siaxazn

i got a 93 5speed sc300 and my idle went up from the normal 600-700 to aroud 900-1250 after i cleaned the tb. I used a can of tb cleaner where you spray the whole can in with ur car running. I sprayed at 10 second intervals as directed on the can while I work the butterfly valve to keep the car from stalling.

now im thinking it was a big mistake to clean it this way and that I should of took off the tb and cleaned it like that instead and maybe i wouldnt be having this issue. but who knows.

I checked to see if i knocked nething loose while taking off the intake, i check all the vaccum hoses and they are tightly on. so i dont think theres any vaccum leak. and my ac wasnt on so that doesnt expalin the high idle. I dont know what else it could be perhaps i messed up one of the sensors when spraying the stuff in there. I even tried resetting the ecu but no luck.

For one thing the cleaner worked in cleaning the tb out, the car now runs smoother and faster. I took it for a spin around the block a few times and the car doesnt hesitate nemore like it used to..

when i start the car the idle sits at 900 when i gas and wait for the needle to go back down it goes down to 800-900 then jumps up to 1100-1200 and stays there and doesnt go any lower till i shut off the car and start it again then it goes back to 900. but thats still about 200 too high and during normal driving its 500 too high.

VSsc400

iTrader: (1)

try resetting the ECU.

siaxazn

thanks for the quick reply but i already did that with no luck.. But just to make sure will disconneting the battery for 20 minutes reset the ecu? If not then maybe i didnt reset it properly.

Woogie

yes that should reset the ECU.

siaxazn

Please give me your inputs can't seam to find nething in the forums that relate to my exact issue.

THE_CEO

has anyone done this with a sc400?....maybe i should do a search!..hehe

CEO

SupraCoup3

check your TPS (throttle position sensor) you can adjust how fast your idle is by losening two screws and adjusting the sensor clockwise and counter clockwise. Be sure to screw it back down good when you're done.

EUROJulian

Don`t do that. Have nothing to do with issiue in hand unless you touched/moved sensor during TB cleaning. There is procedure to follow when adjustin` TPS with multimeeter and stuff.

I do not know what you messed up, there are quite few things. Check vaccum leaks, check if throtle plate actualy fully close, chect ISC valve...

SupraCoup3

some people unscrew the TPS when they're removing the t-body -- that's why their idle is off, because they don't realize what it is they just removed, and reinstall the thing completely uncalibrated.


Edit: and why don't you tell us all what that procedure is if you've got the TIS at your house. The TIS system is now in Adobe Acrobat (PDF) so you could potentially upload/email it to anyone on the forum. But I'm sure you already know that.

EUROJulian

Sound like work TJ. I rub the elbows with you gentlemen and I enjoy it. Do not make me work though. It is after hours now All I can do is to offer short pointers.

I would say each and every one of you people ough to own factory manual for your car. It is only 80 bucks or so. This is a basis for not only tech disscussion here but any wrenching under the hood. I would engage in exchange on interesting topics with anybody on the book level and up.

siaxazn

I never touched the TPS when i did the cleaning cuz i didnt remove the tb. The onli thing i touched was the intake and the butterfly valve. Im thinking maybe i got some tb cleaner in the hole before the tb plate and screwed up a sensor. as i've done this procedure before on a mr2 and a civic and it worked fine. For the mr2 i had to plug up a hole to prevent any cleaner from getting in there, i didnt do that for the sc cuz the throttle plate was so deep in past that hole. Both of my previous cars had idle adjustment screw but i heard the sc doesnt have one, maybe i read wrong since you say it can be adjusted with the tps.

When i looked in the tb it looked dirty as hell and what brought me to clean it in the first place was the fact that the car was running a bit slugish, the cleaning did wonders but left my idle a bit high my car just rolled over 180k so it could get pretty dirty if the previous owner didnt take care of it. From what i know a dirty tb will cause low idle and my idle was normal. Im thinking perhaps the previous owner adjusted the tps to raise the idle since such a dirty tb should most likely have caused low idle. And now that i've cleaned it should have raised the idle up above normal if the previous owner did adjust the screw to raise the idle. But thats my thoughts and if no one has any idea what else it could be im gonna go on this theory and see where it takes me.

supracoup3 i wasnt exactly sure of your instructions on adjusting the tps. Do you mean you can rotate the whole tps clockwise and counter clock wise when you loosen the 2 screws? im only experienced with tb's where you adjust a single screw.

thanks for all you inputs keep em comming.