2G Boost cutout/sputter?

[Vistagecko]

Just installed an evo 3 big 16g on my 97 Gst. Stock fuel pump/injectors. 3 in turbo back exhaust. Stock sidemount with hard piping.

The car will start to build boost and begin pulling, but at about 4500-5000 it starts to sputter/cutout. It will jerk stop, start, stop and jerk the car and you can hear the tubo fluttering almost. If I let off the throttle it stops and is perfect outside of boost.

Is it a boost leak? Iv also read that spark plugs could be the problem...any help is appreciated.

 

[jmye86]

Sounds like fuel cut! With a 16g you will need to upgrade your fuel system the stock system can not supply enough for the 16g.

 

[gtbread77]

+1^^^ for me. FUEL CUT!!! try to just run wastegate spring boost, should be ten lbs. maybe you won't detonate your motor before you get some fuel upgrades or downgrade your turbP next time use the search forums option, there are hundreds of post with what your looking for already discussed.

 

[dsm03]

Just installed an evo 3 big 16g on my 97 Gst. Stock fuel pump/injectors. 3 in turbo back exhaust. Stock sidemount with hard piping.

The car will start to build boost and begin pulling, but at about 4500-5000 it starts to sputter/cutout. It will jerk stop, start, stop and jerk the car and you can hear the tubo fluttering almost. If I let off the throttle it stops and is perfect outside of boost.

Is it a boost leak? Iv also read that spark plugs could be the problem...any help is appreciated.

I have the exact same mods as you my friend, except upgraded fuel pump 190 rewired, at first I thought it was the infamous boost creep and though longer on it, by 4500rpms and on sputtering and cutting out.. I have no doubt its fuel cut. Turned down my boost from 15psi right down to 8-10. Doesn't do it so much anymore til I get close to redline. So, what am I doing leaving it set that way and not getting on it til I get my injectors installed and eprom.

 

[Vistagecko]

I searched but I couldnt find anyone with a similar problem with a similar setup to mine.

^^^
And thank you, I planned on going to 550-650 injectors. Everyone suggests link, but would SAFC 2 be sufficient for those injectors?

 

[jmye86]

If I remember correctly the Safc2 would be sufficent for those injectors but any larger you will need link.

In my opinion go with link. You have so much more capabilities with link and you will be limited to what you can do with safc.

Sent from my iPhone.

 

[GRAVEDIGGER]

You'll be okay with up to 650's with a SAFC.

 

[XiKeiyaZI]

Ahem. The fuel system will support the 16g, but not to it's immeasurable potential. You can hit 'fuel cut' on a stock turbo, which is a no brainer that you can hit it a bit easier on a 16g. The real question here is : How much boost are you ATTEMPTING to run on that stock fuel system?

Turn the boost down and go from there. 16PSI on one turbo is not equivalent to 16PSI on a better turbo. Aside from the possibility of fuel cut, you could have bad plugs, plug wires, or be blowing out spark. To solidify this, my friend just picked up my old GST. When I owned it, I was able to run 17PSI on a 14B with absolutely no issues. He is now only able to run 14PSI before hitting a stuttering issue at 5500RPM. With no leaks and no other issues and running in better condition, it points to bad ignition at higher RPM's.

When is the last time you performed a basic tune-up?

 

[LiquidX]

On a stock 2g fuel map, run wastegate pressure on a true MHI 16g so you stay out of 100% IDC. For any higher than that you want/need a new fuel system (pump, injectors, AFPR [recommended], and a way to tune).

1g fuel maps can run a little higher as the 14b is closer to the 16g but it's still a jump away.

 

[target12]

SAFC will do the job, but link is so much better for not much more money. Save youself for the long run and go with link.

 

[Vistagecko]

I took the plugs out blasted the tips, checked the resistance and put them back in, probably 2 months ago, but just recently started the car since then on friday.

So if Im understanding this correctly, 650cc injectors, a wally 255, AFPR, and a SAFC should do the trick?

Only reason Im straying away from Link is because Im probably getting rid of the car sometime in the next year and really just wanna have some fun with it till then. And my buddy is selling me his SAFC for 110.

 

[scott90gsx420]

Ok well idk but every time i felt fuel cut. it felt like driving into a cement wall for a second or so. As others have said boost leak check. run straight to the waste gate untill you get added fuel. As for injectors i run the evo 8 560s and a 255 and afpr set to 45base pressure. i havent logged the car since i put my b16g back on but before i was running the evo316g at 24 with same mods and raised fuel pressure a bit and ive never had any problems with either set up. So i personally would go with the 560s as they will give you less timing advance then the 660s and with the 255 and afpr you can make them flow up to 650s with a large raise in fuel pressure if you feel they arent enough.

 

[HooKnBooK]

It is fuel cut. The stock fuel system can't even support a 14b on high boost.

 

[surefire89]

Im running a BIG T28 on my 99 GSX 7 Bolt and have a Walbro 255 and Aeromotive fuel pressure regulator. I set my manual boost controller to 12.5 psi of boost and im still getting fuel cut with the stock injectors. What is everyone running for fuel pressure?

So I dont think its fuel cutout im getting anymore but im really confused on what it could be. I get into boost at wide open throttle and around 5000 rpms i get hesitation in the engine slightly and if I keep going to 7000 I get full cutout. Any ideas?

 

[ssicb]

don
t mess around and get link straight up. used can be had for around $500

 

[merjay1979]

I have a 98 gst all stock except for the greddy bov.
My car is sputtering as i gain boost at 4200 rpms mainly in 3,4,5 gear.
But if i acclorate slow or mildly i dont have this problem. The guy i bought the car from removed the cat and installed bosch double platuim plugs and 8mm accel wires.

 

[hypergenesis]

I have a 98 gst all stock except for the greddy bov.
My car is sputtering as i gain boost at 4200 rpms mainly in 3,4,5 gear.
But if i acclorate slow or mildly i dont have this problem. The guy i bought the car from removed the cat and installed bosch double platuim plugs and 8mm accel wires.

Go buy the NGK Copper tip spark plugs bp6 or bp7 I believe. For some reason our cars hate anything other than copper

Im running a BIG T28 on my 99 GSX 7 Bolt and have a Walbro 255 and Aeromotive fuel pressure regulator. I set my manual boost controller to 12.5 psi of boost and im still getting fuel cut with the stock injectors. What is everyone running for fuel pressure?

So I dont think its fuel cutout im getting anymore but im really confused on what it could be. I get into boost at wide open throttle and around 5000 rpms i get hesitation in the engine slightly and if I keep going to 7000 I get full cutout. Any ideas?

Well if you have stock injectors thats probably why...Just because you upgraded your fuel pump and now the pump can push the gas to the engine doesn't mean that your injectors can pump that gas into the engine as fast as the pump is delivering it.