car sputter at 100% throttle

[kamikazee47]

i got my ecu tuned for 740cc and z32maf my problem is the car would sputter when i give it 100% throttle and won't rev pass 3k or so. but when giving it little throttle it would rev pretty smoothly

my SAFC settings are set at 0% HI/LO, th points are 14% 45% my in and out are 1in1out sensor is 1-1

but when i set the hi map to -26% it would rev okay at 100%throttle, even though it would rev ok just free revving it, but when i drove it, it would sputter underboost,

[ghx407]

IIRC, your SAFC in/out settings should be something like 5/5 or 6/6. Set the Hi Thr map back to 0% and give it a shot.

[kamikazee47]

5in5out arent those setting for stock ecu with stock maf? i have a tune ecu for z32 maf with a z32 maf.

[TheOne]

it should actually be 2/2, as Z32 MAF on safc is 2.

[eazye2000]

it should actually be 2/2, as Z32 MAF on safc is 2.

My ECU is tuned for a Z32 MAF and 2/2 works fine. No need to 'trick' the ECU if it's already tuned for it. As stated above, the Z32 MAF is '2' on the SAFC II. Now, if you have an SAFC I or whatever with the knobs, I have no idea. But it sounds like you have the number two.

Food for thought. Enjoy..

*Edit* Also, do you have a wideband? I know your car will sputter, and detonate if you run it lean. Maybe adding the fuel helps because of this 'lean' condition. Check it out, get back with us.

[kamikazee47]

yeah i've tried 2in2out my car sputter at 100% around 2.5kish and it doesnt rev pass that while driving, but giving it bout 12%throttle or so it would drive pretty smooth

[480sx]

If you have an ecu tune you shouldnt need to run any adjustments with your safc2. I guess you dont have a WBO2 to check this though.

It kinda sounds like you have a boost leak though.. Make a boost leak detector and check your system for leaks.

If you dont have any, contact your tuner and tell him whats going on.

[frsh13]

I dont think it is your SAFC settings as you have a tuned ECU. Could it be a bad fuel injector maybe?
Modified by frsh13 at 12:16 PM 12/26/2007

[kamikazee47]

how would i test it

[kamikazee47]

i don't think i have a boost leak, b/c it would boost fine under light throttle

[480sx]

Yea, that makes no difference. The only time you would notice a small boost leak is under WOT, or close to it. You can do a vacuum test first to see if you get anything. After that, look at the stickies on how to make a boost leak detector. I just used a 3 inch piece of IC piping, taped up on one end witha bunch of duct tape. I punched a hole in the tape, then attached it to the intake side of the turbo. Then i used an air chuck to pressurize the system. You will hear air coming out of somewhere, its best done with two people. One to keep the system pressurized, one to listen for leaks along the IC pipes and intake manifold.

If it was an injector you would most likely have problems at idle, and everywhere else. Since you only have problems at WOT then it means is probably a boost leak, or tuning issue. If you want to check your injectors, get your car at a stable idle. Then take of each injector plug one by one. Your looking for an injector thats stuck open. If theres an injector thats stuck open, pulling off the plug on the stuck injector will do nothing to the idle quality.

[Florida240sx]

Wait you have a tuned ecu and your takign away 26% fuel???? Your probably lean as h3ll and about to blow your motor

[kamikazee47]

thats the only way i can drive it without the car sputtering

when the correction was set 0% across lo/hi it would sputter at WOT and would not rev past 2.5kish

could it be that i have a bad maf?

[coolbone28]

Where did you get your tune from?What is your timing set at?If your mafs was bad you probably wouldnt be able to rev past 3k at all. Its possible, so you should check it just to eliminate it. Also, i would completely disconnect the SAFC. You are adding way too many variables to diagnose a "sputter".

[480sx]

If your maf was bad you wouldnt be able to rev at all. Its either a boost leak or a bad(rich) tune. You realllyy shouldnt mess with the SAFC without a wideband man, your gona blow your engine.

[kamikazee47]

so might be a bad tune? should i just leave the safc to 0% across b/c this is my DD. it was tuned by EFI Specialist, injector are good tested them out and no sign of boost leak, i taped up the inlet of the intake and poked a hole in the tape then shot it with an air chuck didn't hear or feel any air leaking out. is there a way to tell how big your injectors are b/c they might of send me the wrong size

[eazye2000]

OH man! EFI Specialist/Jason is giving himself a bad name!

Not really. I have his tune, and I preached it for the longest time. But now, this is the 2nd time it's come up as a "Possible 'Bad' ECU Tune".Keep in touch with him. He's a really good guy. Just narrow everything down before you start blaming the ECU.

Just my $.02

[kamikazee47]

i don't know what else to check.

[coolbone28]

Well where did you get your injectors at?

what is your timing set at?

You need to do have an actual sealed boost leak tester so you can actually pressurize your whole system. poking a hole in some tape is not going to cut it lol man...whole new term to ghetto rig.

Did you ever check your MAFS or mafs wiring? There are so many possibilities to go over before you start complaining of a bad tune. That should be your last result.

Was your car boosted at all before this or is this your initial setup with the inj, mafs, and ecu?

[kamikazee47]

yeah it was boosted with 370cc with stock maf and stock ecu

[240sxvaj]

it should actually be 2/2, as Z32 MAF on safc is 2.

sorry to cut in out of nowhere but mines at 6in6out is that okay for my stock maf s13 ka24de-t25? By the way my AFC NEO should be the same as AFCII i believe?

[kamikazee47]

try 5in5out that is what i had with stock maf and stock ecu

[240sxvaj]

i'll try that out. thanks

[frsh13]

not sure if you figured this out yet but when you do please post up what it was... I have a similar problem going on with my car right now (When I get the time il make a long thread about it)

[kamikazee47]

for right now this is what i did until my wideband arrive, i set my lo map to 0% across and hi map 24% across and set my throttle point from 25%-45% it idles at 1k and drive pretty smooth when i keep the throttle under 25%. i still havent figure out why i can't run WOT.

[C-Kwik]

Sounds like your spark is blowiing out. You may need to reduce the gap or get an ignition amplifier.

[kamikazee47]

what type of plug should i get i have ngk bkr7e right now at .034 gap, and how much should i gap it to

[C-Kwik]

The gap should be set as large as possible without getting blowout. But generally, the more air and fuel you stuff into the cylinder, the more resistance there is across the plug gap.

The type of plug is not completely relevant. Heat range is determined based on application, as it should be cold enough not to be a source of detonation, but hot enough to burn off deposits on the electrodes.

However, you might try a platinum or iridium plug as the electrodes are narrower reducing the quenching effect and resistance across the plug gap. You should only need a single platinum or single iridium plug if you decide to go this route as you don't have a direct ignition set-up. Though, you may still need to reduce the gap, it may not need to be reduced as much.

It's been a long time since I had the KA-T, but IIRC, I was down to about 0.30 inches and running only 6.5 psi of boost.

[ilovecoupes]

maybe check your TPS

[240sxvaj]

try 5in5out that is what i had with stock maf and stock ecu

i tried that out today and car idle like crap on cold start up such as 1000rpm. so i put it back to 6in6out and smooth high idle on cold start and drops to 900rpm when warmed up. SO does this mean i am Okay with 6in6 out or it doesnt matter as long as my car runs good.??