So I've had this thing for a while now and I would like to get my car running right.

Its actually a NOS 58mm TB, its basically the same as the Holley except it has nitrous passages.

First if all it sticks when trying to ease on the throttle and it will jump when you finally do accelerate. I didn't used to have this problem, but for some reason i do now.

But the real problem is the blades wont close completely while the car is running. It will hang up around 14% throttle. When the car is off it acts normally, no binding at all. But as soon as i fire it up, all these problems appear. I have to blip the throttle to get it to close more. I have drilled out the IAC passage and have adjusted the TPS to .64 while the blades are closed.

So if anyone knows a fix to this thing, your help would be greatly appreciated. This problem is making my car no fun to drive anymore.

 

typical problem. I only had the second problem and an extra throttle spring fixed it. once it "breaks" in the blades wont stick. the problem is the blade and hole tolerances are jsut to tight and it takes some miles to wear them down..... jus crappy quality control..... once the blades wore down mine worked fine

 

Can you post a picture of the helper spring? I thought of using another spring but couldn't figure out how to hook it up.

I sanded down the blades so that there is no contact with the throttle body, and i lubed up the shaft so everything should be good. It only does it while its running, so I'm thinking that its vacuum related.

Anyone else have any other input?

 

I've never had a single problem with my Holley throttle body...Once I adjusted the cruise control cable.

Frank
CPT

 

Are you aware you can adjust the tension in the Holley spring by moving the end of it to a different hole in the body?

 

My Holley 58mm TB is one item that has been completely trouble-free for me. Having said that, I hope I didn't jinx myself.

WD

 

Yes, I have tried the 3 holes for the spring, I even tried a setting that tensioned the spring more. None of them would get the blades closed completely.

I also adjusted the cruise control cable to tighten up the extra slack and it still wouldn't close properly.

 

Have you removed the cables from the TB to make sure those items arn't the issue holding it open?

WD

 

I never had a problem with the spring, or with the blades fully closing. The blades had such large gaps around them that they rotated freely. I actually had to "enlarge" the blades slightly to get the IAC to read where I wanted it. Also had a problem with the metal bar that hits the throttle stop screw. It would rotate slightly in the aluminum quadrent, making the TPS voltage a bit erratic. The bar had to be pinned to the quadrent.

 

I only have the single cable to the throttle body and it moves freely while the engine is off, but as soon as i turn it on, it starts hanging up.

 

i had the same problem and the guy who tuned it for me(sra performance portsmouth ,RI) fixed it what he did is took it off the car and you have to take a fine peice of sandpaper and sand a little at a time either the blades or the whole itself it may take 2-3 times of installing and uninstalling to get it right i think i have a .010 clearance now sometimes it does stick so i actually need to do this 1 more time it does work but DONT TAKE TO MUCH OR IT WILL NEVER BE RIGHT nice #'s on the mustang dyno right.

 

Is it the engine vacuum pulling, or holding the butterflies shut while it is running? Possibly adjusting them slightly open, then allowing IAC to do the rest.

WD

 

I have sanded down the blades so there is no contact. So I'm sure thats not the problem.

I'll try a helper spring to see if vacuum is a problem. Its open so much that it idles at about 1000 rpm. But it is definitely hanging up on something, i just don't know what.

 

Have you had a backfire, it can really screw-up the shaft and blades. Sticking coming off idle is a symptom. Danny Mc

 

I know how to fix it..................


Ok I'll tell ya. Loosen the screws on the red throttle blades just enough so they will adjust themselves. Then with the engine running blip the throttle a few times until the butterflies center them themselves. Shut the car down and tighten up the screws.

I had the exact same problem and it fixed it. Now you can move that spring back to middle hole because it won't need much spring pressure to close.

The problem is that the butterflies aren't adjusted with vacuum applied from the factory and they stick open.