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Hi all,
im getting some light smoke from the exhaustml. My car is cammed with catless exhaust. I stsrted noticing this after last oil change...could it be too much oil??
I read in another thread a member with a c6 posted a video..smoke looked identical to whats happening to my car. Turned out he had one bad valve stem seal...
it keeps coming even after the car has been driven for 20 mins. color looks dark grey/md grey. i'm not sure. Do you have a scan tool
i also just checked the oil level and it went down about an 1/8th of an inch.
It also obviously smells like gas. since i did the cam install it stinks of gas. I got it tuned, same thing.
Black smoke is not ALWAYS fuel color...raw unburned fuel would look white/gray like you said...how is the car running ??....running rougher...might be hard to tell with that cam ??...misfire ??...do you have a scan tool to look at fuel trims ??...I bet your running a little LEAN..,your fuel trims are probably running around 10-15 %...this raw fuel will NOT make the car run rich as far as the O2 sensors are concerned...a BIG misconception !!...O2 sensor doesn’t “see” this raw unburned fuel !!...you might have an ignition problem...check it out !!
yeah the car is very rough. Ms4 cam is pretty.big and my tuner hasnt been able to get it.running smooth. Most of the time it dies if i turn the ac on and the car isnt moving.
yeah the car is very rough. Ms4 cam is pretty.big and my tuner hasnt been able to get it.running smooth. Most of the time it dies if i turn the ac on and the car isnt moving.
Do you mean P0153 ??... "O2 sensor circuit slow response" bank 2 sensor 1...if you don't have an exhaust leak upstream of the sensor 1 O2 it's 99% bad O2 sensor...in the pic I've included you can see how "lazy" the sensor on the left is switching....should look like the right...if you have a scan tool that can graph the O2's you can see for yourself. STICK WITH OEM O2 !!!...do you have mechanical background ??...you can disconnect each plug wire at the coil and see if you have a good spark from the coil to a 12v test light connected to a good ground...you should have a good strong spark (about 1/2 - 3/4 inch)...You also can ohm out each plug wire...I forget what the resistance is off the top of my head...maybe someone can chime in...if everything looks good you can pull each plug and check for cracks in the porcelain etc... This is what it sounds like but I don't like to troubleshoot based on "symptoms"....just the evidence !!...The tuner can't get it to run smooth with a potential ignition problem.
so are you saying this type of smoke can come from running to lean? My car really smells of gas. Logic points me to rich, or is that out of the question?
also, what scanner are you using? Is there a "best" scanner for our cars?
my mechanical backround is ok. I did all the cam.instal and oil pump che trunnion dual springs myself with the aid of this forum. Im just kinda lost with electricity...
so are you saying this type of smoke can come from running to lean? My car really smells of gas. Logic points me to rich, or is that out of the question?
also, what scanner are you using? Is there a "best" scanner for our cars?
my mechanical backround is ok. I did all the cam.instal and oil pump che trunnion dual springs myself with the aid of this forum. Im just kinda lost with electricity...
No, it's coming from raw unburned fuel...no ignition in one or more of the cylinders. It's not burned so technically it's not rich... Raw unburned fuel is not "seen" by the O2 sensors...it HAS to be burned...it is just occupying space within the combustion chamber compared with the oxygen in it...a fuel injector not firing will make the space inside the combustion chamber REALLY filled with just oxygen so it's even leaner !!...understand ??...I know it's counter intuitive but maybe I'll do a YouTube video to show this...I can shut off an injector and then a coil with my scan tool and show how the fuel trims respond...lean with no ignition...really lean with no fuel !!….by looking at just fuel trims you can tell if it's maybe a fuel misfire or ignition misfire. You can buy a Bluetooth scanner for $100.00 that hooks up to your cell phone...you can get a "clone" GM Tech 2 for $400.00 to a Snap on Verus Pro for $7,000-$8,000. I have an Autel MS906 which is about $1,100 but I also use in part time diagnostic gig...when I have time...which is not much...I'm still working full time !!...at least for another 2-3 years anyway...these last 3 scan tools are "bi-directional" which means you can command it to turn on your fuel pump, cooling fans, EVAP solenoids, and they show a LOT more data PIDS...this REALLY helps to diagnose. Without one (and some basic diagnostic knowledge) sometimes it comes down to just firing the "parts cannon"...if I had a dollar for every O2 sensor, plug and wire that's been changed by Forum members needlessly I'd be a Zillionaire. Electricity is not hard...compare it to water flowing in a pipe...a bigger pipe can flow more water...a bigger wire can flow more current...as far as buying a scan tool it comes down to your pocketbook...these C5's aren't getting any younger my friend !!...maybe someone on the forum can tell you if they like their Tech 2 if they are reading this. Let me know if you need any more info !!
My experience has always been that valve stem seals generally smoke more on start up and on deceleration, less so running down the road.Compression check is still cheap way to know the rings are good. Obviously they should be, but seriously rich can mean oil washed off cylinder walls.
Is it possible having the oil level too high for a while can cause something like too much pressure and oil going into the intake and getting into the combustion chamber?
Is it possible having the oil level too high for a while can cause something like too much pressure and oil going into the intake and getting into the combustion chamber?
I've never seen that. The crank can splash oil and drag -- not good either -- but the rings should still pull cylinder wall oil back down. When you say your tuner can't get it to run smooth -- do you mean run, or idle?
You pretty sure you're seeing the dipstick level go down?
Ok just inspected the wires quickly.. cylinder 3 wire has a funny white mark on it..like shorting or something
and cylinder #2 the plug is loose!! I destroyed the wire when trying to remove it. The plug was finger tight... i swear i torqued them all down to 10 ft-lb. Heres what that plug looks like.
Should i install a new one and should i follow NGK specs for torque or GM?
hopefully this is part if the reason im getting smoke.
Always use MFG specs !!..,Just to be safe I’d change it... I’d also inspect the rest and wires. As far as the possible bad wire you can hook up a test light to a good ground and run the engine...bring the tip of the test light close to the mark on the wire and see if you can see a spark jump...the spark wants to take the path of least resistance so it will go to ground through the test light or you can wait till dark or bring the car into the garage if you have one and spray the wires and coil with water...if there is some faulty ignition components it will look like a mini lightning storm under the hood !!
09-08-2018, 09:18 AM
Smoke from exhaust
