Fingersmoran

Hello all, I have a 2006 SS/SC with the stock stage 2 pully and tune, GMPP header and exhaust. I live at sea level in greater Vancouver. My problem is when it is cool and dry out, during WOT my engine is loosing power between 4000-7000 rpm, chugging if you will.
We hooked up HP tuners to the computer during a run to see what the engine was doing. Turns out during WOT the engine timing would advance to about 17 degrees then cut it down to 4 degrees instantly. Engine knock? I have tried three different spark plugs including the stock ones and nothing seems to cure it. When the temperature outside goes above 12-15 degrees celcius it runs fine? Anyone know whats going on. This has been a problem with my car since I the stage 2 tune, the dealership doesnt know whats going on.

-shawn

Rodimus_Prime

iTrader: (3)

If anything in the cold you should be making more power due to lower IAT , which means less knock and if your tables are set right more IAT

2K5SS/SC?

Colder air is more dense. The cooler it gets outside, the more air your engine intakes during it's cycles. This causes a leaner A/F ratio than normal which can lead to detonation/knock. When the weather is warmer less air is taken in resulting in a richer condition.

You just need to tune the car with a wideband for the cooler air temps, and that tune will actually be safer when it's warmer out. Easy fix with the HPTuners you were using.

06blackg85ss

iTrader: (1)

you are getting a **** load of KR.... If you are running a 2.8 on the 42/s with any kind of tune you are leaning out hard, especially in the cold.... get biger injectors, or put back on the stock stage II pulley before you blow it up.
**** 13 degree;s of KR is really really bad.

Fingersmoran

i am running the stock 3" pully. everything on my car is GMPP. its very frustrating

i feel having to do HP tune and get a wide band is something i shouldnt have to do seeing how everything i have is GM spec. it should be running great. I use 94 octane gas, new stock plugs and all gm parts.

C0baltWithM0ds

Lemon?

2K5SS/SC?

What is the gap on your plugs?

xravenwingsx

I would check spark plugs/gap, air filter, throttle body, and MAF. if anyone of those are dirty or unserviceable, it can affect your car quite a bit. I too have been experiencing these same problems along with idle surge--picked up throttle body cleaner and MAF cleaner from AutoZone today, so hopefully I'll get to it this week. Dealer did Stage 2 reflashed and it helped a tiny bit, but not much. I replaced and double-checked gap on my plugs but they made little to no difference in my case. How many miles on the car?

As soon as my Injen filter cleaning kit comes off backorder and arrives at my house, I'm going to clean my air filter and install my new hydroshield. 32k+mi on the current filter, I should have cleaned it like 15k miles ago.

Fingersmoran

I was under the impression the stock plugs dont have to be gapped? I have also tried ZEX and NGK plugs and nothing makes a difference. The car has bout 32,000 miles on it. But this has been a problem with the car since my stage II was put in two winters ago. Its not a recent thing.
-Shawn

xravenwingsx

yeah been a problem for mine too, i may just go back to stock for reliability sake and keep the stage 2 kit around if i ever decide to autox.

sscobaltscZ06

Stage 2 with 2.9 pulley, the gm tune only and gmpp exhaust. ran fine all winter long with temps around 35-45 degrees at sea level. No complaints at all here and beat the hell out of it full throttle redline shifts every time it was driven. Dont plan on a tune or cooling mods as the dang car runs just fine the way it is and have to wipe the black soot out of the pipe and edges all the time its running so rich even with the 2.9 pulley.

KillerBee

Sounds like a bad tune. Get someone to tune it good.

eurochevy

and your only complaining about it now? lol... mmm pm sharkey he lives in abby/langly area maybe he can give you some insight.what colour balt you have?

2K5SS/SC?

Get a new set of plugs regular NGK BKR7E $2.00 ones and gap them at .035. Also, clean your MAF with CRC MAF cleaner. Let me know the results.

If this doesn't work then you tune is definitely screwed up. GM Stage tunes aren't that great anyhow, so might want to look into a custom one eventually.

xravenwingsx

If you haven't gotten the reflash yet--go do that, THEN:

Get some STP throttle body/air intake cleaner. remove intake where it connects to throttle body, spray tons of cleaner in there.You're also going to need a soft rag that you don't mind throwing away and a lot of q-tips to clean in and around the butterfly. Mine after 33k miles had lots of BLACK gunk in there. Oil blowby, I assume. Catch can would be a good investment. Works like a charm!!!