SD tune question - smoking exhaust

[JimMueller]

So the typical procedure in the SD tune via wideband is to use 13.0 as a safe AFR. How long can you leave it like this while tuning without worrying about the piston rings, etc from cylinder washing?

The reason I ask is that I've had intermittent smoking from the tailpipes the last month with the SD tune loaded. I've only had the normal tune loaded for part of a day, and since it's intermittent I can't determine if it's the SD related.

Car doesn't run hot. Burns a bit of oil, but no more than in the past. When I told a friend about my idle/part throttle AFR while SD tuning, he was concerned about cylinder washout.

Thoughts?

[WS6snake-eater]

13.0 Is really not that rich. I don't think that washout would be a concern at that AFR. You did change everything back to stock after you dialed in the table right? Also what color is the smoke, black or white?

[JimMueller]

The smoke is white, and it tends to hang in the air. How about spark plugs, would that AFR foul them after 6-8 weeks of continuous SD tuning?

Even with the SD tuning in it was smoking intermittently. Now I've got a problem with the laptop not detecting the cable so I need to figure out how I'm going to get out of open loop :-/

I do notice that with my cutout capped, I idle at at least .5 richer than with the cutout open - sometimes a full point. Could it be the catalytic converters? The AFR was hovering around the upper 14's when I temporarily had the non-SD tune in it briefly, so I think the WBO2 is working correctly.

[AnotherUser]

It sounds far richer than 13:1 to me.

[WS6snake-eater]

Richer would be more of a dark colored smoke...White smoke indicates a head gasket problem. Does it have a sweet smell?

[JimMueller]

No, it's not sweet smelling. There is black soot on the bottom of my rear bumper. It's a dry soot, not greasy.

[cured5.7]

Jim,
That dry black soot would be from the vehicle running slightly rich.
The white ish smoke will most probably be moisture that has condensated
in the exhaust system ( steam ), The catalytic converter produces H20 as part of its operation as well.

Or the moisture might be coming from blown headgasket (s).

Hope this helps.

Regards Mark

[JimMueller]

But how long would it take for that condensation to disappear? Sometimes the smoke will follow the car for 15-20 minutes. Could the catalytic converter produce that much condensation under these conditions? Is it possible to have an intermittent head gasket leak?

[S2002S]

How does your oil look? If it looks weird or foamy you may have a head gasket leak.

[AnotherUser]

I still think it could be running rich. I have seen cars run rich and have white smoke.

[cured5.7]

Jim,

Whats the temp where you are?

White smoke ( steam) can hang around all day if the conditions are right.

Once a headgasket starts to leak it will mostly leak all the time. Is your coolant level dropping?. Do you have to top it up constantly?
When you first start it when its cold does the engine misfire at all and then clear up?

Have a smell of the white smoke does it smell sweetish or like your coolant in your expansion chamber

I have never seen an engine that runs rich ever produce white smoke in 16 years of being in this trade.

Regards Mark

[JimMueller]

- The ambient outdoor temp is typically 60-ish in the morning.

- When it happens, it's not just a little smoke. Sometimes when I'm stopped at a light it almost envelopes the entire car. Almost like something is on fire.

- Car doesn't misfire at startup

- I've had three different car guys/mechanics snort the fumes, and none think it is burning coolant. I've smelled a car burning coolant before ( an MTI 427). I noticed a few weeks ago that my overflow tank seemed low and I topped it off. The car doesn't run hot.

I'm back in closed loop after swapping my serial cable two days ago. It smoked a bit this morning at startup, but not since. Hopefully that was just condensation.

[AnotherUser]

I have never seen an engine that runs rich ever produce white smoke in 16 years of being in this trade.

I have seen it. But it wasn't just rich. It was pig rich.

[cured5.7]

AnotherUser,

sorry I don't want to step on any toes, I was just stating that I have never seen a vehicle that is running rich to have white smoke coming out of the exhaust but anything is possible I suppose.

Jim,

Good to see that the problem has been reduced. If you ever find out how/why that happened please post and let me know, I'm very interested to know what it was.

Regards Mark

[AnotherUser]

AnotherUser,

sorry I don't want to step on any toes, I was just stating that I have never seen a vehicle that is running rich to have white smoke coming out of the exhaust but anything is possible I suppose.

Jim,

Good to see that the problem has been reduced. If you ever find out how/why that happened please post and let me know, I'm very interested to know what it was.

Regards Mark

Oh don't worry about me. I know that it is usually black smoke. I have a thick skin like a rhino...

[BlueDragon]

I don't like being the bearer of bad news, but it sounds like you have either a cracked head (Leaking coolant into exhaust port, or a bad head gasket). I had this on a pickup truck I had. I looked like a steam jenny going down the road, ran great nothing in the oil, just clouds of steam out the exhaust. And oh yes coolant was low. Time and amount will vary depending on where the leak is or how bad the crack is.

- The ambient outdoor temp is typically 60-ish in the morning.

- When it happens, it's not just a little smoke. Sometimes when I'm stopped at a light it almost envelopes the entire car. Almost like something is on fire.

- Car doesn't misfire at startup

- I've had three different car guys/mechanics snort the fumes, and none think it is burning coolant. I've smelled a car burning coolant before ( an MTI 427). I noticed a few weeks ago that my overflow tank seemed low and I topped it off. The car doesn't run hot.

I'm back in closed loop after swapping my serial cable two days ago. It smoked a bit this morning at startup, but not since. Hopefully that was just condensation.

[cured5.7]

Oh don't worry about me. I know that it is usually black smoke. I have a thick skin like a rhino.

[JimMueller]

I checked some things last night. Even though my engine gauge never indicated I was running hot, I was low on coolant. If I had to guess, I'd say it was a good 3" below the overflow tube on the radiator cold. I added distilled water to the radiator while it was running until it seemed to settle at full.

Then I checked the overflow tube, and it was shy also, even at hot. So I added enough coolant to the tube to make it read full hot. In the morning I checked the level, and it stated full cold.

I do know that the radiator was full when I last put the heads on. I don't recall the fiull level of the overflow tank.

Engine oil was at the bottom of the hash marks. And I noticed that that driver valvecover bolt which I snapped long ago wiggled itself out of the hole.

I have noticed that my AFR is reading a range of ~13.x-15.x at idle, usually in the low 14's. I guess I should re-calibrate the sensor and put those new O2's in.

[12secSS]

You possibly have a leak in your coolant system, that is obvious. The smoke you see is in fact condensation, which is a by-product of a properly mixed fuel combustion (not that cats). I know this because with my SS, if I have the cats on during cold morning, it would have subtle amounts of condensation. After remving my cats, there is a lot of condensation emulating from my CME, so much that people think there is something wrong with my car. Also, if you richen up your mixture, it will decrease the condensation. Try it out next time you play with your car, with the cutout open and closed. You should see more cendensation with the cutoput opened if you misture is about 14.7:1, less if you are running richer. The reason why you don't see as much with the cats is because that is there function, to burn up residual by-products (H2O and CO) from the combustion chamber, this reduces emissions.