Thread: AFR goes up and down 10-14 after turbo install. Need help tune going to sht

I just finished my turbo install and my AFR is going out of wack. It starts at 10 and climbs to 14 and lingers for 3-4 seconds then slowly drops back down to 10 and back up.

At first I thought it was because I lost a O-ring at the 4th cylinder injector hole but I found it and removed it and replaced my orings and it's still acting funny.

What esle could it be?

I'm using purple 577? srt4 injectors with a 255walbro. SAFC and my zt-2 is giving me weird numbers.

from 10 t0 14 it takes around 20second and from 14 to 10 it takes 1 second.

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Have you tried pulling fuel under low throttle settings? Could be the ecu freaking out over the bigger injectors and being unable to keep afr's at stoich.

Where is your wideband.
Is it a Zeitronix wideband
Is your turbo new (leaking turbo will foul up your wideband reading with oil)

Explain those readings vs RPM and Throttle

Originally Posted by MisterNuts

Have you tried pulling fuel under low throttle settings? Could be the ecu freaking out over the bigger injectors and being unable to keep afr's at stoich.

That does make a little sense, i'll try to pull some tomorrow.

Originally Posted by Joe@2J-Racing

Where is your wideband.
Is it a Zeitronix wideband
Is your turbo new (leaking turbo will foul up your wideband reading with oil)

Explain those readings vs RPM and Throttle

My wideband is at the end of the turbo downpipe near the flange.
Zt-2 wideband
Turbo is used but how will i know if it is leaking oil? Bust open one of my intercooler pipe and check for oi l?

It's still on ramps atm because I dont know if it's exactly safe to drive.

Wait.. what?! HAHA.. its under no load.

Even if it isnt under any load, shouldn't the numbers be still on idle?

Also my oil pressure gauge isnt reading so I don't want to drive it just yet.

Originally Posted by frozenbarb

Even if it isnt under any load, shouldn't the numbers be still on idle?

Yes, they should hover right around 14.7... I think Joe's drunk again

danny, drive the car.

Purple 577cc srt4 injectors...? The 577's are black and blue. Not sure what injectors you're using.

Oh, finally did the research since the seller never told me the CC. They are stage0 527CC injectors.

Anywho I'm going to drive the car tomorrow and find out how to pull fuel from the low throttle.

you're tuning via safc? if i'm not mistaken, i'm pretty sure the ecu can only handle a +25% increase in injector size before it flips the fuck out and runs like junk at low rpms and idle. if that is 100% true, then your injectors may be too large for the ecu to handle at idle via an safc. but that's just my guess.

also you won't be able to tune below 3k rpms (without unplugging your primary o2, which may or may not make your car run like shit). doing this pretty much puts the car in open loop all the time, so you'd be able to use the safc to tune idle, but even then it would still idle like shit. you need something much more efficient to tune with such as osiris or jwt reflash.

but like i said, that's just my guess, i could be way wrong.

The split second ftc1 still up for grabs lol Just saying

Your AFRs are doing what they are supposed to, under no load. Dips, corrects, dips, corrects.

You need to simulate load, either a dyno or road tune. With no tune, those injectors and FP, you will run pig rich.. It wont detonate. You'll be scaling back as much as 30%. Also, if your MAF is non-oem, it will cause some pretty poor readings.

^ yeaah I know but I don't want to hack up ecu even more and pay 500 for a tune at VTR..

Originally Posted by Joe@2J-Racing

Your AFRs are doing what they are supposed to, under no load. Dips, corrects, dips, corrects.

You need to simulate load, either a dyno or road tune. With no tune, those injectors and FP, you will run pig rich.. It wont detonate. You'll be scaling back as much as 30%. Also, if your MAF is non-oem, it will cause some pretty poor readings.

I see, so I'm guessing it might be normal. I'll go take the car out for a drive maybe the ecu will fix itself.. I'll be getting a street une on thuursday for high throttle.
But if my ecu is freaking out on low throttle and I can't tune low throttle how do I correct the ecu?
Get smaller injectors?
Pretty sure my maf is oem too.

You can tune low throttle, in fact you have to for larger injectors. Give it a try and see if it helps. AFR's should not be fluctuating that much IMO, but I've never dealt first hand with injectors that large.

On tip in, under no load, it doesnt matter so much. His ECU isnt scaled for the injectors so its doing what its supposed to

Originally Posted by frozenbarb

^ yeaah I know but I don't want to hack up ecu even more and pay 500 for a tune at VTR..

:smh: BRING THE LUBE (NYers will know what i mean(some))

but your in NY you got a lot of sentras around there... let them help yea, im sure you can also find some cheaper spots for a 2-3 hr dyno/safc tune.

The POS is still raising and dipping but i'm not sure if it does it when i'm driving at 2k rpm i'll test again in a few.
I did all the relearns and it fixed something but I think i hear my throttle plate rattling. I'll upload the vid in a couple hour.

I still have not tried messing with the low throttle fuel yet. I have to meet up with un33dit for a street tune.
Do you guys think it's safe to drive for an hour or should I get it fixed first?


On a side note, i was so excited my oil gauge was working i reversed off the ramps and forgot about the bucket of oil under my car.. and BOOM oil everywhere

Bump, it's still dipping and sht even when driving and underload.. do you guys think it's safe to turtle a hour awaY?