharp 'S' shape to it and even kink. This could limit fuel supply to the pump.
Perhaps you might check those rubber lines for condition and configuration.
The 'S' shape is so critical that some venders sell a hose preformed into the proper shape.
Regards,
Alan

Note the bends at the steel lines and the pump connections. The larger hose is the supply, the smaller is the return.

 

Allan, you were 100% correct, I replaced the hose, still have a small kink, but car running GREAT. I'm thinking about purchasing a spring that will fit over the hose to hold it from kinking. Actually replaced both hoses not an easy task for sure.

Thank You, Thank You , Thank You...

 

Hi Joe,
If that is indeed the 'fix'….. great!
Regards,
Alan

 

Hi Alan,

Took it out just now, put the AC on Max, was able to run around great, punched it a couple times, simply took off GREAT.

Yes, that was the issue....

Thank You again.

Joe

 

Install the correct hose

https://willcoxcorvette.com/corvette...it-front-70-82

 

After fixing the kink in the hose, next time starting the car, the fuel pump now leaks, ensured it wasn't the hoses. So I ordered the correct replacement pump and new S hose from Wilcox Corvette. Looking forward to having more fun with the Fuel Pump installation, once the new items arrive.

Joe

 

Hi joe,
This is why'retirement was 'invented' …. to ensure that you have the time needed to work on an old car.
Regards,
Alan

 

New Fuel Pump and hoses installed, while I was at it, I purchased and installed a Chambered Exhaust system. Vette is running fantastic and sounds GREAT!

Thanks to all that responded with suggestions and idea's

Greatly Appreciated

Joe