Problem After Installing Turbo XS SBE.. HELP!!!

[Aretimus]

Hello,

I installed my new Turbo XS SBE last night with the non fouler trick on the 2nd o2 sensor, and took it for a drive today. I noticed that towards the top of 3rd gear at wide open throttle something weird is happening. The engine seems to hesitate for a split second, it is a complete loss of power for a split second and then it resumes. I have not noticed this problem in any other gears other than 3rd so far. This has me pretty worried im not sure what the issue may be. No warning lights or check engine lights have come on yet as a result of this, I hope thats a good sign lol. I appreciate any help, tips or advice you can give me on this issue.

Thank you

 

[johns]

have a way to log fuel pressure by chance?

 

[AutoEuphoria]

What is a SBE?

 

[johns]

stealthback exhaust

 

[AutoEuphoria]

Ah, still no clue LOL. Is it from the midpipe area (2nd cat) back, or from the downpipe back or from the turbo back?

 

[johns]

turbo xs dp/rp combo
stock cbe

 

[MSMS3]

What other mods do you have on the car?

Who did the install - you or an independent shop?

Has the ECU been reset? Usually the battery is d/c'd anyway during the install and that would reset the ECU. If in doubt, remove the negative cable from the battery, wait a couple minutes and reconnect.

Typically it is necessary to remove the intercooler on top of the engine to access the turbo outlet studs to remove the old DP and install the new one. Because of this, it is possible that the installer may not have completely reseated and tightly clamped the piping/hoses to and from the intercooler, or you could have a vacuum line loose.

If things were running smoothly before the upgrade, there should be no reason for your problem.

BTW, even with the anti-fowler extender, I still get CEL's more often than not. They mysteriously stop and then come back. That goes with the territory. It may just be that your ECU is making short term adjustments to the increased flow capability on the exhaust side and this may pass.

But check those pipes/hoses going into and out of the intercooler and all your vaccuum lines. That may be your problem.

 

[johns]

but first let me know if you can log fuel pressure

 

[MSMS3]

but first let me know if you can log fuel pressure

Sorry, my question was directed to the original poster.

 

[johns]

i know it was. i don't think a vacuum leak causes stutter which is why i want the op to log fuel pressure before he does anything with vacuum lines.

 

[Aretimus]

Unfortunately i do not have a way to log fuel pressure. I did the install myself, everything is seated and tightned down. The ecu was reset when i did the install. I have been doing some research and it seems like it might be a torque limiting problem. The ecu limits the torque if you go too far outside the range it was in factory, and it does this by stopping the engine for a second untill the torque is back into specification. This does not throw a check engine light. I have a cobb sri, and a turbo xs bpv, along with the turbo xs dp/rp. I have a cobb ap on the way. The cobb ap is supposed to up the values on the torque limiting so it wont do it anymore. But unfortunately the maps call for a catted downpipe and i have a catless system now. So im not sure how im going to keep it from overboosting. Do you guys have any other ideas?

 

[johns]

yeah, get something to log fuel pressure

 

[MSMS3]

If you are sure all pipes and hoses are seated and tight and that no vacuum lines are loose, we can eliminate that. Did you have the aftermarket BPV before you installed the DP/RP, or did you put it on at the same time?

If it was previously installed and not causing any problem, then I agree with Johns that it's time to look at your fuel pressure readings. Can you borrow a Dash Hawk and data log? It is known that some of us have fuel pressure problems and don't really know it until a major upgrade creates a need for more fuel. Others (I guess I'm a lucky one) don't seem to have that problem, at least not yet.

If your TurboXS BPV went on at the same time as the DP/RP, you need to make sure it is connected properly and functioning properly. When you say it is a BPV, I'm assuming it a true BPV or a BOV running in pure recirc mode and that you do have the recirc line back into the intake. That can significantly alter the accuracy of the MAF reading. I'm not a voice of authority on the TurboXS BPV, tend to avoid pure BOV's and for the time am happy with a stock BPV that does not leak.

As far as ECU holding back torque, I could stand corrected, but I only see that happening in first and second gears. You should have true WOT in third gear and up, at least until the ECU sees you run into overboost.

Let's look at your BPV setup and your fuel pressure and see where this goes? I think Johns is right that you need to find a DH or other fuel pressure device that can measure and log our high pressure pump output.

 

[Aretimus]

The BPV was installed a few months earlier, and I havent had a problem with it. The BPV is a true 100 percent recirc. I have a Cobb Access Port on the way im not sure if it has the ability to read fuel pressure or not but i think it does. Ya 1st and 2nd gears are limited, so basically all the mods that are done to the car shouldnt make any drastic changes in 1st or 2nd. But 3rd is the first gear that we get full power and its also the gear with the highest torque since we get full power in this gear. Would make sense that a torque limiter would only show up in 3rd gear, since it doent happen untill high rpms and full throttle in 3rd. I am not sure on this but it does make a little sense. I cant get the hesitation to happen in any of the other gears. It is really wierd when it happens its like the engine stops producing all power for a split second then comes back. Still do not have any check engine lights. I know i will eventually throw one due to not having any cats on it.

 

[johns]

ap can log fuel pressure. make sure you do that. i bet your fuel pressure is dropping

 

[Aretimus]

Ok i will check that when i get the ap, what is the standard fuel pressure level?

 

[Moody]

could it be a spike in the boost levels?? and the ecu is triggered to back it down resulting in the limiting issue??

 

[johns]

400 at idle
1700 wide open throttle

 

[bykeryder4life]

i almost bet for sure that since the dp install your fuel pressure is dropping and thats the studdering you feel. Being cattless you most likely spike into the 17psi range anyways so your pump cant keep up. As far as what i read on the last page about a torque limiter and thats what the studder/hesitation is thats a bunch or crap the car doesnt have torque values that cannot be exceeded you will just be out of tune or blow the motor but it wont cut because you are making increased torque/HP those #'s mean nothing to the ecu.

 

[bykeryder4life]

. I have been doing some research and it seems like it might be a torque limiting problem. The ecu limits the torque if you go too far outside the range it was in factory, and it does this by stopping the engine for a second untill the torque is back into specification. This does not throw a check engine light. I have a cobb sri, and a turbo xs bpv, along with the turbo xs dp/rp. I have a cobb ap on the way. The cobb ap is supposed to up the values on the torque limiting so it wont do it anymore.

this is what i am referring to. theres no factory parameters you have exceeded that would make studdering to bring your cars new found HP and torque down to factory levels again. if this was the case then no matter what mods people do they would be at factory power levels and the car would cut and cut and "stop the motor" until HP /torque magically drops into specs... clearly not the case. I wanna know where you are reading this crap its very untrue.
The ap up's the values of boost in 1st and 2nd gear since they are limited from the factory to keep the tires hooked up but you wont even really notice it since the car spins through both of those gears even in stock configuration. I think you are mistaking this limit thats in only 1st and 2nd for being a limiter in all gears which is not so. the studdering you have is fuel cut get a new pump