surging idle ?

[Zrain25]

my new to me supra. has idleing issues. i had 5 codes when i bought i dont have any now but when i turn the car on it idles at 1500 and will for like 3 minutes then it will start to surge from 1500 to 1000 and i will keep doing it. it drives fine it dose have some turbo surge but other then that it drives good im just haveing idleing issues and its not throughing any codes?

any ideas on what would couse the idle to be so high and surge?

 

[Zrain25]

i did some searching around and i found out it might be the idle cotroll valve needs to be cleaned. but i dont know where it is located on the engine or how to clean in. im guessing its near the TB.

and another note my idle is sometimes fine it will idle at 800 sometimes. then other days at 2000 rpms. its starting to get me mad lol

 

[IndigoMKII]

Have you checked the TSRM in regards to erratic idles?

 

[jetjock]

It might even reveal where the valve is located...

 

[Zrain25]

what the tsrm? sorry im new to the forum is that the search? and yes i did try it but i didnt search eratic idle. i will try now

 

[hvyman]

Tsrm = Toyota supra repair manual
Epc = electronic parts catolog
Ewd = electrical wiring diagram

http://www.cygnusx1.net/Supra/techtips.aspx

 

[Zrain25]

ok update i took out the idle air control valve. the thing that spins to open and close the valve was a little hard to spins. i put some wd 40 to get some of the rust out and it spins good now. i put it back on still high idle but no surging. just holds tigh at 1600 then i tried to adjust tps and got it down to 1400 rpms. it will hold at 1400. when i unplug the tps the car just to 1900 rmps. oncei plug it back in it goes back down to 1400 rpms?

any ideas what it could be now ?

thanks
>

 

[IndigoMKII]

ok update i took out the idle air control valve. the thing that spins to open and close the valve was a little hard to spins. i put some wd 40 to get some of the rust out and it spins good now. i put it back on still high idle but no surging. just holds tigh at 1600 then i tried to adjust tps and got it down to 1400 rpms. it will hold at 1400. when i unplug the tps the car just to 1900 rmps. oncei plug it back in it goes back down to 1400 rpms?

any ideas what it could be now ?

thanks
>

Sounds like the electrical timing is off, adjust the CPS in regards to the TSRM.

 

[Zrain25]

today after i did some body work on it. i started it to take it to the back yard to wet sand and it started at around 900 to 1000 rpms and stayed there? it does this all the time sometimes it will idle at 800 and sometimes 1400 idk what it its im leaning toward tps.

and i also heard you cant time the engine when you idle is off?

 

[IndigoMKII]

today after i did some body work on it. i started it to take it to the back yard to wet sand and it started at around 900 to 1000 rpms and stayed there? it does this all the time sometimes it will idle at 800 and sometimes 1400 idk what it its im leaning toward tps.

and i also heard you cant time the engine when you idle is off?

My electrical timing was off and caused the car to idle higher, when I started bringing the CPS closer to 10 degrees, the idle lowered and the idle also became more stable.