Hey all! I diched my edelcrap since it was having issues at the track and I had this new holley sitting in the garage collecting dust. Major improvment and got into the low 14's, 14.2@98 was the best which makes me happy since the edelcrap would just screw up I couldent do better the 16.00 but it ran perfect on the street.

Anyway under transistion from light cruise (feather touch) to slightly more throttle I get a hessitation then it picks back up. It acts like I need a larger pump nozzle it has a stock 25 in it now but its hard to say for sure. Any suggestions would be welcome before I go buy parts to test with since $$$$ is very limited.

 

If it hesitates with quick throttle action, it's accelerator pump. If it hesitates with gradual throttle action, it's power valve - need a higher #, yours is probably 6.5, a 7.5 would probably do the job.

 

You know thats what I was thinking but manifold vacuum drops on tip in to around 4ish. to be honest it's been soo long since ive had to mess with a holley ive been second guessing myself alot. 3 years is a long time.

I do have an 8.5 PV that I picked up a few days ago, think that would be too much? Vacuum is around 16-1/2 at idle in drive current PV is a 6.5.

 

8.5 may be too much, but it should solve the problem.

 

Thanks for the reply's 57!

Well got the new 8.5 in and its a little better but still there between 0-1/4 throttle. The car is more responsive overall but still has some hessitation. While driving the vacuum guage seems to drop from 10 to 5 when this occurs just like 5" of vac dissapers. Its got me kinda confused.

 

Well I put in a #31 nozzel and it helped alot. It's about 99% normal with the nozzel and PV swap. I think it might need a little more on the shot but it"s good enough for now. Just gotta wait 3 weeks before i can go out to the track to see if it can be tunned into the 13's that would be nice.

 

Check the primary side accelerator pump linkage - there should be no slack at all in the linkage anywhere, from the throttle lever/pump cam to the arm on the fuel bowl. It should not be 'tight' per se, but there should be no slack in the linkage. Adjust the screw/spring setup sitting on top of the accelerator pump arm on the fuel bowl untill the slack is gone. When you move the throttle lever even a little bit, it should move that linkage and you should see some fuel squirt into the primary throttles.

This tripped me up for about 2 weeks, when I had the same problem you describe years ago when I was learning to tune my first Holley (a #3310 750cfm vac secondary). Adjusting all the play out of the linkage solved it for me.