Dustin24

i have a 2008 cobalt ss and the cel turned on and i pulled the codes and the p2178 came up too rich at idle or accel. anyone have any ideas whats causing it? the code seems to be intermittent could it be bad MAF, MASS, or a fuel regulator sensor? i dont know of any solutions on here for this code.

Sl0wbaltSS

Tune. Me getting one fixed it.

Dustin24

i am tuned with bolt ons i had a guy with a trifecta tuning cable do it and was doing awesome until a about a month ago

exninja

iTrader: (1)

Did you try cleaning your maf and map sensors yet?

tomj77

iTrader: (2)

Ur fuel trims above more than -17 to -24 that would be a big boost leak or a bad tune. Trifecta ecp tune did that to me with the Opel injectors, that and their awful tuning. Hptune fixed that issue

Dustin24

yeah i cleaned the maf but made no difference. cleared the code took it a while to come back but ran good for about 10 minutes then went back into limp mode.. i don't want tot pay for a new tune not knowing what my issue is i have a local dyno with hp tuners and hes gonna run me $550 for a dyno tune but before then i want to resolve the issue and install the gm 3 bar map sensors

tomj77

iTrader: (2)

Check for boost leak first. Could have a big one

Dustin24

Should I smoke test it or just use the old soap and water method?

tomj77

iTrader: (2)

Make or buy boost leak tester. Pressurize the system to whatever u boost to and see if u can hear air leaking out anywhere, then soap and water to pinpoint

Dustin24

So you think it's a boost leak if anything? Not a sensor or something? It starts very hard and isles rough in the morning, but when up to temporarily it isles fine.

tomj77

iTrader: (2)

It could be anything, gotta start at square one and eliminate the most likely, cheapest possible causes and move on from there

ECaulk

iTrader: (6)

Boost leak test is quick and easy. Also costs little.

You could try disconnecting the evap and see if that helps.

tomj77

iTrader: (2)

Ya that's right, evap can cause issues as well

Area47

put a shield by your air filter. the A/C being on at idle is triggering the fan to come on and is forcing more air than the maf is calibrated for. thus triggering the code.

ECaulk

iTrader: (6)

I'm going to have to remember this.

slapbetcommissioner

iTrader: (3)

Like the rad fan is pushing air into the intake?

Im also chasing this issue.

I still need to boost leak test.

Dipped_Cobalt

both of these seems like easy fixes...

btw: in your sig, did you mean aesthetics?

slapbetcommissioner

iTrader: (3)

Yep

Dustin24

today i figured out the issue and my map sensor was completely dead and i still have yet come to the bottom of the p2178 code but i think the cause of it was the map sensor going in and out and finally it just quit. we will find out when i replace the ensr if it fixes the issue also i found a ton of resistance across my exhaust camshaft actuator which i will also be replacing.

slapbetcommissioner

iTrader: (3)

I disconnected my evap sel and it feels like a completely different car, hasn't driven like this in two years.
Checked the selenoid itself last year but the selenoid itself seems to be working. So I'm not sure If it's the actual selenoid causing the issue.

Fingers crossed I won't see anymore 2178 codes.

Popped the 455 code and the car stumbled a bit on cold start today but imediately smothers right out.
With the Ac on yesterday the car was smoother ten it has been in a long time.

Area47

Thje only time i see the code pop up is with the ac on at idle. idle trims before a/c is turned on, less than .8 +/- {it can be done}, a/c on bam +18% Just 50 rpms above idle, it goes away.

It also may be a dead spot in the intake designs as well.

Dustin24

Where is the evap located?? Code came back!

T-fog

I was chasing this code for a bit, My issue was my evap purge solinoid on the IM...There is a picture of part in this thread to help you locate it>> https://www.cobaltss.net/forums/2-0l...cement-235483/

Long story short I replaced it and it didn't solve my issue, Threw some more money into the car with no prevail eventually I pulled the sensor a second time to bench test and inspect....When I pulled it I found that the rubber seal/ring had a very tiny little nick in it.. When i say tiny I mean tiny lol, After I bench testing to ensure proper function of the sensor, I then went out bought a new rubber ring/seal and then I installed it with a new ring/seal and no more Cel.

Hope this helps, Keep us posted

Dustin24

So if I dissconect it should the car act any doffernt should it spit and studded on cold starts bad run normal when the cool at temp is above 110 degrees? The car pops and backfires on decel and on accelerated lags and stuffers at low rpms

Dustin24

Okay I pulled it and there is a tiny tiny little slit in the o ring it came out pretty hard I just put a little oil on it to reinstall it and keep from tearing it anymore like it was the absolute smallest thing ever.. that can be causing the p2178 code and making car go into limp mode? Making it laggy and backfires on deceleration?? That tiny little tear in o ring