I recently upgraded from the stock 48mm throttle body to a 52mm throttle body and I was wondering, do I need to put a different TPS on the TB? When installing I just put the stock one on the new TB. But since the install my car has been shifting really oddly and I've had my SES light come on a few times while flooring it. Made the car shift from 1st to 3rd or something... it's really weird. If anybody can help me out here, I'd really appreciate it.

ps: I rerouted the coolant line from going into the TB and the metal clamp was laying against this sensor. That might have caused a problem, too. But since I found that out and tied it to the alternator, the car has still been shifting funny.

Thanks,
Steve

 

You should check your TPS operation with a scanner.

 

Took it to my mechanic and he said it threw a code. He's not sure if I need a new TPS on there though, since I still have the stock one but not the stock TB

 

I had the same exact problem when I went with a BBK TB. No, you do not need a new TPS, so don't buy one like I did. You need to use a digital multimeter and test the millivolts (or whatever measurement the TPS uses). I think I recall the readings should be between -.040 and -.090. something like that. It all has to do with the positioning of the actual sensor. You need to drill two "rails" for the TPS to be adjusted on and move it around while the motor is running. There is a thread in this forum that shows you how to do so. Hope this helps.

 

Thanks for the info, I'll check that out. And it is a BBK that I have, so it probably was the same problem. Did your car shift much differently after the install?

Steve

ps: I couldn't find any posts about repositioning the TPS. Is it pretty simple to do?

 

well, I'm 100% sure now that you said you have a BBK like me that the position of the TPS is causing your weird problem. I can't believe there are no other threads about this. Well, when I said you needed a multimeter to measure the TPS voltage readings, you also kinda need a TPS testing kit. You can either make one your self (I don't recommend this route) or buy one like I did ($25 off of ebay). Once you have the test kit and a multimeter, good luck trying to get the TPS positioned perfectly. You'll need patience and one other person's help (probably). You can only measure the readings at WOT, which you'll have to pull the throttle cable to do so. Make sure the car isn't running.

P.S. On a quicker note, you can do what I'm doing and buy a thunder racing stock ported TB (52mm) because the TPS rests in it's little "seat" so it can't have moved and fugged up our TPS codes and all. You and I could easily sell our BBK TB for enough to cover a thunder racing one.

Good luck man, e-mail me if you need pix of the TPS testing kit.

-Tony

*EDIT* you asked me if I had shifting probs, I have a 6 speed, so, not really.