Need a TPS.. - Honda Prelude Forum

LudedudeSi · 02-15-2003, 02:44 PM

Ok i replaced my radiator the other day and the guy that put it in said that the idle is surging because of the TPS.. He sounded posative that this was what is causing my problem. How much are these things from the dealership or is there anywere online to buy them? hard to install?? thanks

Absolut · 02-15-2003, 02:52 PM

Go to a junkyard and grab just the sensor.

Honda doesnt sell a TPS, they only sell the TB with the TPS attached for $380.

Try adjusting the TPS, my idle was surging after my swap, the I was messing with the TPS and it stopped.
You have nothing to lose but adjusting the idle and TPS, try it before you buy anything. Good luck.

LudedudeSi · 02-15-2003, 03:07 PM

When i got the motor swapped the idle was doing what its doing now. my mechanic thought it was the iac and put the one from the h23 in it. he lowered the idle so it went away then it came back like a month later. the idle as screw is as low as it will go. i ordered another IAc thinkin it would fix it and it didnt. then checked for vacuum leaks and couldnt find any. i recently replaced the radiator and its still bouncing. i dont really understand how you can mess with a tps. its just a lil plug. anyways i dunno what to do about this now.

Absolut · 02-15-2003, 05:13 PM

Its a rheostat. A varible resistor.

When you press the pedal and the throttle opens up, it turns the TPS variying the resistance. If the TPS is in the wrong position, it wont read idle, or WOT. ex:

(These arn't actual spec, just an example)

Throttle closed TPS might read 0 ohms
WOT might read 10k ohms

But your maladjusted TPS reads:

Closed = 1.5k ohms
WOT = 15kohms

Your ecu wouldnt ever see your throttle as being closed, but it sees lots of vacuum from the MAP(mass air pressure) or enough vacuum to trip the IAC circuit. The ECU might think that because your foot is on the gas(or so it thinks) that it needs to andvace some timing, and turn off the IAC(ECU doesnt think your ideling) but it still has a bunch od vacuum from the MAP sensor and gets confused, backs off the timing and enable the IAC.... thus the surging idle.

Adjust your TPS first. 2 hexhead screws hold it to the TB, losen them and turn the whole sensor back and forth til something happens.

Zelude · 02-15-2003, 07:10 PM

i had the surging problem too after swap.. i tried everything, didn't help..so eventually..i tried replacing the jdm throtle body with my si's throtle body, it worked..the surging problem went away..my car now runs fine and idles fine.. i just want to give you something to try, i'm not good with car stuff myself..heheh..so if you have time,,try that...

LudedudeSi · 02-15-2003, 07:44 PM

well i will try what you said but i doubt it will work. it idles very high and bounces and im getting tired of it.

Absolut · 02-15-2003, 10:55 PM

Quote:

Originally posted by LudedudeSi
well i will try what you said but i doubt it will work. it idles very high and bounces and im getting tired of it.

Mine did the same thing after my swap, I am using my Si TB.
Fiddleded with the TPS, now it works.

LudedudeSi · 02-16-2003, 12:00 AM

Traded the si TB to that yellowh23a guy for a nitrous pressure gauge and never recieved it.

anyways i guess i need to find another tb.

4bidden · 02-16-2003, 01:25 AM

That guy is selling some stuff over on another board right now, the yellowh23a guy.

4bidden · 02-16-2003, 01:28 AM

Here ya go....contact him man, thats not cool that he ripped you off!

http://board.hondasociety.com/showth...threadid=76956

prelude styl · 02-16-2003, 01:57 AM

I'm almost positive it's your TPS that's causing your problem, and you guys are right, adjusting it will make it go away, but, you don't just fiddle with it or move it around till it stops... well I mean I guess you could, but technically what you're supposed to do is use a multi-meter to adjust it. You loosen the 2 hex bolts, tap the multi-meter into the 2 wires of the TPS, and adjust it till you hit a certain resistance. I forgot what it was at the moment, I'll get back to you on it, but that's how you're supposed to adjust it.

4bidden · 02-16-2003, 02:40 AM

.45V at idle and 4.5V at WOT sound right?

LudedudeSi · 02-16-2003, 12:35 PM

Lets hope this fixes it. i dont have one of those meters. are they expensive?? i may just get someone to do it for me. oh and i doubt even if i contacted him he would send me anything. but anymore help would be great guys because i need to get rid of this problem. thanks

concLude · 02-16-2003, 04:45 PM

sweet, my idle has been nuts since the swap, bouncing around everywhere, so i'll have to read this when i get my car back and check into it, let us know what happens ludedude

prelude styl · 02-17-2003, 05:52 AM

4bidden, that sounds about right.

As for multi-meters, you can pick one up at a local car parts store (Pep Boys, Auto Zone etc...) for like $20 for a basic one. And they're used for a lot of system checking, wire tracing, etc, very useful if you work on your own car.

19924ws · 02-17-2003, 09:54 AM

There is a bunch of things it could be:
1) Vacuum leak
2) Air in coolant sys
3) Idle air control valve
4) Air boost valve
5) Cold start valve (broken or out of adjustment)
6) Too much tension in the throttle cable
7) Broken throttle position senor
8) Using OBD II TPS on OBD I car
TPS is Honda's standard responce bec they're gonna get 380 out of you.
1) Let the car warm up. Just let it bounce or surge and do its thing. When it is up to temp.
2) Take off the intake pipe.
3) Look in the throttle body
4) There will be 2 holes, one at 7 o'clock and the other at 9. The one at 7 is the idle bypass and the one at 9 is the cold start bypass. Getting more air helps the car heat up in cold weather.
5) Now stick your finger in the hole at 9 o'clock. This will mimmick the cold start valve closing. Don't worry it won't suck your finger in.
6) If when you stick your finger in the hole the idle goes back to normal then that is the problem.
Next, the air boost valve has a line connected to the intake pipe. Take the line off and cap it, if that stopped the idle then that was it.

concLude · 02-17-2003, 05:23 PM

lude dude, did you try this yet? i'm wondering if it works

LudedudeSi · 02-17-2003, 10:21 PM

well its not air in coolant, obdII or any of that, iac, or vacuum leaks. it could be the throttle cable or the tps. im really tired of messing with this..

concLude · 02-19-2003, 04:32 PM

did you tweak this yet? wondering if you got your idle to calm down, i've gotta fix this problem when i get my car back in april. seems to only happen when i have the AC, blower, heat, ect on....

LudedudeSi · 02-19-2003, 04:45 PM

No it has not been fixed yet. i really dont mess with it to much because its been doing this for about 2 months and ive got tired of blowing money trying to fix it. im swapping out the tps this weekend to see if that was the problem