Install New PP Throttle Body, Car Runs Like Crap!

rickbtbird

Registered User
Install a Professional Products Throttle Body today, now the car runs like crap. I don't know what's going on but it acts like I have a large vacuum leak in the intake.

First issue I ran into was in the instructions. It says to adjust the Idle speed screw counter clockwise until the throttle body butterfly is fully closed Then continue to turn it until you get .010 clearance. Once done, turn the screw clockwise one full turn. If you follow those instructions the throttle sticks because the butterfly hits the TB throat and slightly jams. I have to turn the screw another 1/4 turn to get the proper clearance.

The second issue (which is the biggest) is after adjusting the TPS to .925 volts I start the car and it idles was up in the 2k rpm area way to long. Then after about 15 seconds or so it finally drops down to about 750rpm. If I rev the motor it hangs in the 2k rpm area again and then drops. It makes the car very un-drivable.

Anybody know what's wrong? I had to fall off the new TB and go back to stock.
 
Have the same TB and don't have any of those symptons.

Did you adjust the IAC bypass screw? Its the screw that is on housing that the IAC valve screws onto. You need to screw that all the way in (don't force it) and back it off about half a turn or so. Unplug the IAC and start the car up (you may need someone to feather the throttle to hold the idle at first) then adjust the IAC screw until the car is idling around 500 or so and sounding like its about to die on you. When it can hold its own shut the car down, and plug the IAC back in. You should be good to go for the most part.

Right now its allowing way too much air into the motor hence the reason your seeing that high idle situation. The other screw on the other side is just to setup the throttle stop position. It is not meant to adjust idle.

Have you rounded out the inlet where the throttle body bolts onto? If you haven't you could end up losing performance over the stock TB because of turbulence.

Frit
 
Have the same TB and don't have any of those symptons.

Did you adjust the IAC bypass screw? Its the screw that is on housing that the IAC valve screws onto. You need to screw that all the way in (don't force it) and back it off about half a turn or so. Unplug the IAC and start the car up (you may need someone to feather the throttle to hold the idle at first) then adjust the IAC screw until the car is idling around 500 or so and sounding like its about to die on you. When it can hold its own shut the car down, and plug the IAC back in. You should be good to go for the most part.

Right now its allowing way too much air into the motor hence the reason your seeing that high idle situation. The other screw on the other side is just to setup the throttle stop position. It is not meant to adjust idle.

Have you rounded out the inlet where the throttle body bolts onto? If you haven't you could end up losing performance over the stock TB because of turbulence.

Frit

Yea it was fully shut out of the box and I tryed to adjust it but the more I opened the valve the more idle RPM's I got.

I didn't port match the TB to the inlet as I only have one inlet right now and I'd rather not damage the only one I have.

This car was just reassembled about three weeks ago. I don't have any vacuum leaks that I can find. I'm running about 18-19hg at idle with the stocker TB.
 
Open the TB up so you can see the edges of the butterfly... is it clean and smooth along the edges?

Frit
 
check the IAC screw isnt way open. theres nothign there that can eff the car up that you cant adjust. u need to play with it a bit.
 
I had the same junk. My car also ran like ~~~~ after i installed it. I did a pressure test to find any leaks. And i had a leak from the throttle leakage. I took it off and is now on my self. Waste.
 
the throttle linkage thing is held on by vac. its not meant to be pressurized. adjust your Tb the thing works u just need to set it up right.
 
The idle speed screw was set per the instruction and the IAC screw was bottemed out letting no air in. The TPS was at .925 after adjusting it. Serioulsy, the car runs like it has a major vacuum leak. I pulled it off and put the stock TB back on and the car runs normal now. I'm going to vacuum test it off the car with the shop vac. Also, if you open the IAC screw doesn't that allow more air in the system increasing the idle?
 
Set up the throttle stop screw (its not an idle adjustment screw, thats what the screw is on the IAC) per spec and see exactly where it is binding inside the TB, then touch up the edge of the butterfly with some fine sandpaper to remove the binding... do not remove alot of material.

Your right about the IAC screw, it allows more air in so you can setup your base idle.

