Alright so tonight I get in the car to go pick up some Taco Bell (awesome, ikr) and it drives normal and all. I get in the drive-thru, and at idle, my tailpipe starts pouring out white smoke. I drive home like normal and it doesn't smoke the whole way home. I get home, start idling again, and smoke starts pouring out. I smelled it, and i'm pretty sure it smells sweet, which would indicate the burning of coolant. Since it only does it at idle, I would assume that rules out the head gasket. Temperature gauge is normal the entire time. It has done this before, but it's only been a tiny insignificant bit of smoke until tonight. I'd also like to add that it is foggy outside tonight.


Could the IACV be busted and leaking coolant into the intake manifold whenever it opens up at idle?

 

Have you checked the radiator and reservoir for gas bubbles and oil and the oil for coolant?

Have you done any recent work that might explain the problem?

 

I'll go check right now.

Only work i've done recently is that I changed the spark plugs because they were fouled. Me and Marty determined that they were probably fouled from the Seafoam I ran through my engine a while ago.

 

Alright, I just went and looked.
1. Coolant still looks just like it did after I flushed the system a month ago when I changed my timing belt.
2. Reservoir isn't missing any coolant at all.
3. Oil is normal
4. IACV isn't leaking


I idled the engine and could not get it to to spew out smoke again.

I'm thinking it may have had something to do with the moisture in the air... not sure.
Also, i'd like to add that I had the A/C temp slider on heat for the first time in a while.

 

What was the outside temperature when you saw the white smoke? Was the engine cold?

 

Outside temperature was about 61 degrees.
Engine was fully warmed up, and I had been sitting in Taco Bell drive thru for a couple minutes. It's a 10 minute drive to Taco Bell, top speed I ever hit on the way there was 45-50. (~speed limit). Didn't drive it hard at all. Never went above ~3300RPM.

When I got home and was inspecting it in the driveway, it was a lot less smoke than at Taco Bell. Now it is no smoke. When I was inspecting it after I got home from Taco Bell it wasn't all that sweet, only a little bit. Now it is still sweet but nowhere near what it was before.

Oh yea, and I did a compression test a few weeks ago... from cyl. 1 to 4: 200, 195, 196 195

 

Alright, I just went out again and tried.
It's 75 degrees right now and it smokes during all RPMs. However, I have not yet been able to replicate what happened at Taco Bell. When I was at Taco Bell my exhaust was creating a heavy cloud of smoke... Right now the smoke gets about 2 feet from the tailpipe and dilutes into the air.
Also, it doesn't smell sweet anymore at all... it smells like fuel.
Am I probably running rich and that's all?

But still, the fact it smokes at all worries me.
Here's some videos I took to give you a better idea.

 

looks like its burning coolant to me... but I got nothin' as to why its only doing it at idle.. there is the most engine vacuum at idle, makes me think its something in the cylinder head, but there isn't much coolant up there... sure the iac valve is ok?

 

IACV is definitely fine.

On Honda-Tech I was told it might be valve seals... a user recommended I run some Lucas oil stabilizer in my next few oil changes. He said his old Jeep had this problem so he ran the Lucas for a few thousand miles and it never smoked again after that.
I went and bought some and put it in... I'll have to wait and see the results.

I think that the other night it was smoking like normal and the odd temperature/climate was exaggerating the amount of smoke.


I think it may be running rich though. Notice in the video that when I rev the engine smoke is still coming out, but as soon as I let off the gas and the throttle plate closes shut, the smoke stops for a second, and then returns once it begins to idle again.
Think about it this way...
The engine is adding too much fuel at idle. I rev the engine, and it continues to add too much fuel through the powerband. I let off the gas completely and the ECU starts dumping in the amount of fuel it would at idle, but since the RPMs are still up, the fuel is getting used.
At least that makes sense to me... i'm not sure how right it is.

 

Trust,

Regarding exhaust smoke:
White = coolant
Bluish = oil
Fuel = black

I think the bad valve seals idea is reasonable, if your exhaust smoke is bluish (=oil). This would also fit with the fact that your cylinder compressions are fine.