White smoke on start up - Page 2

swisstyphoon · 12-04-2021, 02:49 AM

Black smoke, and light smell of gas is normal, but not white, and really bad fuel smell. It could very well be a leaking injector! Have the dealer check it before you damage the engine. In the worst case it could hydro lock the affected cylinder. Do you notice any oil thinning? Gas smell on the dip stick? Rough idle? Does the rail pressure drop alot sitting over night, or after a couple of days? Fuel trims that are off?

Rayvan · 12-04-2021, 09:52 AM

Pull the dipstick out and smell it. If it's a leaky injector, your oil will smell of fuel.

Camaro fanboy · 12-04-2021, 10:15 AM

Quote:

Originally Posted by BlaqWhole

It does not sound like anything is out of the ordinary. If it happened all the time and didn't clear then that would worry me. But it seems like it is happening only at initial startup and only after sitting for a week. Even tho you're in desert climates you can still get condensation if it sits overnight and definitely after a week of sitting. Or so I would think. The fuel smell is at startup because gas powered engines tend to run rich at first start since they are in open loop. Which is also why the EGR system recirculates exhaust gases thru the intake to help warm the intake quicker so it can get into closed loop. Also at startup you'll notice the engine RPMs are a little higher for those first few seconds. Sorry if my explanations are a bit jumbled but I've had a LOT to drink tonight.

Anyway, it all sounds normal to me. The engines and ECUs are soo sensitive these days that if you did have an issue then you would have seen a CEL and reduced power mode. Or you for sure would see billowing clouds of smoke and it would just get worse. As well as your coolant would decrease. None of that is happening so I'm of the opine that it is just initial start after a week of sitting and collecting condensation.

Take it for an extended drive and get on it a few times and enjoy it and see if you have any issues.

this

SFV1LE · 12-04-2021, 10:23 AM

Is your car modded? You said “I’m not using any coolant”, you meant not “losing” coolant right? I assume you use coolant vs straight water.

AZ_SS · 12-04-2021, 03:16 PM

Quote:

Originally Posted by swisstyphoon

Black smoke, and light smell of gas is normal, but not white, and really bad fuel smell. It could very well be a leaking injector! Have the dealer check it before you damage the engine. In the worst case it could hydro lock the affected cylinder. Do you notice any oil thinning? Gas smell on the dip stick? Rough idle? Does the rail pressure drop alot sitting over night, or after a couple of days? Fuel trims that are off?

The car runs fine, no fuel smell on the dipstick or noticeable thinning of the oil. I have no way of measuring rail pressure or viewing the fuel trims.

AZ_SS · 12-04-2021, 03:18 PM

Quote:

Originally Posted by SFV1LE

Is your car modded? You said “I’m not using any coolant”, you meant not “losing” coolant right? I assume you use coolant vs straight water.

Correct, I meant the coolant level has not dropped. The only mods are a catch can, Soler TB and Cordes intercooler tank.

BlaqWhole · 12-04-2021, 04:22 PM

It doesn't aound like it is "white" smoke. It sounds like you're just seeing smoke that is consistent with condensation. Again, it doesn't sound like there's anything wrong. No performance loss or coolant loss. No hesitation or stuttering or misfires or anything. No overheating. Again, sitting for an entire week will cause some smoke associated with condensation to pop up on initial startup. A blown head gasket would present itself with other symptoms. You're net even getting a CEL or going into reduced power mode.

Check your hoses, lines, wires, connections, etc. Maybe pull the plugs and unspect them. Drain the oil and inspect it. If there's nothing out of the ordinary then it's just good ole harmless condensation.

LT4Greg · 12-04-2021, 09:38 PM

I’m thinking it’s condensation coming from the engine. Mine had it this morning when I started it to go on a road trip. I haven’t driven it for about 5 days and the condensation was gone after the engine warmed up.

Camaro fanboy · 12-04-2021, 10:54 PM

Quote:

Originally Posted by AZ_SS

The car runs fine, no fuel smell on the dipstick or noticeable thinning of the oil. I have no way of measuring rail pressure or viewing the fuel trims.

mine did that within 5 minutes of changing the oil..

WhiteMale · 12-06-2021, 06:41 AM

Ive observed a little blue smoke on the occasional startup but when I looked in to it a little smoke on startup with the LT1 wasn't uncommon or a problem.

SJFGTO · 12-06-2021, 06:59 AM

Quote:

Originally Posted by BlaqWhole

It does not sound like anything is out of the ordinary. If it happened all the time and didn't clear then that would worry me. But it seems like it is happening only at initial startup and only after sitting for a week. Even tho you're in desert climates you can still get condensation if it sits overnight and definitely after a week of sitting. Or so I would think. The fuel smell is at startup because gas powered engines tend to run rich at first start since they are in open loop. Which is also why the EGR system recirculates exhaust gases thru the intake to help warm the intake quicker so it can get into closed loop. Also at startup you'll notice the engine RPMs are a little higher for those first few seconds. Sorry if my explanations are a bit jumbled but I've had a LOT to drink tonight.

Anyway, it all sounds normal to me. The engines and ECUs are soo sensitive these days that if you did have an issue then you would have seen a CEL and reduced power mode. Or you for sure would see billowing clouds of smoke and it would just get worse. As well as your coolant would decrease. None of that is happening so I'm of the opine that it is just initial start after a week of sitting and collecting condensation.

Take it for an extended drive and get on it a few times and enjoy it and see if you have any issues.

