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Discussion Starter · #1 · (Edited)
hey guys,

before i put on my turbo, my car ran smoothly. i'm a ge-t

after i put on my turbo, my car is up and running, but my idle is very rough. it is also running on the rich side, and I made sure that everything is connected, twice. (vacuum, sensors, etc..)

when i step on the gas, the rpm will dip down to 400, and then when i take my foot off the gas, it will go back up to 800-1000. the idle starts from smooth (1000) and then jumps down to 600.

I have no idea why the car is doing that. can someone please help? :confused:

oh i'm also running open downpipe. no codes thrown at me as well.

also, everyone tells me there's a vacuum leak, but i really don't think so because I haven't touched any vacuums around the TB. besides a vacuum leak will just take my engine to stalling speed right away.


t61
stock injectors
stock fuel pump
wg @ 11 lbs
tial bov @ 9 lbs
2.5" piping
3" open downpipe
1.3mm HG
aem uego wb
aem f/ic (not installed)
ngk copper gapped at .065mm (0.026 inch)
 

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Your air/fuel ratio o2 sensor is broken. Check it out. Throwing a code?
 

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Discussion Starter · #3 ·
no it's not throwing a code at all. at least the CEL isn't on

how many stock o2 sensors do i need to hook up to at least let the car run smoothly? right now all 3 are connected (bank 1 sensor 1/2, bank 2 sensor 1).
 

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I doubt it's a vacuum leak as you said it's running rich.

What kit do you have? Do you have a black box? Is the car in closed loop when u're having this issue? What engine management?

I am of the opinion that it's just not breathing at all (TB is closed down all the way). As a test, can you try creating a small vacuum leak at the manifold and see if it doesn't run slightly better and lean out?
 

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Discussion Starter · #6 ·
thanks for the replies, but currently i do not have my F/IC installed. my friend think it's because of the open downpipe that is making my car running in a funny way.

the throttle was fine before i installed the turbo, and when i create a small vacuum leak, the car just stalls.
 

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I say tune it. if you step on the throtle and it drops, there are correct/compensation maps for that, open dump shouldnt affect your tune if anything.
 

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Discussion Starter · #8 · (Edited)
hmm, open downpipe shouldn't make a difference.
there's no vacuum leaks either
tps was working fine before turbo install
iac is working fine as well
throttle plate should be opening enough for idle
o2 sensors aren't junk (no codes thrown)

i really don't know what the hell is going on. If i go back to NA right now with my stock airbox, this problem would go away.

which means something is up with the MAF.

my MAF is connected to the AEM stainless steel intake tube, which is connected to my IC piping. When I was using the AEM intake as in intake, this problem would occur as hesitations in between gears and sometimes during gears.

edit: my spark plug gaps are gapped at 1.1mm, people are suggesting 0.635mm. i think i'm going to re-gap and see if it idles smoother, and on my way there, i'll check vacuum tubes for cracks or leaks.
 

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hey guys,

before i put on my turbo, my car ran smoothly. i'm a ge-t

after i put on my turbo, my car is up and running, but my idle is very rough. it is also running on the rich side, and I made sure that everything is connected, twice. (vacuum, sensors, etc..)

when i step on the gas, the rpm will dip down to 400, and then when i take my foot off the gas, it will go back up to 800-1000. the idle starts from smooth (1000) and then jumps down to 600.

I have no idea why the car is doing that. can someone please help? :confused:

oh i'm also running open downpipe. no codes thrown at me as well.

also, everyone tells me there's a vacuum leak, but i really don't think so because I haven't touched any vacuums around the TB. besides a vacuum leak will just take my engine to stalling speed right away.
Am I missing something here! How in the hell are any of you giving this guy advice on what's going on with his car without even knowing what his setup is? What his engine managment is or anything else that would give you a clue what is wrong. From what I read, he just said "I can't get the car to run right". That tells us nothing and any advice you've been given should be taken with a grain of salt. For the newbs who read this, if you have problems with your car, first list your setup to include what you use to tune the motor. No one can help you without knowing this info first!
 
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Am I missing something here! How in the hell are any of you giving this guy advice on what's going on with his car without even knowing what his setup is? What his engine managment is or anything else that would give you a clue what is wrong. From what I read, he just said "I can't get the car to run right". That tells us nothing and any advice you've been given should be taken with a grain of salt. For the newbs who read this, if you have problems with your car, first list your setup to include what you use to tune the motor. No one can help you without knowing this info first!
Exactly my previously posted thought!...
B1S1 and B2S1 are the only two sensors that will affect how the car runs. What is your fuel setup? What ems are you using? ...etc?
We need your setup in order to help you!
 

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Discussion Starter · #11 ·
sorry that i forgot to include this ( i thought i did), but i'm not running any tune at this moment. i'm using aem uego wb.

i'm going to install aem f/ic and see if it helps...
 

