hey guys, long time member here but I haven't posted in years...

here are the details:

turbonetics single turbo kit
utec by Jeremy at what used to be performance factory.
03 6 speed has been turboed for around 3 years, running great on around 10lbs, stock internals.
60k miles, half of them boosted.

anyway here is the problem... when accelerating under any sort of pedal, right around when the turbo kicks in the car starts hesitating and bucking, almost like it's misfiring. so I first check my spark plugs, they look okay but I replace them anyway with what was in there (ngk r one step colder) and go for a test ride, same problem. brought the gap down to .034 and still not good. Boost gauge shows full boost...I hear the turbo spool normal, wastegate opens fine.

so I get busy tightening all of the clamps on the pipes making sure there are no leaks...

what else could cause this? coil packs? boost leak? bad maf?

Car drives perfectly fine when it's not in boost... but when boost starts... it hesitates and jerks... there is a serious lack of power too, like the turbo just isn't there. it's kind of inconsistent though... Sometimes I feel a small kick in power here and there throughout the power band... usually when not in wot, just partial throttle in boost... but then it starts hesitating again.

help!

 

Hey bud. Sounds like a couple things to me. Could be a boost leak somewhere. The best way to check this is buy a boost leak tester from eBay. They are around 30 bucks. Awesome investment.

Second thing could be a bad turbo. When mine started to go out It did all sorts of weird things.

Third could be something wrong with your fuel system. Maybe it's not getting enough gas when it needs. Maybe a retune would help. Maybe upgrade to Osiris.

I have a turboneics kit myself if I can call it that. I rebuilt my tnetics turbo with all garret innards. I'm having custom intercooler piping to match the momentum and be 3 inches all around. Having my down pipes redone to 3 inches. Lol. All to get 550 once I build.

 

having similar problem..going to check the gaps and tbolts

 

Some data logging would be helpful in diagnosing the problem

 

mine was due to the plug gaps

 

Same issue hear with my TT setup I going to change my camshaft sensors,hopefully it works..

 

You guys like to just throw random parts at your cars in hopes of fixing the problem?

How about actually doing some data logging to try and narrow down your problem area? For starters what is your AFR?

 

im guessing fuel issue and definitely data logging will show that
perhaps spark gap too large but usually that shows up in higher rpms etc

 

recent update:

I think the car fixed itself. i've noticed that the hesitation seems to happen more often when the gas tank is under half way.

Riding to the gas station one morning before work...i got on it and it was bucking and hesitating again...i pull in, fill up...drive off...and test it out, drove perfect, power was there, no hesitation at all.

does this sound like a weak or failing fuel pump? I've had luck lately to where even if it gets low it doesn't buck or hesitate too bad....but it def runs more smooth on a full tank.

 

def sounds like a fuel pressure problem then

 

Sounds like the FPR is taking a dump. What kind of fuel setup do you have? As mentioned above, use the datalog feature and do some brief acceleration. If it leans out definitely stop trying to recreate the situation. That's how engines go bye bye.

 

it's the stock FPR, are those known for taking a dump?

Also forgive my ignorance...but it's been years since i messed with this set up at all... how do i datalog? I don't even have a wideband

i read somewhere that walbro fuel pumps really only have a lifespan of around 4 years at most, i'm wondering if this is true?

 

It seems to be a weak spot once you go FI. I can't speak for NA owners since i purchased mine with a TT kit installed.
In regards to datalogging You have to link your laptop using hyper terminal or something. Not too sure about the walbro info. I went from DW300 to walbro416 and now in the works for something fancy from CJM.

 

Bumping an old post...

Car still having issues, and its very inconsistent.

Again, runs fine right up until the turbo kicks in and starts building positive pressure...then it doesnt pull hard at all, and hesitates/bucks pretty bad. enough to make merging on the highway difficult at times.

Even after filling the tank up, it can run bad....but it's really hard to pin point when it runs bad. I took apart all of the intercooler piping and reclamped it to assure proper fit. This is really starting to drive me crazy...

How would i datalog? What should my next step be? I really need some guidance here guys!

 

are you running a boost referenced FPR ?
if not that could be part of the fueling problem