^^^^This x 2^^^

JasonGofast · 12-06-2021, 04:35 PM

Is it oil? I have had 3 different smokes come from my exhaust on start up.

1. The first would come out everytime I cold started the car. Would linger and fill the space. Strong smell. Relatively thin smoke. It was oil from my full catch can getting into the intake and being shat out the exhaust.

2. The second I needed to tow my car. It was a thick white, sweet smoke. It was coolant from one of my heads cracking. My car is heavily modded though and the heads ported so not likely in your case.

3.Rich fuel? My car won't shoot out smoke, but after 10 seconds or so of starting up some fuel can be seen coming from the exhaust. The smell isn't particularly strong and will go away after some driving. Is normal. Especially since my car is catless.

Either way I'm sure you know your car well enough. If it wasn't doing it before and is doing it now it's worth looking deeply into. Perhaps next time you start it you can record and a better opinion can be given.

12-04-2021, 02:49 AM	#15
swisstyphoon Former GM Technician Drives: 2018 ZL1 A10, 06 Silverado Duramax Join Date: Sep 2009 Location: Switzerland Posts: 400	Black smoke, and light smell of gas is normal, but not white, and really bad fuel smell. It could very well be a leaking injector! Have the dealer check it before you damage the engine. In the worst case it could hydro lock the affected cylinder. Do you notice any oil thinning? Gas smell on the dip stick? Rough idle? Does the rail pressure drop alot sitting over night, or after a couple of days? Fuel trims that are off? __________________ 2018 Camaro ZL1 A10 Rotofab Big Gulp, Nick Williams 103, Magnuson 2650, 9.17" (14%) lower, 90mm upper, Vengeance Racing Heads (LME) Cam Package (Cammotion Stage 1), Johnson Lifters, DSX dual intank pump, Lingenfelter high flow check valve, Motion Raceworks Flex Fuel adapter, LPE Big Bore Hpfp, XDI 30% Injectors, BBK shorty headers, Custom 2.75" down pipes, Gesi Gen2 high flow cats, MM catch can. 2006 Silverado Duramax Diesel MPI Compound Turbo 40% over Injectors Efi Live DSP5 Tuning Follow me on Instagram: SwissZL1

12-04-2021, 09:38 PM	#22
LT4Greg Drives: 2017 Camaro ZL1 Coupe Join Date: May 2016 Location: Georgia Posts: 5,872	I’m thinking it’s condensation coming from the engine. Mine had it this morning when I started it to go on a road trip. I haven’t driven it for about 5 days and the condensation was gone after the engine warmed up. __________________ ZL1 Coupe, PDR, Exposed carbon fiber hood insert, My Link with Nav, M6 6 speed and Silver Ice Metallic. Mods done: ceramic window tint, GM Accessories Camaro floor mats and Roto-Fab CAI.

12-04-2021, 09:52 AM	#16
Rayvan Rayvan Drives: 2018 1SS1LE, Silver Ice Metallic Join Date: Dec 2018 Location: San Jose, CA Posts: 276	Pull the dipstick out and smell it. If it's a leaky injector, your oil will smell of fuel.

12-04-2021, 10:23 AM	#18
SFV1LE Drives: 2018 Hyper Blue ZL1 1LE Join Date: Dec 2018 Location: CA Posts: 1,365	Is your car modded? You said “I’m not using any coolant”, you meant not “losing” coolant right? I assume you use coolant vs straight water.

12-04-2021, 04:22 PM	#21
BlaqWhole Account Suspended Drives: 2017 Camaro ZL1 A10 Join Date: May 2012 Location: NJ Posts: 7,692	It doesn't aound like it is "white" smoke. It sounds like you're just seeing smoke that is consistent with condensation. Again, it doesn't sound like there's anything wrong. No performance loss or coolant loss. No hesitation or stuttering or misfires or anything. No overheating. Again, sitting for an entire week will cause some smoke associated with condensation to pop up on initial startup. A blown head gasket would present itself with other symptoms. You're net even getting a CEL or going into reduced power mode. Check your hoses, lines, wires, connections, etc. Maybe pull the plugs and unspect them. Drain the oil and inspect it. If there's nothing out of the ordinary then it's just good ole harmless condensation.

12-06-2021, 06:41 AM	#24
WhiteMale Drives: 23 ZL1 A10 Rapid Blue Join Date: Aug 2020 Location: MO Posts: 2,257	Ive observed a little blue smoke on the occasional startup but when I looked in to it a little smoke on startup with the LT1 wasn't uncommon or a problem.

12-06-2021, 04:35 PM	#26
JasonGofast Used to own a ZL1 Drives: '16 Z06 Join Date: Apr 2020 Location: TX Posts: 279	Is it oil? I have had 3 different smokes come from my exhaust on start up. 1. The first would come out everytime I cold started the car. Would linger and fill the space. Strong smell. Relatively thin smoke. It was oil from my full catch can getting into the intake and being shat out the exhaust. 2. The second I needed to tow my car. It was a thick white, sweet smoke. It was coolant from one of my heads cracking. My car is heavily modded though and the heads ported so not likely in your case. 3.Rich fuel? My car won't shoot out smoke, but after 10 seconds or so of starting up some fuel can be seen coming from the exhaust. The smell isn't particularly strong and will go away after some driving. Is normal. Especially since my car is catless. Either way I'm sure you know your car well enough. If it wasn't doing it before and is doing it now it's worth looking deeply into. Perhaps next time you start it you can record and a better opinion can be given.

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