Cold start w/sweet smell, white smoke, rough idle (Problem?)

K-Roll302 · Oct 12, 2017

Recently, I noticed on cold starts in the morning or after the car has sat for a long period of time, the idle is a bit rough for a few seconds, and there's a sweet smell like maple syrup coming from the exhaust with a decent amount of white vapor/smoke that goes away after the idle smooths out and I drive the car about a block's worth of distance. I've just crossed 19,000 miles.

A quick internet search for "sweet smell from exhaust" points to coolant/antifreeze being burnt in the combustion chamber, obviously bad. There's been no increase in engine/cylinder head temperature on the gauges. And, even though there hasn't been a decrease in performance and the car drives fine to me, I am concerned. Has anyone had this issue before? A trip to the dealership is in order for me first thing in the morning.

I hope it's nothing too serious that can't be taken care of. Staying positive.

boardkat · Oct 12, 2017

blown head gasket.

trippleyelo · Oct 12, 2017

boardkat said:
blown head gasket.

Maybe .. tuned or stock

Cold start auto choke is in rich fueling and condensation with more air vapor
Keep eye on oil for above just Winter coming on.. I get it to but I'm feed.

:shrug:

Ebm · Oct 12, 2017

.

K-Roll302 said:
Recently, I noticed on cold starts in the morning or after the car has sat for a long period of time, the idle is a bit rough for a few seconds, and there's a sweet smell like maple syrup coming from the exhaust with a decent amount of white vapor/smoke that goes away after the idle smooths out and I drive the car about a block's worth of distance. I've just crossed 19,000 miles.

A quick internet search for "sweet smell from exhaust" points to coolant/antifreeze being burnt in the combustion chamber, obviously bad. There's been no increase in engine/cylinder head temperature on the gauges. And, even though there hasn't been a decrease in performance and the car drives fine to me, I am concerned. Has anyone had this issue before? A trip to the dealership is in order for me first thing in the morning.

I hope it's nothing too serious that can't be taken care of. Staying positive.

I wouldn't panic yet. Just keep an eye on the situation. Watch your coolant and oil levels. If you see your coolant look like a milkshake(changing color too), then you should be worried. Our cars do smoke at idle when cold. That's not abnormal.

jacknifetoaswan · Oct 12, 2017

Ford engines are known to pool a little oil in the combustion chambers, due to oil leaking down around seals in the engine (at least, the 3V Modular was). I wouldn't doubt this is a 'feature' designed to save engine wear on cold startup.

Still, have the dealer check it. It doesn't cost you anything, other than time.

JR

PewterCam · Oct 12, 2017

Check the coolant level. If its low and keeps going lower its a blown head gasket. hearing that Focus RS cars are doing the same. After a while they will develop a miss at cold start, clear up and blow loads of steam like this..

[ame]

K-Roll302 · Oct 12, 2017

I am tuned and have been since it was broken in. It has been getting colder here and I initially assumed that was the cause of the unusual cold starts, but it didn't do this last year and my tune hasn't changed that significantly.

As for the video, my idle is a bit lumpy like that RS, but it doesn't smoke nearly as much as that. It's not making clouds of smoke like that, more like there's just a good deal of moisture in the exhaust.

mustang1 · Oct 12, 2017

coolant level changed at all ?

K-Roll302 · Oct 12, 2017

It has. It's below minimum and it looks darker than orange as a bit murky...

Just filled it to minimum with the Coolant I had left from my thermostat change last year.

mustang1 · Oct 12, 2017

sounds like it needs to go to shop. If too much coolant collects in cylinder, it can cause a lock and damage a piston.

Juben · Oct 12, 2017

It sounds like a head gasket. I'd do a leak down or compression test. That'll tell you for sure if it's the head gasket and even indicate where it's blown.

K-Roll302 · Oct 12, 2017

The engine tech at the dealership won't be back until Monday... And I need the car for class and work this weekend. I gonna be driving as little and lightly we possible. Staying as far out of boost as best as I can and tuning back to stock.

I realized that the reason my car isn't running hot like a car with a bad head gasket should is that my lower temp thermostat is helping it stay cool as well.

K-Roll302 · Oct 12, 2017

I've checked my oil on the dipstick and oil cap, and there's no sign of milkshake. This is strange.

matteos · Oct 12, 2017

Sweet smell is coolant.

My Thunderbird had a sweet smell for a while... Then a massive cloud of grey smoke and a blown head gasket.

mustang1 · Oct 12, 2017

K-Roll302 said:
The engine tech at the dealership won't be back until Monday... And I need the car for class and work this weekend. I gonna be driving as little and lightly we possible. Staying as far out of boost as best as I can and tuning back to stock.

I realized that the reason my car isn't running hot like a car with a bad head gasket should is that my lower temp thermostat is helping it stay cool as well.

If there is a coolant leak, coolant can pool in a cylinder and damage a piston at cold start. Best to get it looked at asap.

Cold start w/sweet smell, white smoke, rough idle (Problem?)

K-Roll302

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boardkat

CAMtard

trippleyelo

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Ebm

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jacknifetoaswan

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PewterCam

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K-Roll302

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mustang1

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K-Roll302

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mustang1

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Juben

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K-Roll302

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K-Roll302

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matteos

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mustang1

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