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ONLY HITTING 5 PSI! cobb stage 1 OTS tune

5K views 15 replies 6 participants last post by  FXTerrific 
#1 ·
Hey guys,

Got a killer deal on a cobb v3 yesterday and put on the stage 1 93 map. Today, i turn my car on and notice a p0037 check engine light and my boost is maxing at around 5 psi, no higher. (couldve done the same the day I bought it, but wasn't paying attention).

What does this mean? I also have a strange wastegate chatter identical to the video here...

https://www.youtube.com/watch?v=NdpngfRNSRA&index=17&list=WL

Thanks !

Im out to the garage to check the hoses from the bcs now.. dont know much about it so any info on that would be helpful for sure.
 
#2 ·
(couldve done the same the day I bought it, but wasn't paying attention)............
as in the check engine light was on since you bought it? or the low boost?

iirc that code is for O2 sensor related stuff, like a shot sensor, or pinched/ripped harness, etc. did you mess with your exhaust or anything?

what other mods?
 
#3 · (Edited)
low boost.. check engine came on the day after i installed the ap. I have a high flow downpipe and don't think much else that matters in this case (sti intercooler).. bought the car with a few mods so its possible there are other small mods.

Never touched the exhaust, pretty sure its an sti axle back
 
#4 · (Edited)
I have a high flow downpipe and don't think much else that matters....
So the downpipe is not the oem one (with all the heat shields) that came stock?
Does yours have a cat in it still?

Couple things just as a start:
You could (actually/probably should) be on stage 2 map if you have an aftermarket downpipe. Make SURE you pick the right one based on your fuel octane and your other mods (intake?). Info on Cobbs site. https://static.cobbtuning.com/cobbtuningweb/site/maps/subaru/map_notes/SUBA_US_FXT_04-05.pdf
^^^ this part could also play a part in the video clip you linked and your question that sounds like some surging (imo) as far as a mismatch in parts vs tune.


Most often, and in my recent case, that code you saw is due to damage on the wiring for the rear O2 sensor. Maybe check to see if everything is fine or if there's even an O2 sensor installed in the rear location (at the end of the DP) at all. Lots of threads like this:
http://www.subaruforester.org/vbulletin/f87/p0037-cel-code-48409/
Or maybe just coincidence and the sensor crapped out that day.

Seems like either your code was erased and luckily didnt come back until the new map was uploaded, or it was disabled permanently on that previous map, which would need to be redone on current setup in order to pass inspection in most states. Based on the couple mods you mentioned, and possibility of still other mods, its possible the car already had some sort of aftermarket tune on it, with that CEL disabled.
 
#6 ·
Wow, thanks for the great feedback!

And a very embarrassing realization today.. I can hit 11 psi, I just didn't know I had to floor it to get that type of response. So after some more research I realized the boost is on vacuum for cruising, even at decently high speeds (80 mph).

HOWEVER.... I would still appreciate the assistance dealing with the wastegate flutter, and as someone said (sorry i didn't put name, I clicked reply instead of quick reply) that it could be caused by my not being on stage 2. I heard stage 2 is potentially damaging to the engine, and was advised by the guy who sold it to me that stage 1 is the best. Again, just throwing that out there, though I tend to agree with you that stage 2 is better for my car as of now.

I attached a few pics, noticed a nice dent in my (wrapped, guess that's bad for you guys) DP as well as a very rusty sensor...
 

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#7 ·
The flutter is inevitable no matter what you do. You can try to chase it around, but you will fail just as the rest of us have. The extra power was AMAZING when I ran Stage II, but I couldn't stand the flutter, so I reverted back to stock. I tried everything. Only way to get rid of it is to go with a VF turbo or larger.

Stage II, my car was completely transformed and performed like a BEAST. Stage 1 didn't do jack squat for my car.
 
#9 · (Edited)
Just my 2cents...but id always stick with the combo of tune matched to the parts I have installed. Read the stuff in the link inposted to cobbs site, it'll help ya.

I'm not a tuner, or a pro, but if it was my car I'd:
Upload the stage 2/stock intake map for the correct octane I was using.
Drive the car while monitoring the "dynamic advance mult" option on the accessport u bought. What # pops up initially? Does that # change to "1" after a bit of driving? Does it stay there?


The CEL is gonna stay there most likely as u don't have a cat in ur dp. The flutter sounds more like surge to me though. Someone more advanced could chime in....but isn't wastegate flutter when u have a fluttery/whistly/dooo-dooo-doooo upon lifting off after a gentle boost? That video sounded like a chug-chug-chug sound while the turbo is boosting/getting going iirc.
Bit like bluefox said....the flutter u may hear will always be there with a more free flowing dp.

Theres a whole bunch to read on these couple topics, but assuming ur after engine health as u already stated, id do that reading asap and as much as possible.

You'll get it.
 
#11 ·
Ill definitley check out that gauge... and just to clear something up I do have a cat in the dp, its just an aftermarket "high flow" cat.

And wowwwwie... I tried out stage 2 and holy crap I could NOT get the grin off my face.. highway on ramps got 20x more fun. :grin2:
 
#14 ·
good news on the DAM.

for the DP is more a matter of oem vs aftermarket bellmouth section...then the cat imo.http://blog.edoperformance.com/wp-content/uploads/2011/10/DSC_4712-small.jpg

dont really know on the O2 sensor question. while it wouldnt help with it being broken obviously....the front O2 would come more into play with fueling iirc. id check on your AP as well to see the a/f live. wont be terribly accurate...but at least youll know where ur at at cruise and idle speeds pretty close. and at least if it says 10 or 12 or 14 etc when full throttle (all of that on a closed course obviously) youll know roughly were youre at.
 
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