6G Celicas Forums

Hi everyone my 94 celica ST has a idle fluctuation when im in gear and have the fans on. when the fans go off i idle at about 1k. normal idle in park with no fans or accessories on is about 1.5k which I know is a issue, I replaced the fuel filter, spark plugs and spark plug wires, o2 sensor, throttle body and TPS from another celica but I dont think I aligned the TPS correctly? Do you think this may the cause? If so does anyone know how to properly re adjust the TPS sensor onto the throttle body?

https://youtu.be/mmk4e4pkoo8

Im also getting a code 25 which says "The air/fuel ratio feedback compensation vlave or additive control valve continues at the upper (lean) or lower (rich) limit for a certain period of time." And noticing this I had another set of fuel injectors that was off my old celica which ran just fine and put those on so I dont think its the injectors. Any help is appreciated.

This post has been edited by rapid36: May 17, 2016 - 11:43 AM

Have you cleaned the idle air control valve?

Hmm not sure how in depth I went with the cleaning but before I swapped the throttle body I took the throttle body off and sprayed everywhere with throttle body cleaner, Not sure If I ever took off the IAC which I think is at the bottom of the throttle body if im correct (pretty sure I did, or at least I thought I did). And then I swapped out the throttle body later with a different one with a different IAC and still had the same result. Although I dont know how detailed I need to be when cleaning the IAC, maybe I should take it off from the throttle body and give it a good cleaning again, couldn't hurt I imagine. Thank you, ill give that a try.

With the TPS you need to bridge TE1 and E1 before adjusting to whatever resistance is specified by the book I believe, I want to say the AutoZone online manual section might have the needed information. Any vacuum leaks could cause high idle as well.

Hmm, ok so cleaned out the IAC and it moves freely, and it did even before I started cleaning it, so I dont think that was the issue, however I did replace the IAC sensor with the one off the other celica and it doesn't seem to hesitate as much now, now it will do it a few times then level out then 20 seconds later hesitate a few more times and then level out again. So maybe both these sensors are bad and just need to be replaced, and I think THAT should fix my idle fluctuation, which before I go throwing money at the car I will try to test resistance and such like what you stated then if its out of spec (with TE1 and E1 terminals jumped) I will replace it with a new one.

I still have a high idle though, that part didn't seem to change at all, any suggestions on what could be causing that? I replaced ALL vacuum lines with new ones, cause the car sat for a while and wanted to make sure I didn't have a leak so I replaced them all. I still may have one and not know it, but I am not leaning towards that possibility.

This post has been edited by rapid36: May 18, 2016 - 11:56 AM

I'd check around the intake manifold, throttle body, and injectors as those can sometimes start leaking. Another thought is there's an A/C idle up circuit that has a solenoid that induces vacuum to raise the idle, so if it's stuck open and your A/C is off that could cause a higher than normal idle.

Thanks! Messed with the throttle position sensor a little and found it not to be an issue, so maybe there is a vacuum leak somewhere, ima try and look for one today after work. I'll keep everyone updated on what I find.

And just out of curiosity will a vacumm leak and a lean condition make the car loose power? cause this car doesnt have much power compared to the other celica ST I drove. I know these cars arent fast but I know mine itsnt up to par of a stock one lol.

This post has been edited by rapid36: May 19, 2016 - 10:55 AM

It won't run at its full potential with a vacuum leak, it can make a world of difference if the leak is bad enough.

Thanks!! ok so heres the update... Cleaned the IAC valve without removing the IAC valve and by spraying carb cleaner into the port on the bottom of the inside of the throttle body, I just removed the sensor part that is held on by a few screws, also had to take off the throttle bracket and then I was able to have access to the screws for the IAC valve then as I sprayed carb cleaner in the throttle body port I was moving the IAC valve back and forth, and after cleaning it, it did make a difference but I dont think the valve is able to open quite all the way, so I will be replacing it with the other IAC valve I have (which feels easier to move than the other IAC valve which is why I think the one thats on there isnt able to open all the way). Im pretty sure the problem will go away completely then.

As far as the lean condition is concerned I took a fog machine I had and hoked it up to the vacuum line from the brake booster and fogged out the intake system and found smoke coming out by the back of the throttle body, so when I replace the IAC valve I will be adding RTV gasket maker to the back of the throttle body gasket, this should seal it. I will also use RTV gasket maker on the IAC valve to make sure there are no leaks there either. This should eliminate all of my problems. I will post back with any updated I have.

do not use RTV, get a replacement gasket and use proper torque

Yup, if you use silicone and ever have to take it back off you'll be cussing yourself. I think the gasket is like $5? for the Toyota one from a dealership.

Thanks you guys! I will not use RTV, had no idea it was gonna be a bad idea, its all good we are all here to help and you guys just educated me, thank you! I wasnt able to get these gaskets at my local autozone so thats why I was just gonna use RTV. But instead ima get them here:

http://www.ebay.com/itm/Fuel-Injection-Thr...m9B&vxp=mtr
http://www.ebay.com/itm/Fuel-Injection-Thr...w0-&vxp=mtr

I'm going to replace both gaskets, might as well if I'm replacing the IAC valve with the other one I have.

K new gaskets came in today and will be installing these today, hopefully this will fix my issue and resolve me check engine light and have everything run normally and my gas mileage will go back up. I will keep everyone updated on this issue. I am wanting to turn this and eventually get around 200 to 250hp, pretty far fetched but before I do any more performance mods or even think about going turbo I want to make sure the motor is operating just fine and normal before adding performance parts to it and having it act all weird and possibly cause more issues. Just trying to get a good base to work with before adding on.

K added my new gasket, only did the throttle body to the intake manifold for now. That resolved my idle issue, however I cleared the code and it came back after about 80 miles of driving, I thought it was fixed but after 80 miles it came back lol. So I know I still got a performance issue and still some flucation when driving and below 2k rpm. so think its still the IAC or the position of the TPS sensor, I think it will need to be reset. so ima try that. I may also buy a new IAC.

Here's a thread for how 2 calibrate the TPS

http://www.6gc.net/forums/index.php?showto...TPS+calibration

gl

vavAlepVav. The OP has the ST engine and the tps calibration you posted is for 2.2 L motor. Is procedure the same for both. My ST is idling rough only on occasions so I am following this thread as well.

Thanks in advance.

ah,
Sorry about that.
The 1.8L uses slightly different feeler gauges to do the same operation.

the BGBonline at Celcia Tech is here. This has all the factory service manual procedures you need.
http://bgbonline.celicatech.com/94_6gmanual/94_6gmanual.htm

the specific page this is under is called Adjustments.
http://bgbonline.celicatech.com/94_6gmanua...adjustments.pdf

It's basically the same procedure using a .016", .024", and .035" feeler gauge instead.

Enjoy!

Meh, nevermind he already got to it.

This post has been edited by Box: Jun 12, 2016 - 1:50 PM

thanks I appreciate the prompt response.

I am having kind of a similar problem. I have a 95 Celica ST 1.8 and my car isn't passing 3,000 Rpms without going crazy shaking and holding back a full throttle.

It would shake real low to nearly turn off before running into this problem. Any ideas?