6G Celicas Forums

Ok, heres my delima. Ive had my 1995 celica gt with the 3sgte for about 6 months now. Ive had an on going issue with boost not going past 7-8 and it goes into safe mode. Heres what I did to try and correct these issues.

-front mount intercooler 26x5.5x2.5
-aluminum 2mm thick mandrel bent intercooler piping
-header wrap on intercooler piping anywhere it may get hot (photos in my profile)
-rerouted intercooler piping away from exhaust as much as possible.
-ngk spark plugs BKR7E (gapped at .032)
-installed tvsv led monitor green/red
-disconnected stock gt exhaust and running 2.25 (after engine is open)
-xs power 3" dump pipe

I dont understand what exactly (other than knock) will cause the 3sgte to go into low boost mode. When its 80* outside and Im at a light it will go into safe mode. Once Im on the road moving for a minute or two it comes back to normal. Is this normal? Does anyone know what symptoms will cause the 3s to go into low boost mode? I know when its cold it goes into low boost mode, if it gets to hot will it do the same? Thanks

have you checked your base timing to make sure its at 10tdc with te and e1 bridged?

you should also do the multimeter tests on your afm. there is a temp sensor inside of the afm... normally it will put the car into low boost mode when its 40deg or colder outside, but if the sensor was bad, it could start doing it in warmer weather conditions.

Thats a good point. It makes sence the temp sensor is in the afm. I noticed when I got my swap the adjuster screw for the afm had been tampered with. Ill do some ohms tests via the shop manual. Thanks!

BTW: the timing is correct with E1 and TE1 shorted.

dont worry too much about the adjustment screw. it wouldnt really cause this problem. if you ever buy a wideband, i can tell you how to recalibrate that screw to the correct position.

but if your screw is out of wack, it would cause you idle to either be rough, or a little too low.

Ill have to keep my eyes open for another maf.

I got my water injection hooked up and I love it! It pulls much better and saw an additional .5-1.0 psi of boost! without adjusting the mbc. I also just installed a blitz sbc type R boost controller. Its great also.
I still am going into safe mode. I was convinced there was something wrong with my maf. But after the ride home today Im not so sure. Its about 87* outside. I drove home from work on the highway at about 75 mph for 15 minutes. About halfway home I turned the air conditioner on. about 8 minutes later the car went into safe mode. I turned the air off. The whole way home it stayed in safe mode. The engine temperature gauge stayed normal. When I got home the turbo timer ran for 2 1/2 minutes in the garage with the door open. When it shut off I lifted the hood. My coolant was boiling over and out the overflow jug! So I turned the car back on and the temp gauge was getting hot. I let it idle for 3 minutes with the heat on full blast.

One guess I have is the air intake setup I have is sucking air out of the engine compartment. I didnt see this as a major issue as Ive seen it done before on this sight. Also my intercooler is blocking the radiator. This cant help.
For now I want to try and move the air intake below the battery to suck cooler air and keep the maf away from the hot engine. Maybe the temp sensor is picking up the hot air and causing safe mode to be engaged. I want to double check that the cooling fans are kicking on when the car is at idle and when the a/c is on. I also want to hook up a toggle switch to the cooling fan switch so I can manually turn this on and off.
SORRY FOR THE LONG POST. IF ANYONE HAS MORE IDEAS, I WOULD GREATLY APPRICIATE IT! THANKS!

This post has been edited by toyotacrazy: May 30, 2007 - 5:24 PM

how much boost are you at?


your intake placement wont have anything to do with it. the ecu is programed to put the car into safe mode when its 40F or below. it doesn't lower boost in hotter weather.

have you checked your ecu for codes?

I have no codes and no MIL. Im at .8-1.0 bar

so that could be your problem ....

try this..
lower your boost as low as it goes and reset the ecu. then drive around boosting for the next few days and see if the problem goes away.

what boost should I run? nevermind, sorry

This post has been edited by toyotacrazy: May 30, 2007 - 10:15 PM

Does anybody know where I can find the information about safe mode in the toyota repair manual or TIS? I searched all over the TIS today and couldnt find anything about low boost mode or safe mode. I want to know exactly what conditions and all the conditions for low boost mode. Its 85* outside and I stay in low boost mode until my temp. warms up for a few minutes. I wonder if the ecu reads the coolant temp sensor and when the car reaches a certain temp it allows full boost. Maybe my temp sensor has an intermittant open circuit????? But my temp gauge is reading normal. It seems to be getting worse. I dont think this is hurting my engine by any means, I just want my tvsv monitor to be accurate. Thanks
-toyotacrazy

http://autoshop101.com/autoshop15.html

look through those articles. its all the stuff the bgb wont tell you.

ill try to give you a basic rundown of how tvsv works.

the ecu used the air intake sensor inside the afm as well as the coolant temp sensors and knock sensor to determine if its safe to allow full boost (tvsv green). when you start your car up in the morning, it will take a few moments for the light to go green. this is because the ecu knows the motor is not up to temp yet, and you should never boost on a cold motor. then after the engine has come up to temp, youll see the led turn to green when giving it some light throttle.

the ecu also looks at the air intake temp sensor inside the afm. if its 40deg or colder, it will keep the car in low boost mode (tvsv red), for the rest of the day. sometimes when you are stopped at a light, it might go back to green for a few seconds, because the engine bay temps are heating up the sensor, but soon it will go back to red and stay there.

the third sensor it looks at is the knock sensor. if you do a boosted run, and the ecu detects knock, it will put the car into low boost mode, and keep it there for quite some time. the ecu is smart enough to realize that if you just got knock from one boosted run, then chances are it will happen again. it could be anywhere from 1min or even 30min or longer that the car stays in low boost mode. during this time the ecu slowly advances timing back to where it thinks will work correctly without knock. if you turn the car off, wait a few min, and turn it back on, it should clear the low boost mode.

a lot of times people have an idea set in their head of what boost is ok for them to run, but what you have to remember is that ever car is different. you could have anything from low octane gas, bad intercooler, bad afm, bad fuel pump or problems with your fpr, causing you not to be able to run as much boost as you should. a good way to diagnose these issues is to reset your ecu, and lower your boost as much as possible. if you are still seeing the problem at 7psi, then chances are its a bad afm or maybe a bad coolant temp sensor causing you these problems. if the problem goes away, then you can start to slowly turn up the boost little by little to see whats going on. going to a dyno while you do this would help diagnose things even more.

good luck!

Thank you for the long rundown. I had an idea that it used these sensors, but never was said out right. I think I may have found my issue. I found a bad connection on the wire from the ecm to the green led. I wont know until it get hot outside again. If it still does it Im going to try a new coolant temp sensor. To try and eleminate an easy to replace/old sensor. I now need to check out the link you left me. Thanks again!
-toyotacrazy


This post has been edited by toyotacrazy: Jun 4, 2007 - 5:21 PM

i thought you worked for a toyota dealer? cant you just hook up the scanner and check out all the sensor readings?

My car has a 2nd generation 3sgte, which had OBD1. Its very limited what you can do. If it was a 3rd gen. 3sgte, 96+ then I could use the scan tool.

check your coil, a friends mr2 3sgte wouldn't boost right when his coil was bad!!