Boost Jumping Back And Forth After CS SRI Install

[Blitzkrieg]

I finally got a chance to install my Corksport sri a couple days ago and for the most part its amazing, but im getting this weird boost spiking in 5th and 6th gear. This will only happen in 5th and 6th gear every other gear spikes then settles in at around 16.5 psi and holds. pretty much whats happening is in 5th and 6th under wot the boost will jump back and forth between 19 and 15psi until i let off the gas. so if you were to look at the boost guage when this happens the needle will sweep 15-19-15-19-15-19-15-19-15-19 you can even hear the suction sound of the intake change with the spikes. I checked all my connections and even reset the ecu again, i even swapped out my guage with my freinds just in case and the same thing happens. Does anyone know what is causing this.

MY car is a 2009 MS3 with 7200k and my only mod at this moment is the CS SRI.

 

[MSMS3]

It may take a hundred miles or so of driving for your ECU to "learn" the changes in the intake. It's probably doing some electronic "hunting" and may be pulling boost back trying to sample and adjust. This may smooth out.

Where (rpm range) would those 19 lb. spikes be happening, perhaps where it is just coming up on boost between 2500 and 3000 rpm, or higher up at say 3500 rpm?

 

[Blitzkrieg]

i did a few complete 5th gear pulls on the highway from 2500k to 6200k and it does through out the entire rpm spread. if im rolling on the highway in 5th at around 3000rpm and i punch it ill be at 19psi at around 3500 give or take then it drops down to 15 then back up to 19 and so on.

 

[MSMS3]

Are you still running VTA? That is really messing with the signals your MAF is sending to your ECU and what your ECU is trying to do to compensate. What about the boost controller? Does it hold steady boost with the controller activated? With both the FMIC and the catless exhaust in combo you may be seeing true overboosting, causing the cycling and ECU confusion while running VTA. You also probably need one step colder plugs. You may be getting some knock that is being addressed by the ECU to produce these boost swings.

 

[Sport6]

Check you boost solenoid for any cracks or if the tubes are on all the way. Since the Corksport comes with an inlet, some people have broken the boost solenoid tubes trying to take off the tubes for the install.

 

[Blitzkrieg]

Are you still running VTA? That is really messing with the signals your MAF is sending to your ECU and what your ECU is trying to do to compensate. What about the boost controller? Does it hold steady boost with the controller activated? With both the FMIC and the catless exhaust in combo you may be seeing true overboosting, causing the cycling and ECU confusion while running VTA. You also probably need one step colder plugs. You may be getting some knock that is being addressed by the ECU to produce these boost swings.

My ms3 is stock other then the TIP and SRI, I am recircing the factory bpv, i think your are reading the mods on my MSP, LOL.

 

[Blitzkrieg]

Check you boost solenoid for any cracks or if the tubes are on all the way. Since the Corksport comes with an inlet, some people have broken the boost solenoid tubes trying to take off the tubes for the install.

All of the tubes are intact and seated properly, i am unsure if the boost solenoid has any cracks though its really hard to get a good enough veiw. If the boost solenoid was cracked wouldnt i get boost swings in all gears?

I also noticed today that in 6th gear ill hold 15.5 pounds until i hit 3000rpms and pretty much exactly when 3000rpms hits it starts spiking back and forth

 

[mr_mazda329]

I think the boost solenoid is the problem. I dont think is getting a good vac reading, which may be causing you wastegate to open close quickly. Somethins seems to be not connected right.

 

[Blitzkrieg]

I think the boost solenoid is the problem. I dont think is getting a good vac reading, which may be causing you wastegate to open close quickly. Somethins seems to be not connected right.

Im running out of light right now so im going to pull everything out tomorrow and check everything in detail. If by chance i did manage to break my boost solenoid, does anyone know where i can buy another one? Also is there a scematic somewhere for the the boost lines to the solenoid so i can be 100 sure it is hooked up correctly?

