just bought a 78 corvette, runs great and interior is very clean in great condition, does have a few problems that I was wondering if they were common. First off the speedometer bounces around, it is fairly correct but when the rear tires bounce it moves all over the place, was wondering if the cable was loose or something. Another problem is you can not floor it, the motor just doesnt move, the rms drop and you dont get any power when youpush the pedal to the floor, but going into the accelerator smooth it runs great. Any help would be great, I am looking forward to my new corvette life and meeting more and more of you.


thanks.

 

Hello, Welcome to the site and Congratulations on your "New" 1978 Corvette!

As for your speedometer, usually the speedometer drive cable gets worn out and causes a jumpy needle, but you say yours bounces when the rear wheels bounce..... I would try removing the speedometer from the dashboard (it comes out with a phillips head screwdriver, remove the lens first, then the speedo/tach) and cleaning it.
As far as the lack of power is concerned, it sounds like the vacuum advance on the distributor is not functioning. Our Corvettes are also notorious for vacuum leaks which can contribute to poor engine performance and slow or no movement of the headlight doors. You may also simply need a good tune up or the accelerator pump on the carburetor may be worn out.

I hope that helps!

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Hi danmfo5, can you tell us what carburetor your Vette has? The factory Quadrajet has a number of fine adjustments and someone may have modified them, this could lead to poor performance. Get back to us, we'll have 'ya running good in no time.

 

How about the "accelerator pump" not working? That will cause it to fall on it's face when you stomp it, no?

 

everything is stock for the car, so i would guess that it still has the quadrajet carb on it, i just got a repair manual so i will have to check out the accelerator pump, would it be a cracked vacuum line or something like that? thanks for the help so far

 

Hope the manual you got was the Chev. service manual as it details the rebuild of the Q-jet. Since you'll have to take it apart to check/replace the accel. pump anyway, you might as well do a rebuild.

 

Hi danfo05 and welcome to the forum! I agree with the previous posts, you may have a problem with the accelerator pump. It's in the carb, with the air cleaner off and the car in park with the parking brake on, remove the air cleaner and blip the throttle, you should see 2 streams of gas being shot into the carb. The linkage may have fallen off or be out of adjustment or the accelerator pump may be bad. If you don't see those 2 streams of fuel get a rebuild kit, using the # on the side of your carb, it's a quick, easy and cheep fix. PG.

 

thanks for the advice, i was thinking about just replacing the carb all togetherto get something more updated with current technology...any suggestions or is this a bad idea, im hoping to replace headers and such also to get a bit more power out of the motor...

 

The Quadrajet is a very good carburetor for your engine. Have it rebuilt and spend the money you saved on some other improvements for your 'Vette.

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Excellent idea.