Also, double check the gaskets both for the IAC and the TB to inlet plenum. Make sure those are the right size.

There is nothing wrong with these TB's, and it only takes a bit pf patience and time to get them set up... just like any other car your modding.

Frit
 
Set up the throttle stop screw (its not an idle adjustment screw, thats what the screw is on the IAC) per spec and see exactly where it is binding inside the TB, then touch up the edge of the butterfly with some fine sandpaper to remove the binding... do not remove alot of material.

Your right about the IAC screw, it allows more air in so you can setup your base idle.

Also, double check the gaskets both for the IAC and the TB to inlet plenum. Make sure those are the right size.

There is nothing wrong with these TB's, and it only takes a bit pf patience and time to get them set up... just like any other car your modding.

Frit

In its current state I don't see how it could work. The ad said it was for the Thunderbird SC and I got instructions for a Mustang 5.0L setup. When I purchase something that’s suppose to be for our motors, I don't expect to have to machine the tolerance of the butterfly to a different specification to make it work nor am I satisfied or thrilled with the instruction for the TPS adjustment. It seems to me that this company manufactures these for the Mustang V8 and couldn't move them off the shelves quick enough so they decided to offer them to the Thunderbird SC 3.8 Super Charger setup but it doesn't actually work as they said it would. IMO it just isn’t prudent.
 
Professional Products = Un-Professional Products


At least thats what everyone on the mustang boards says! id stay away from the garbage they make there! from what i understand a tb upgrade doesent do much of anything for our cars OR mustangs anyway...
 
Upgrade wise, unless your getting a bigger inlet plenum etc, it's pointless for the most part.

As for the TB... I must of got a rare one then :rolleyes: because I've had no issues with mine. Followed the instructions to the T and adjusted the TPS voltage and the IAC valve and its been singing a song ever since.

Plug-n-play on an SC.... you've got the wrong car if you think thats gonna happen.

Frit
 
>As for the TB... I must of got a rare one then because I've had no issues with mine.

Good point. How long since you installed yours?

I wonder if both of you should compare part numbers, as an example...might shed some light.

>Plug-n-play on an SC.... you've got the wrong car if you think thats gonna happen.

'nother good point :)

More like plug-n-pray...
 
all right this may seem dumb ... but block the idle air controller right off ..make a gasket and put it on ...blocking the holes ...and you will know soon if you have a leak ..... adjust the idle via throttle body screw ...and work from there...dave
 
I had the same problems with mine and I messed with it quite a bit. I ended up closing the large TB screw all the way clockwise and now it runs fine. The only issue I have is that it sticks when you first step on the gas. I port matched my 94-95 inlet plenum to the TB and smoothed out the transition into the inlet.
 
When I installed my PP Throttlebody, I had to do all the same adjustments as you have. I also needed to un-hook my battery for a short period of time to reset my ecu. Give that a shot and see if it helps.

Mike
 
Ok, I'm game, part number I have is 75mm TB T-bird SC Polish #69232.

Frit

The box says 75mm Throttle Body T-bird Super Coupe Satin 69233. There's a label on the TB itself that mentions it could be either 69232 or 69233.

Fritz, explain to me again how sanding down the butterfly would be beneficial.
 
When I installed my PP Throttlebody, I had to do all the same adjustments as you have. I also needed to un-hook my battery for a short period of time to reset my ecu. Give that a shot and see if it helps.

Mike

Yea battery was disconnected. TB Idle Screw was set, TPS was set, ran like the car has a large vacuum leak or disconnected vacuum hose. Adjust the IAC screw and it got worse. Put the old TB back on and it runs normal. My guess is, one of these three.
  • The TB is too big for my setup.
  • There's a large vacuum leak that is exacerbated by the new TB.
  • The new lot of IAC I got are defective or meant for another car.
I remember back when I got my 90’s IAC replaced it ran a high idle similarly to this but when I put an OEM used one in its place the issue went away.

Also, I think at some point I’ll pull off the blower and check the intake manifold and the injectors again, trace all the vacuum lines and pressure/vacuum test thing one step at a time as I reassemble it.
 
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