massive hessitttation

i have a 69 gto with the 400. i just finished restoring the car. i put a new distributor in it which is timed around 12 degrees. i had the Q-jet rebuilt. the car starts great, idels great, overall runs great, but when i put my foot to the floor the car sounds like it is being choked or flooded. with my foot to the floor it does this for a couple seconds, then it screams to life and really takes off.
what is going on? is the secondarys opening to early?, is it the timing? any help would be great

to me it sounds like vaper lock .or your floats are not set right check your floats and also might want to add a heat shield between carb and manifold .might be to much heat between the 2 ...... quads and GMs are famous for that hope this is of help



travis williams

If you start the car and let it warm up a little and then open the four barrel, its not vapor lock. I highly doubt its the floats either, because even if the floats were not set exactly right with it idiling it would fill the bowls with enough fuel to open the four barel several times. The first place I would start is with the carb itself. q-jets are a good carb if you have one that works and preformes properly, but most people experience the same problems with them that you are having. Who rebuilt the carb? Take it to someone who knows and uses quadrajets, these are the ones who know how to make them work properly,and can help you work out the bugs. But to be sure it is the carb, ask a friend or someone you might know who may have another q-jet or a holley who isn't having the problem your having, ask them to try their carb on your car. Good luck and lets us know how you make out.

I have had close to the same problem before. Kind of sounds like the same situation. Hesitated start but goes good after that. Sounds to me like the accelerator pump in the carb needs rebuilt....again. So get that carb checked out. Good luck, hope I helped...

Another area to check is dwell angle. I had same problem, and set dwell...problem gone!

The Q-Jet has a vacuum operated dash pot that prevents the secondaries from opening until there is sufficient fuel and RPMs. If the dash pot is not hooked to the proper vacuum source it will allow the secondaries to open to soon and cause the engine to bog down.

Ben



1970 GTO "Judge" Ram Air III, manual trans