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Old 09-25-2011, 06:31 AM   #1
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white smoke from exhaust smells like fuel

Hey guys just picked up an 87 IROC 5.0, 5 speed and need some help. Car was sitting for a while and had coolant leaks from lower intake manifold, removed intake and replaced lifters and adjusted rocker arms. Inaddition also replace cooling fan switch and coolant temp sensor. Engine is put back together and starts right up after playing with the timing a bit she runs just fine here is my dilema I have white smoke coming from exhaust it smells like fuel and not coolant and my oil and coolant are not showing sings of mixing ( drained old oil and coolant right away to check for contamination when first taking car home). My smog pump is seized so I don't know if this can cause my problems. I was thinking of getting a head gasket stop leak to see if it helps before I go digging into the motor. I figured if the smoke stopped or lessens then I will rip it apart further.. I am new to the forum and any help would be appreciated...
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Old 09-25-2011, 06:49 AM   #2
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Re: white smoke from exhaust smells like fuel

In my experience, excessive fuel would give you black exhaust smoke. In the cases when I had white exhaust smoke, it was always coolant leaking into the combustion chamber without leaking into the oil. This can and does happen with a blown head gasket.
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Old 09-25-2011, 07:52 AM   #3
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Re: white smoke from exhaust smells like fuel

Have you run the car a few miles to warm it up, it's not just overnight condensation in the ex pipe evaporating? Or maybe it's the belt smoking from that seized smog pump lol
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Old 09-25-2011, 10:49 AM   #4
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Re: white smoke from exhaust smells like fuel

It was pretty warm .. smog pump never had belt to begin with..lol. dosent smoke when I drive it or at least don't see smoke while driving just sitting there...
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Old 09-25-2011, 07:27 PM   #5
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Re: white smoke from exhaust smells like fuel

I am helping him fix the car it is currently at my house. Upon start up there is no smoke but when it starts to warm up It will begin to smoke a bit and as it gets hotter it smokes more. But as soon as you give it gas it clears up. It smells rich and is a bluish white color. Oil is clean, coolant Is also clean. There is no smell of coolant leaks anywhere either. A little bit of backstory, when we got the car it had an intake leak and it turned out the intake was cracked/broken at the 1 cylinder at the coolant port. We replaced all the gasket and were able to repair the broken intake. I am not yet convinced it's a headgasket I am thinking leaky injectors and maybe valve seals.

Last edited by camarorsssss; 09-25-2011 at 07:44 PM.
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Old 09-25-2011, 08:13 PM   #6
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Re: white smoke from exhaust smells like fuel

Just to rule it out, give it a health check - pull the plugs and do a compression test, or leakdown test if you can. That will reveal any ring, valve, or head gasket seal problems. But yeah, sounds like a top end problem.
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Old 09-25-2011, 10:13 PM   #7
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Re: white smoke from exhaust smells like fuel

We will do a compression test. Stupid question but could misadjusted rocker arms cause this type of problem
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Old 09-25-2011, 11:42 PM   #8
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Re: white smoke from exhaust smells like fuel

just curious how you fixed the cracked intake. was the flange just cracked, or in more than one place. under hotter temp. there will be more pressure , if you didnt fix the entire crack, especially on the inside of the intake, the excess pressure will push (or draw from the piston) the coolant into the chamber. may have some ring damage too considering the blue color of the smoke. as previously mentioned , it can get in there without getting in the oil. intake could also be warped so bad it didnt seal. what i would do is the compression test, and probebly change the intake too anyway. if it has a crack, it may be craked in other places and a new/used intake is not that expensive. might as well replace it and eliminate that as a possibility.

misadjusted rocker arms will either make it click loudly , or if overtightened it will run crappy cause the valves wont close all the way, then the piston cant compress the gas and air like it should cause it isnt sealed in there. if it is leaking coolant into the cylinder it could cause the gas to not completely burn, making it smell like gas
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Old 09-26-2011, 06:08 AM   #9
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Re: white smoke from exhaust smells like fuel

blue smoke is indicative of oil burning... I second the suggestion to do a compression/leakdown test.
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Old 09-26-2011, 07:20 AM   #10
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Re: white smoke from exhaust smells like fuel

We will def do the compression test to see if there are any cylinders that are low. I would rather it be a headgasket at this point than a ring problem. As far as how the intake was fixed it was almost like the intake was chipped/broken not really cracked and it wasn't all the way through the coolant passage more a surface defect causing it not to seal. It was fixed with marine strength jb weld type stuff by a mechanic. It was smoothed out and was almost good as new and sealed fine, atleast from the outside(no leaks)

Do a dry and wet compression test or would a dry test be good enough?

