Celica Forums General Discussion Exterior engine problems

I have a 2000 celica gt i got a few months back. I installed my exhaust and a few days after i put in my cold air intake the check engine light came on, saying its running lean. I got a air/fuel gauge to find out whats going on and its saying i'm running fine unless i put the pedal that last quarter of an inch to the floor, then it runs at the bottom red bar on the lean side. If i let the gas go a bit, it will be fine and i can run it straight to the redline, does anyone know why this would be happening? Could it be the fuel injectors or something along those lines?

Did it happen right after you installed the CAI? it is possible you got something in your MAF (Mass airflow Sensor). also, how long has it been since the install exactly? the ECU could be, well, "confused" if you did both installs at the same time.

MAF doesn't determine rich/lean conditions in the motor, the o2 sensor does that.

Try disconnecting your battery, let the backup battery on the ECU discharge by letting it sit for a couple minutes. after a minute or two, reconnect your battery, start the car. let it idle until it warms up, then, turn your AC on full blast for a minute.

turn off the AC, rev the motor to about 3 grand, and keep it there for about 30 sec. and repeat this same step with the ac on again. once done, take the car for a spin, try engaging the lift and such. your problem should go away.

After all these mods, you have to reset the ECU, and let it re-learn how everything works with your new mods, since it's now breathing better and the exhaust is flowing better. resetting the ECU will allow it to figure out how to compensate for the added flow. it may seem like overkill, but all these steps are helpful to do it properly. the reason for the AC is so the ECU can figure out how to react to the loading of the AC pulley when your Air is on.

You also may want to double check your hoses on your vacum fittings and intake. a vaccum leak can cause a lean condition, as can a mis-routed hose. refer to the vacum schematic under the hood to double check everything.

Listen to rave669 sounds like he knows his sh*t.

do what rave said

i think it might have been a hose leak, not sure yet if its fixed or not, its taking a while for my car to recalibrate, which i've done 3 times before this, the hoses didn't dawn on me til when rave said it and my other friend thought they might be loose when he heard something from my car. I also cleaned off a few sensors and stripped of my rear logos while i was waiting for the car to cool down, thanks a lot for the help, i'll let everyone know how it turns out.

nope, didn't work, now its just pissing me off, but oh well, we'll see in a few months whe i take it to the shop or someone comes up with another idea, thanks for the help.

fuel pump???? im guessing now

Nah, if it was a fuel pump, it'd be more than a check engine, the car would run like crap if it was a major fuel system component.

Well, if all your hoses are routed correctly, and none of them are leaking, and you have reset the ECU like I said, and you still get a CEL, here's what you should do next.

1) pull the ECU codes, they will tell you exactly what the CEL is coming on for.

2) there is a possibility that one of the hoses is defective. pull off a hose, put your thumb over one end, and blow into the other. if there are pinholes or cracks in the hose, you will know, since the air will leak out in a spot other than by your thumb. if a hose is leaking, replace it.

3) did you remove the butterfly vaccum solenoid? (the vaccum bit that controls the intake butterfly) If you did, just reinstall it, even if there is no butterfly in the intake, it may correct your CEL if you reinstall it. I've also heard other people have had this issue when they install an intake, it's usually either a hose routing error, or they needed to put the butterfly back on.

BTW, I know a lot of intakes come with a little plastic nipple to block off one of the vaccum ports since the nwe intake doesn't use it. if that's the case, did you check that too? it could be another source for a vaccum leak. also, double check all your plugs on the wiring harness that you may have disconnected when installing the intake, maybe one of them is loose, and it's causing the CEL to come on.

If it were my car, I'd pull the ECU error codes, and do a complete vaccum system check. At this point, I'm pretty sure it's a vaccum leak now from what I've been hearing so far.

is the car running any differently, I.E. rougher idle, hesitation or anything like that? if it's only the CEL, I'd say that it has to do with how the hoses are routed, or possibly a butterfly removal (but the butterfly only applies to the GTS)

Don't sweat man, we'll help you figure out the problem regardless of what's wrong.

BTW, have you tried e-mailing Injen about your problem? tell them that your check engine light is coming on, what type of intake and car you have (incluting thansmission type and model year) and they should help you fix the problem. also be sure to tell them what you have already done to try and correct the problem. they may have an updated install guide for your application.


the e-mail address is tech@injen.com

any other time the gas isn't pressed to the floor the car runs fine, and the code coming up is a lean code, thats the first thing i checked out, and thats why i got the gauge, to tell me whats going on. It only runs lean when i open the throttle all the way up, it doesn't matter what rpm i'm at. i can run it to the red line if i don't open up the throttle that last little bit and it runs fine.

Hmm... That is odd. I'm still thinking it's vaccum related though.

it's staring to sound like you're getting a pressure drop when the TB is at wide-open, which would be caused by either a vaccum leak, a loose silicone coupler on the intake that is letting air leak through, or possibly, one of your hoses is colapsing on itself under hard vaccum, which is restricting it.

It may not be a leak after all, rather, it may be a blockage that is turning on your CEL.

get another hose, one with thicker walls (such as a rubber vaccum hose, rather than silicone) try swapping the new hose in place of each silicone hose that you replaced, one at a time. see if your problem goes away when you find one that's defective.

I once had a car that had a CEL coming on constantly, I eventualy figured out that one of my new silicone hoses was collapsing under vacum, so I replaced it with a thick-walled Akimoto silicone hose, and the problem went away after I reset the ECU.

See, when you floor the pedal, the system is at full vacum. If one of those hoses has a thin spot in one of its walls, it will collapse at the thin spot, and pinch off the flow, which will restrict vacum and could possibly result in a lean condition. so that's what may be happening in your case, since it's only affected at WOT.

If that's not what's causing the problem, you should contact Injen for some help, since I'm starting to run out of ideas... it'd be a different story alltogether if I could actually physically work on the car, but without a hands-on, I can only offer suggestions. A quality mechanic can do a complete check on the vaccum system and find the problem right away.

Thanks a lot, i'll check the hoses tommorow if i get a chance, and i emailed injen too with the problem, see if they've heard of it before, i'm in the middle of painting my interior blue so i'm going out to pick up some more paint tommorow, i'll pick up a hose while i'm at it. Thanks.