Idle surge after Stillen supercharger install

imazman

I have an 11' 370z nismo with installed Stillen SC and oil cooler. I bought the canned tune from Stillen and for what it's worth I too have an occasional P0300 pop up. I want to make a few mods and then I hope to get it to a tuner soon which will hopefully fix the problems I'm having with the shitty Stillen SC kit.

NissanTracker

I ordered some material for a shield... I'm going to make an attempt this week to get it done. I'll switch out the TB's as well. I just haven't had the time.

My last resort will be back to the tuners, but this will wait until the spring. I'm considering TopGunz A-A kit and would rather just put that on and re-tune. I have a true dual exhaust as well to install.

Having the MAFs so close to the filters is just a terrible design. You normally want them closer to the T.B's. Especially when there is a difference in Temperature. Maf's are reading directly after the filters... then goes through the charger and maybe not significant, the air temp/density is not the same. I have a feeling this initial design has something to do with their CARB certification.... as well as the crappy in house tune

I talked with someone that mentioned that this Stillen S.C. kit, if installed by a SAE certified tech at Nissan, will not void the factory warranty. Have to use the Stillen tune to stay CARB compliant

overtureZ

In for the results.. I am also having this issue. Definitely when my car is up in temps

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Auto/Z Enthusiast - Mechanical Engineer - Fabricator - Do it for dale

RadioFlyer

Another option is to extend the intake with sections of the Y pipe to mount the filters onto. I've thought about doing this, but never really needed to. But my thought was to buy piping from Pep Boys or Home Depot, either a 3" exhaust pipe section, or pvc from the plumbing section, and cut it into two 10-12" pieces, and get two silicone couplers. You're still pulling from right in front of the radiator, but the filters would be on the right-side of center instead of the left-side. But you'd have a decent length of straight pipe before the MAF takes it's reading, so it would eliminate this variable.

Caveat here is that I don't use the Stillen heat exchanger, so the front of my radiator is the same on both sides. YMMV if you're using the Stillen unit.

Another comment, about how it happens more when the car is warmed up, have you guys monitored IAT (Intake Air Temp)? I monitor that on my car, and it heatsoaks really bad when sitting in traffic, or if the car is parked for 30mins to an hour. What I've seen with ambient temps around 80*F, is that if the car is warmed up and driving around, the measured IATs are about 5* higher than ambient. But when you park and get back into the car, IATs are commonly in the 120*F range. Sitting in traffic, I see around 105-110* IATs. This results in whacky fuel trims, definitely different fuel trims than IATs in the 80-90* range when the car is just cruising without traffic. The constantly changing fuel trims seems to be a source for the idle surge for my car. In other words, the car hunts for a way to stabilize AFR at 14.7 while idling, and it does this by adjusting the fuel trims.

My current running theory is that the ECU is logging the fuel trims for each condition it sees (idle RPM/high IATs), and eventually, it will have the data stored, and it will just go to that fuel trim and idle correctly the next time it sees the same conditions. It's sort of playing out like that, but not perfectly. I'm trying to give it more time on this reflash.

NissanTracker

I have a 350z Vq35HR motor (07) and that kit actually comes with only 1 pipe with 2 maf's. I may consider this as well.

I have one of the larger units from frozenboost type 101.

This is a good point. I have not been monitoring IATs. I'll have to take a look. If IAT's increase, the fuel trims are obviously going to change... and the idle surge will occur if it needs air.

overtureZ

Possibly look into doing a PCV delete/catch can system.

I am going to try and do this to maybe fix my surge, and it is also very beneficial to the engine.

Question, When you have the idle surge, does your vacuum flutter, and do you run rich?

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Auto/Z Enthusiast - Mechanical Engineer - Fabricator - Do it for dale

NissanTracker

I added a catch can... but I did not delete the PCV.


When i notice idle surge, 80% of the time I get the p0507 ISC. The fuel trims are increasing... so i actually have a lean condition. From my cheapo logger (NDS or Torque Pro) I see STFT's increase when the fans kick on.

Unfortunately, I still have not found time to rip the front bumper off.

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Diagnosing with Fuel Trims
Fuel trim can be a valuable diagnostic tool - Eastern Manufacturing


Fuel trims can help you zero in on the problem, especially when there are no other trouble codes present. Knowing whether a vehicle is running too rich or too lean will help narrow down your diagnosis. Fuel trims that differ greatly from one cylinder bank to the other will also point you in the right direction. Always evaluate fuel trims at idle and at 2500 RPM.

Running too rich – High negative fuel trim corrections can be caused by MAF sensor problems, high fuel pressure, leaking fuel pressure regulator diaphragm, faulty evaporative emissions components, leaking injectors, defective O2 sensors, exhaust leaks/pinholes before the O2 sensor, coolant temp sensor problems, and base engine issues such as low compression and incorrect camshaft timing.

Running too lean – High positive fuel corrections can be traced to MAF and O2 sensor faults, vacuum leaks from intake gaskets/hoses, unmetered air (intake snorkel leak), clogged or dirty fuel injectors, fuel delivery issues, and exhaust restrictions such as a clogged catalytic converter.

NissanTracker

With the warm weather, I started working on the Z again. I got rid of the P0300 and p0507 by replacing the throttlebodies. Idle surge is now directly related to the fans kicking on. I'm solving it with a new charge pipe with the MAFs closer to the throttle bodies. This effort can be tracked here:

Advice new style Stillen S.C. Intercooler pipe (MAFs at TB)

NissanTracker

... and p0300 is back. Looks like this is a cold start issue. I'm 1000% convinced it is in the tune. I'm dropping it off this week for a tune, so I'll mention it.

NissanTracker

I cleared the cel the other day and it didn't come back until today. The past couple days have been warm out. I now suspect that it is cold starts when it is cold out... too much air causing a misfire?

Chuck33079

There might not actually be a misfire. P0300 is a catch all code when the ecu gets confused. It can be 1000 different things triggering it. When it was cold, I would get it because the flywheel would rattle and trick the ecu into thinking there was a misfire. I ended up having the code turned off. There are codes for the misfires of the individual cylinders, so it hasn't been an issue.

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

NissanTracker

Some updates:

1) Replaced the throttle bodies with brand new ones
2) Moved the MAFs closer to the throttlebodies (revised piping)

Advice new style Stillen S.C. Intercooler pipe (MAFs at TB)

3) netted 25 extra wHP with AFR 10.5.
4) GODDAM p0300 is back. Tune shop states that the Z is trying to hit an idle target of 700, it bounces at around 780, then cel comes on. Went through the idle relearn several times

The voltage on the throttle bodies were checked and what would be the drivers side, which has the T.B. extension, is seeing lower voltages than the passenger side w/o the extension. If the passenger side is .80, then the driver's side with Extension is .74.

I am going bananas over this. So possible that TB extension is an issue?

Chuck33079

Yeah, many people have had problems with the Stillen wiring.

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2011 MB Touring-Sport-6sp-Nav/GTM TT/FI TT TDX/JTran/Kosmic/Eibach/Hotchkis/SPC/CSF/RPS/SoThatsWhereAllMyMoneyWent

NissanTracker

I'll just elimiate the cable harness and add my own wiring. I thought I had Stillen's revised harness. But for sure, if there is a resistance change on the harness, the ECU is going to report a different voltage.

ihiryu

Just for curiosity's sake, do you have pics of yoru piping completed? And how is your idle now?