As the title says, my throttle body doesn't like to close after I spray my car. Nothing is hitting the linkage or cables, and it only does it after I spray my car. Unless I open the throttle and let it slam shut, it stays open 1-2%, and on a 58mm tb that causes it to idle pretty high. Any ideas what causes this?

 

Try dabbing some oil on the butterfly rod where it enters the body of the TB. My idle was hanging after I cleaned my TB and oiling it solved it.

 

How long after you spray it does it do that?

 

For about 15 minutes

 

TTT, Does anyone know what causes this?

 

is the throttle body coolant lines hooked up?
if not, you might wanna, your throttle body is freezing up.

 

If you have one of those BBK/Edelbrock TB's then it's the actual flapper valve mechanism that is slipping. Mine does that. You have to tack weld it so that it's firm and doesn't slip. Check the part that the throtte cable is connected to. The cam actually is what it might be called. The part that the throttle cable connects to and also to the flapper valve shaft. It slips and spreads apart when slamming the throttle open. Test by opening the throttle from the cam by hand and see if it slips. that's the culprit then.

hth
Karl Ellwein
Ellwein Racing Engines

 

Are you spraying in front of the throttle body? If you are, it cools the throttle body down and may cause things to stick as they contract from the cold. I wouldn't suspect actual freezing, but its worth checking as well. Dirty lubricant on the shaft bearings could also get more viscous as it cools down.

I spray a dry 300-shot through the throttle body and never had a problem with the Holley 58mm TB sticking, but I know there's a good clearance between the blades and the bores. Also sprayed a dry 150-shot through the stock TB and never had a problem.

 

Yeah, but its only a 125 shot. And if it froze I'm sure it would unfreeze right away, not 15+ minutes later.

 

It only does it after I spray it, other than that its fine 100% of the time.

 

snowmobiles are notorious for doing this especially if you are in really cold conditions. that is why some machines have heated carbs/throttlebodys.
For your problem, you really want to check is your throttle body is clean because if it is oily and dirty nos will make the oil thicken up and freeze.
remember, nos is very cold when it's sprayed and if things are not just right it will cause all kinds of problems.
check to make sure your throttle body is not worn out.

 

The throttle body is a month old, and it's not freezing, I parked my car for 5 minutes which is more than enough time to heat it up after my last run before I drove home, and it still did it for the first 15+ minutes on the way home from the track.

 

Did you ever have any problems with it before you got the new TB? If not swap TB's and see if it goes away. You might try to clean it really well, including the IAC, and lube it and then spray it right after to see if it still does it. Not really sure at this point what would cause your TB to stay open only after you spray it.

 

Do you understand that the parts in the TB contract when they get cold, and since come parts are aluminum and some are steel, they contract at different rates, possibly causing them to bind. And I've had ice on my solenoids after I sprayed. Nitrous absorbs a huge amount of heat when it changes from liquid to vapor phase.

Its just a suggestion on something to consider.... if it annoys you as much as it seems to, I'll drop it.

 

It would be pretty easy to check. At the track take a little propane or butane torch and after it does it, just warm up your TB for a few minutes and see if it goes away faster. Either that or just temporarily hook up your TB coolant hose if you still have the connections for it.