 

[MSMS3]

My ms3 is stock other then the TIP and SRI, I am recircing the factory bpv, i think your are reading the mods on my MSP, LOL.

Sorry, yes. I see. My bad. Did not look closely enough! I agree that rechecking the vacuum lines is the next step. Good luck. Let us know what you find.

 

[Sport6]

Im running out of light right now so im going to pull everything out tomorrow and check everything in detail. If by chance i did manage to break my boost solenoid, does anyone know where i can buy another one? Also is there a scematic somewhere for the the boost lines to the solenoid so i can be 100 sure it is hooked up correctly?

Boost Control Solenoid from OnlineMazdaParts

For the vacuum lines that connect to the solenoid. The line they show in this picture goes to the wastegate actuator. The other "nipple" on the solenoid goes to the actual inlet pipe.

I think something isn't tight or theres a crack in the line/solenoid and you are seeing the boost creeping because theres much more load in 5th and 6th.

 

[Blitzkrieg]

Boost Control Solenoid from OnlineMazdaParts

For the vacuum lines that connect to the solenoid. The line they show in this picture goes to the wastegate actuator. The other "nipple" on the solenoid goes to the actual inlet pipe.

I think something isn't tight or theres a crack in the line/solenoid and you are seeing the boost creeping because theres much more load in 5th and 6th.

Sweet, thnx for the diagram. I was getting aggravated and decided to just pull the car into my garage and try to figure this out now. For the life of me i dont see anything wrong. All the vac lines are correct, there are no tears or pinches in any of the lines and the solenoid doesnt show any signs of cracks. Im stumped.

I also was playing around on the highway and it it seems to be happening a little differently then before. when i first noticed the car doing this it would do it no matter what rpm i was at now it only will do it if i go wot from 3000rpm even. I hopped on the highway and popped it in 6th and punched it from 2000rpm - 4500rom and it didnt do it, then i let off and punched it again at 4500-5000rpm and it didnt do it. i slowed down to 80mph which is pretty much 3000rpm on the dot and punched it and then is started spiking back and forth. i did this like 8 times and it seems to only be doing it from a 3000rpm punch now.

 

[chubbs]

oops you answered my question already

 

[Blitzkrieg]

put anoher 150 miles on the car today and its still sweeping back and forth. How long does it ususally take for the ecu to self adujst if it is the ecu causing this?

 

[MSMS3]

Should have adjusted by now. Something else is going on. Vacuum line leak, defective boost control solenoid, wastegate acting up, etc.

 

[toaofallen]

i had the same problem
i solved it by disconnecting the battery for a good 3 hours (i was i the mall)
connected it and drove it hard but no beating on it
never happened agen

 

[alexspeed3]

I get something similar in vacum...in vid @22 sec

http://www.youtube.com/watch?v=hkHDufXq_cw

 

[Blitzkrieg]

I get something similar in vacum...in vid @22 sec

http://www.youtube.com/watch?v=hkHDufXq_cw

Thats pretty much exactly what it does but in boost, and i can feel the power surging when it happens. I have since put about 350 miles with the mod and it still doing it.

 

[alexspeed3]

I spoke to some guys at a supra dyno meet and they said that its normal, it's some duty cycle stuff that the ecu does to control fuel trims and that it happens in every gear, but it's more obvious in higher gears.

 

[Shadykilla717]

Your problem is pretty simple. I think we need some fact threads on the fact that you need a tune after every mod.... Go on subaru forums and read about this.. With turbo cars you have to tune after the mod so the car will coperate with it. Try the batt reset. Disconnect the battery for bout a minute.. Put it back connected. Drive it for a little while and let the ecu learn the mod. But usually that will only work on NA cars.. You have to tune. Thats why with turbo cars your first mod should always be atleast an AP..

Your having these problems in wot in 5th and 6th because your ecu isnt programmed for all that extra air your getting from the intake..