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sorry that i forgot to include this ( i thought i did), but i'm not running any tune at this moment. i'm using aem uego wb.

i'm going to install aem f/ic and see if it helps...
Dude, have you been reading the posts?? What is your entire setup? We need these things to help you.
 

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Discussion Starter · #13 ·
Dude, have you been reading the posts?? What is your entire setup? We need these things to help you.
t61
stock injectors
stock fuel pump
wg @ 11 lbs
tial bov @ 9 lbs
2.5" piping
3" open downpipe
1.3mm HG
aem uego wb
aem f/ic (not installed)
ngk copper gapped at .065mm (0.026 inch)

anything else?
 

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243 Posts
t61
stock injectors
stock fuel pump
wg @ 11 lbs
tial bov @ 9 lbs
2.5" piping
3" open downpipe
1.3mm HG
aem uego wb
aem f/ic (not installed)
ngk copper gapped at .065mm (0.026 inch)

anything else?
How are the stock injectors working? I can't imagine they are keeping up w/out some type of booster pump.

The AEM FIC sounds interesting and cheap if it works... but you are going to crack some rings (at least, guaranteed) @ 11psi with stock injectors the next time you step on it; they are not going to provide enough fuel for that much air.

Your idle should be perfect with the stock ecu and injectors, you must have removed an 02 sensor that manages the closed loop or have something backwards.

Your setup is not going to work without some bigger injectors unless you are running 5psi. Also, if you do change your injectors then your stock ecu won't manage the bigger ones correctly unless your FIC can compensate.

BTW you are throwing a code and should have a CE light on with only 3 of 4 02 sensors unless you wired the dead circuit to a remaining 02 to trick the ecu, or run a sim.

Good luck, just figure it out before you waste some serious cash.
 

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Discussion Starter · #15 ·
How are the stock injectors working? I can't imagine they are keeping up w/out some type of booster pump.

The AEM FIC sounds interesting and cheap if it works... but you are going to crack some rings (at least, guaranteed) @ 11psi with stock injectors the next time you step on it; they are not going to provide enough fuel for that much air.

Your idle should be perfect with the stock ecu and injectors, you must have removed an 02 sensor that manages the closed loop or have something backwards.

Your setup is not going to work without some bigger injectors unless you are running 5psi. Also, if you do change your injectors then your stock ecu won't manage the bigger ones correctly unless your FIC can compensate.

BTW you are throwing a code and should have a CE light on with only 3 of 4 02 sensors unless you wired the dead circuit to a remaining 02 to trick the ecu, or run a sim.

Good luck, just figure it out before you waste some serious cash.
Even with all the o2's plugged in, i'm still idling rich. Anyways i'm not throwing a light right now (3 out of 4 o2's).

When i let in a small vacuum leak on the intake side of the TB, it idles better, and the car no longer idles that rich.
If i disconnect the intake from the turbo, it idles better (with the turbo still hooked up to the exhaust, but intake is NA).
Is this a tune issue or a faulty sensor?
 

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Define rough...is your idle just too low or is it low and misfires are occuring. When you create a load by turning on your defroster did the idle smoothen out? Also when your idle is "rough" is the car at operating temperature?
 

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sounds like you ave a block in the piping, or the IC.


side note:

stock fuel system + boost = expensive

....by the way
 

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Discussion Starter · #18 · (Edited)
Define rough...is your idle just too low or is it low and misfires are occuring. When you create a load by turning on your defroster did the idle smoothen out? Also when your idle is "rough" is the car at operating temperature?
my rpm doesn't like to stay in one place, likes to "vibrate" a little (needle will hover around 700 but never stay at 700). no misfires, but idles pretty low (600-700). Never tried to put a load on the motor, but as the car climbs towards operating temperature, it gets worse (idles to 500 and sometimes at 400). it sounds like an american muscle almost... when i give it more gas, the rpm does not go up, and when i let go of the gas, the rpm jumps up and then comes back down again.

and i know boost w/ stock fuel system is expensive...but right now i'm just trying to get it idle smoothly.

the small vacuum leak I intentionally created was after the IC and before the MAF, and it made the car idle higher and smoother, even when operational temp. is reached.
 

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Hymmm check the piping before and after the intercooler. Like somguy2u said there could be something blocking it. You might not have removed tape covering the intercooler end tanks. But if you intentionally created a vacuum leak after the intercooler and idle improved then look at the components before the intentionally leak.
 

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Discussion Starter · #20 · (Edited)
update:

got a boost gauge planted on the intake manifold, and the vacuum reads 6.8-7.0 absolute PSI. 7.0 - 14.7 = 7.7 vacuum. A healthy vacuum is 17-22 PSI....so I do have a leak on the intake manifold. The leak i intentionally created on the intake side creates more air to compensate for the leak, so i guess that's why I idled better.

Since i'm 100% positive that i have no vacuum lines hanging, is it possible that a gasket is bad? i recently replaced all the gaskets with new ones.

Just out of curiosity, how much vacuum do you pull? please include your engine compression ratio.
 
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