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Old 09-27-2011, 07:17 PM   #11
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Re: white smoke from exhaust smells like fuel

2 in a row with the same symptoms.

white tail pipe smoke that has a very strong gasoline smell is raw fuel being vaporized in the exhaust. its very flammable, so no smoking cigarettes.

look for leaking injectors or fuel pressure regulator.
first thing to check is the fuel pressure regulator. it not uncommon for them to leak fuel into the intake. any signs of liquid fuel in the vacuum hose is a sure sign its bad.
also in this case, check for a leaking cold start valve if the FPR checks ok.
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Old 10-05-2011, 05:04 PM   #12
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Re: white smoke from exhaust smells like fuel

Yep, sounds just like whats going on with mine. Its running ULTRA-MEGA rich at this point (raw white fuel vapor puffing when I gas it). It's to the point that last time I fired it; the next morning the garage smelled like a can of fuel spilled ... I have checked the injector ohm's and a couple seem to be out of tolerance but I hear them clicking while running. Car hard starts, but runs great and revs out fine. It's just super rich. My CTS ohmed at .929k ohms which was correct for the temp of the coolant, and all my injectors have 12.5 volts to their wiring pins. I also get no codes when shorting the ALDL. I am almost to the point of calling this a stuck open injector because I find no leakage in the FPR vacuum line. Might be time to call Southbay, but I hate to throw parts at it until something sticks.

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Old 10-06-2011, 01:18 PM   #13
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Re: white smoke from exhaust smells like fuel

I had the same problems. Turned out my coolant was leaking into the combustion chambers and on top of that. I had a leaking injector. thus causing the white smoke that smells like gas.
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Old 10-06-2011, 01:28 PM   #14
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Re: white smoke from exhaust smells like fuel

Leaky cold start injector was my problem. Didn't have the smoke but actually hydro locked. Luckily nothing got hurt.
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Old 10-06-2011, 03:46 PM   #15
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Re: white smoke from exhaust smells like fuel

Quote:
Originally Posted by lunaticinaZ View Post
I had the same problems. Turned out my coolant was leaking into the combustion chambers and on top of that. I had a leaking injector. thus causing the white smoke that smells like gas.
Well the smoking has stopped and the rich condition is getting better. I think my injectors were hung open from the car sitting to long. I seafoamed the tank and now it seems as if the injectors are cleaning up some. As of yet, it shows no sign of using coolant. I figured the same so I marked my levels. Now I need to replace my injectors. So was yours a head gasket or an intake gasket?
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Old 10-06-2011, 05:43 PM   #16
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Re: white smoke from exhaust smells like fuel

Just replaced the head gaskets today didn't pit everything back together yet I will keep everyone posted..
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Old 10-06-2011, 08:38 PM   #17
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Re: white smoke from exhaust smells like fuel

Cool man. Did you also do valve stem seals? I know that if they split they can cause more than just start-up smoke. They can smoke under acceleration much like a ring, but not as bad.
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Old 10-06-2011, 09:14 PM   #18
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Re: white smoke from exhaust smells like fuel

How do you tell if you have a leaky injector and how do you find out if your coolant is leaking into your combustion chamber?
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Old 10-06-2011, 09:32 PM   #19
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Re: white smoke from exhaust smells like fuel

As far as coolant leaking into the engine ie. blown head gasket or leaking manifold gasket there are several signs. A head gasket can blow three different ways. It can leak into the block turning the oil a chocolate milk consistency and color, it can blow hot exhaust gases back into the coolant causing an overheat, or it can enter the combustion chamber and exit through the exhaust causing a sweet smell and white steam out of the pipes (not like condensation this is a heavy white steam that stinks of antifreeze). As far as the injector you need a fuel pressure gauge. First test the prime pressure to make sure the pump primes the 40 psi the car needs, if not the pump might be going bad and that is causing a lean condition and the ECM widens the injector pulses to try and make up for it. If the pump primes the full 40 psi. then start the car and make sure you have a running pressure of approximately 38-39 psi. I myself then killed the car and clamped the rubber return line shut and watched my pressure gauge bleed off and I timed it. It took 20 minutes. Im not sure if i'm right with this, but that is way to long so there has to be a leaky injector somewhere. Another thing you can do if you think you have one is to pull the vacuum line off the FPR and see if fuel comes out. That is a sign of a bad FPR and it will cause it to run fat. If there is no fuel from the vacuum line, start the car and pull the vacuum line and make sure the pressure rises to 45-50 psi. That means the FPR is OK. If you have any other questions, feel free to ask.
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