6G Celicas Forums

So the ongoing power loss/hesitation falling on its face is gone finally after hundreds in parts and lots of labor on my part. and the problem still was there and seemed to get worse but did not do it all the time.
Work done all new ignition parts fuel pum fuel filter sock pulled fuel tank and cleaned and pull injectors and had them tested by a friend still problem. The same friend who tested the injectors found the right problem, Now this is going to blow your mind what is was.
I had a non vented fuel cap on the car. As soon as he took the cap off the car pulled hard and had no issues. I looked up the type of gas cap that is needed and it says vented fuel cap. My friend is a bit more smarter at mechanic work. He said he noticed the fuel return line was pouring gas back into the tank.
When he pulled the cap it stopped. He said somthing about presure in the tank messing with the fuel pump and prsure.


I hope this is the problem but the car seems to be fine with the new cap on.
Anyone ever heard of a nonvented gas cap causeing issues when a vented cap is called for? Somthing so simple who would have thought.
And Import face off/ trackday is Sunday. I got new struts,motor mounts and inserts. Car has no wheel hop turns out my back mount was broke
Thus makig wheel hop. And man the mount inserts are the bomb I LOVE EM !!
I am running 16lbs boost and no issues yet. Car is stronger than ever

so you're saying you replaced your gas cap with another oem gas cap or what?

The fuel return line always pours fuel back into the tank. Thats what its there for.

That was not it I am stupid somtimes by believing people. I did find the problem i have a short by the throttle position sensor. i wiggle the wires and the car goes to kill. So I guess its doing it when I hit a bump and stuff. I am not sure If I need to get a new tps or the connector. I think it just the connector but I cant find it no where. Anyone got a 3sgte tps sensor and the connector thats goes to it. I cant find the connecotr no where. And is a gm style the same?

Might want to unplug it and take the car out for a drive without it to see if it makes a difference. Your tps could just be loose and out of calibration.
If for some reason you do need a new plug, drtweak sells them .

Thank lagos, I will try it with out it plugged in tommorow. The sensor is not loose not even the wires. nothing is loose but I can wiggle the wires and it affects the way the car runs like it wants to die. How to calibrate a tps?

look it up in the bgb. its far to involved to type out.

Yea found it a minute ago. It is detailed. i understand it but I gotta get that electronic tool thing to get it measured an set right.


Is the plug on the tps on a 3sgte the same as a gm one? i looked up my part for my celica at autozone and a gm plug came up

Yes I've heard of that.A non vented cap can cause the fuel system to "fight itself" to get fuel.Air displacement helps feed the pump.
Without the air relief,the pump struggles.Usualy,you can tell a vented cap is needed if you here a hiss when the cap is removed.

Yes i did hear a hiss when I opened the cap somtimes it had alot of built up pressure

Did what lagos said unplugged it and it runs fine. SO I ordered the plug not sure if the tps is bad but will see