sputtering at 7 lbs boost

[buddy3824]

i have 92 gsx and i was getting on a highway on ramp, its pretty congested so i got on it fairly hard, but when the car hit 7 lbs, it spits and sputters and just wont go at all, the turbo works fine up to 7 lbs, pulls good and everything, BOV working and sounds good, idk what the deal is, it acts like maybe it isnt getting enough fuel, i have a narrow band and a HKS VPC and GCC, but even if i turn the vpc up in response and/or gain or even tinker with the rpm band on the GCC, nothing is helping or hindering it, works good up to 7 lbs then acts like its not getting good gas or its not mixing right. i just need to know what to look at and what i can do to figure out what the prob is. i do have a small crack in the turbo mani and i fixin to get a better one, but the car is practicly stock, nothing big on it, fact turbo and manifold and wastegate. it does have the 255 walbro on it too. but the car was runnin fine for the past month that i had it. any help would be appreciated.

 

[snowborder714]

Boost leak test.

Oh, and get an AFPR to go with that 255lph.

 

[98gsxtuner]

You'll be running pig rich with that 255 and a stock FPR, I know i was and then i purchased a Fuellab FPR and now my car is running awsome,and it's most likely because of the crack in the manifold. Perform a BLT and see how much is coming from that crack.

 

[buddy3824]

im guessing the fbr is the factory wiring for the fuel pump and where do i find the bigger wiring kit at? i looked at ebay, but im not sure about that and how much time u think it take to rewire? and how do i before a boost leak test?

also, when is the narrowband give good readings? just at idle? or is it close at soeed? cuse ive been looking at it and speed and its reading more lean. but ive been told its useless at speed, but even at idle, sometimes its rich and sometimes it real lean, idk whats going on with it.

 

[buddy3824]

oo, fuel pressure regualtor, haha, but i still need to rewire it though right?

so i got some time at work today to look at the car some, and the manifold isnt leaking, the down pipe has a crack halfway around it :-o would this crack cause the car to lose pressure and sputter like i explained? or is there some fuel issues that still need to be resolved?

 

[snowborder714]

A narrowband gauge is not helpful at all, unless it's reading rich or lean all of the time. Then you might have a problem. But other than that, it's just a light show.

Yes, I would recommend rewiring your fuel pump. The eBay kit is fine (I have it) if you don't want to purchase the pieces separately or a kit from a vendor. Depending on how comfortable you are with wiring and working on the car it could take anywhere from a half hour to a few hours.

The downpipe crack shouldn't be causing sputtering.

Here's how to make a boost leak tester.
IC Pipe Tester

And just do a search on how to perform a boost leak and I'm sure you'll find info.

 

[Dsmj89]

Sounds like a boost leak. Do a boost leak test as everyone here has suggested. Also get a fpr for that 255, sounds like you might be running a bit rich from all that flow.

 

[buddy3824]

so i got to looking with a friend and it appears that the waste gate isnt moving, should i be able to manually open and close the waste gate? it is a factory one, and if so, that would probably be causing my problems correct?

also, if i need to replace, what should i replace it with? aftermarket? what kind a size does everyone suggest?

 

[kelvinb]

the wastegate opens and closes off vaccuum and boost, you wont be able to manually open and close it.

when you say 7lbs, are you referring to an aftermarket boost gauge you installed, or the factory boost gauge in the cluster? if its the cluster, than i reccomend you install a boost gauge as the cluster gauge 'assumes' boost, it is not a true boost gauge.

what makes you think its not getting enough fuel? i hooked a wideband up to my car when my fuel system consisted of a high pressure 255 pump and a stock regulator and i was getting 150 miles to a tank.

 

[buddy3824]

i think it might be getting too much fuel, and i do have an aftermarket gauge. ive got a fogger here at my shop that im gonna BLT for the turbo system like everyone else suggested.
but even when we reved the car, the waste gate didnt appear to be moving, but it wasnt making that much so it makes sense.
ive been getting about 22 mpg on highway so i know its getting good fuel. and something new has come up, im able to get it to go to a max of 10 psi, but what happens is if i try to give it more gas, then it sputters and hesitates, its like its limited to amount of pedal it can take.

 

[Defiant]

New plugs (NGK BPR6ES, .028") and wires.

 

[buddy3824]

blt turned up nothing, car is not running too rich, we tested fuel pressure and hooked up a wideband. car is still acting up seems to be doing it more often.

next step is like ^^^ said, im putting plugs on it today, looking into putting a GM coil pack on it for more spark and getting some 8mm solid core wires. does anyone know what kind of car has the right coil pack for same plug wire transfer on the dsm??

 

[Defiant]

Don't try to do repairs with non-stock replacements. Start just with the plugs and wires. The DSM coils can be used for welding, and really don't need upgrading until much, much further down the dyno curve.

 

[buddy3824]

the colder plugs fixed it for the most part it still hiccups every now and then, looking into getting maybe some accel wires and seeing if itn will fix all the way.