Clown

Let me start by saying that this issue happened out of the blue after not driving the vehicle for a few weeks.

I am running a Rogue C-Tune, larger turbo, full 3" exhaust, DP Wastegate.

I have been running the above setup for quite sometime now with no issues.

Lately out of the blue the car would not build boost smoothly running anything over 15psi. The boost gauge hesitates or hiccups once passing 15psi and then eventually hits 18psi which is the max I run, but it doesn't sound good and makes a funny noise and there is power stutter. This happens in any gear and ONLY over 15psi on the guage.

If I run anything under 15psi I have no problem whatsoever in any gear.

I beleive that it is either a MAF Sensor problem or I may have a vacuum leak. I think that it is an electrical issue and not a mechanical issue personaly and was wondering if anyone had any ideas so I can start looking in the right direction.

I took the MAF off and IC pipes off and inspected the turbo which looked and felt great. Put everything back on and tightened everything really good checked the vacuum lines and they all are attached. Took the chip out of the ECU and put it back, unplugged the Rogue MAP sensor and plugged it back in. Changed the spring in the blow off valve....Still no change


Any thoughts would be appreciated THANKS!

User 52121

Running lean? Got a wideband?

Clown

Ya I have a wideband. I beleive that AFR were normal last I checked but will definately look into it. I think a video of the boost guage and wideband guage is in order....I will try to throw one up soon so you can see and hear what is going on. Thanks

blown 944

Could be Ignition related due to the denser air.

MooreBoost

spark plugs?

pontifex4

I would guess spark, as well. How are the coil, cap and rotor?

Paulyy

Check them all

Clown

Ok thanks guys. I really appreciate your input. I will check the entire ignition system out.

Just curious why ignition would be doing this only over 15psi?

Paulyy

Spark is to weak to burn the fuel and bogs out.

This happend to me, i couldn't get over a certain amount of boost (not sure how much it was) and i changed the plugs and leads, helpt a little. then realised my rotor was finished so i changed the cap and rotor and it solved the issue. I knew it wasn't the coil because it was a MSD Blaster and was quite new.

blown 944

Cylinder pressure is higher and weak spark will show up when the air is more dense.

Try gapping your plugs down to .025 and report back.

Tom M'Guinn

My money's on ignition too -- plugs, gap, cap, rotor, wires. Don't overlook the spark plug wires -- they bake under the hood and are as likely a culprit as any.

fejjj

Mine was doing the same thing. Replaced cap and rotor and problem solved.

Black51

Contrary to popular vote, I'm gonna go out on a limb here and say it's the flux capacitor.

Clown

I tried taking some video but not sure if it is worth posting. Just took another drive and noticed the in the video that when it gets above 15psi in the trouble area and hammering on it the AFR is 12 or 13. When the car was running fine at full boost the AFR was around 11. Its hard to take video because I am jolted foward when the car gets over 15psi and then hits a boost wall. I will pull the plugs and gap them and check the rotor and cap next. Thanks guys

Clown

Ok here is a video link that I posted on Youtube.

http://www.youtube.com/watch?v=0zo36...ture=youtu.wbe

Listen for the sound when over 15psi you may have to turn your speakers up. Also check out the AFR I am on the pedal full throttle in third gear and it should be getting 18+PSI under normal operation and hold be holding it there. When the car was working fine at max boost and full throttle the AFR was around 10.8 to 11.2 AFR now it is closer to 13 or 14 AFR??