Smoking on start up.

So, I have an issue I have been working through that is really annoying. Only when I start the car or on blip of the throttle from idle it will put some smoke out the pipes. Once the car is running it is right on the money as far as the MTF and fuel trims are concerned. The car runs very well and have no issues other than this rich start and blips.

It started after I was redoing the MTF after installing 60lb SD's. I have tried reloading the value file for FRPP 60's and SD 60's but the car seems to like the FRPP values better. No difference in the smoke. Took a lot of fuel out on the MTF, no change. Car idles perfectly at 14.6-14.8 with trims near 1.0.

I still have a set of FRPP LU47's I could swap back in and see if there is a large difference.

I am starting to think it might be burning oil but it is so consistent and doesn't smell like burnt oil. The car runs great and will idle for days and not smoke but only on startup and short hard blips I can smell something and see some smoke. While in full boost it doesn't smoke but I have had people tell me that they can smell a bit of burnt oil. Which with a turbo car is not completely uncommon, at least that is my thinking. The heads are ford racing CNC heads and only have maybe 6,000 miles on them I can't imagine the valve seals are bad???

Build: 2009 Mustang
MMR Built 4.6 3v
Comp 6765 T4
FRPP Ported Heads
stock cams
stock VCT
Walbro 400lph
12v wired fuel pump
SD 60's

It seems you have a turbo, so it could be turbo oil seals. Check the compressor of the turbo and look for excessive oil.....some oil is ok. Do you have a turbo timmer?

But only on the startup seems that it would be coming from the engine. Not enough time to get the turbo got enough to burn the oil? No timer I just let it run for a bit before I turn it off. I will check though.

The turbo only has maybe 1500 miles on it ranging from 9psi to 16psi.

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What color is the smoke? Is it blueish, black, or white? If it's NOT the turbo then it's your valve seals. It's still possible it's the turbo though IMO. Do you have the PCV intact, breathers, or a catch can?

I have a catch can on the driver side and venting the other side. I tried to vent both and it smokes worse.



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You need to hook the other side up to the PCV system too. You're letting in unmetered air by having it half vented.

Ok. What is the difference of it venting both sides or only one side. I know this is a long conversation but not quite seeing the reasoning.

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The PCV sucks air in from the passenger side, circulates it through the crank case, then spits the now dirty air into the intake for burning. By leaving only the passenger side open, you'll be sucking in unmetered air on the passenger side and dumping it into the intake manifold. If you vent both sides and cap the intake manifold, no unmetered air will make it into the system. Either full open, or full close. No in-between.

Oh damn... I never thought of it that way. Shit could that cause some serious problems if left that way?

I just noticed that as soon as I capped off the manifold and ran them both open the car would slightly smoke at idle so I stopped and put it back. I guess I am doing nothing but throwing shitty air into the intake manifold and cylinders. Shit. FML. It is all setting in now.... the fact that I am boosting the engine and that is open to the breather it force boost in reverse order thru the engine. I feel like a complete idiot.... I was basically bleeding boost off thru the crankcase.

I just realized what I have been doing.... Pressurizing the crankcase during boost. Damn I hope I didn't ruin anything.

money is on valve seals

I might have to take my intake manifold off and clean it. It probably has oil all sprayed into it. It is probably dumping oil into the cylinders.

So, I think I solved the problem. I went and picked up some k&n breathers and put those on both sides. Adjusted some tune because it was off in some places and ran it around for a little while seems as it is not burning any oil and the car I think it is burning off crap that was built up in the cylinders and seems to be running a bit better under when under boost. I guess some more time will tell if it fixed the problem. Fingers crossed it did not cause any damage to any seals of anything else for that matter. Appreciate the help!!

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The people following you are smelling an engine under boost running rich.

You had a line going to the boost side of your throttle body, from the driver's valve cover? As long as the passenger side was open not much pressure could build up.

Should run fine now with an open crankcase and no PCV system.

Yeah the line was hooked up to the manifold after the throttle body. The car is definitely running a lot better.

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I also picked up a CFM oil cap filter so the engine will be very well vented. I kinda thought it was odd that it was pushing oil up into the filter on the passenger side vent filter. Total bonehead move. Either way it is much better and more responsive and it will be much easier to finish up the tuning now that the fueling will be accurate to what is actually going into the cylinders.

Glad to hear the problem is gone!

Bullitt6301 said:

I also picked up a CFM oil cap filter so the engine will be very well vented. I kinda thought it was odd that it was pushing oil up into the filter on the passenger side vent filter. Total bonehead move. Either way it is much better and more responsive and it will be much easier to finish up the tuning now that the fueling will be accurate to what is actually going into the cylinders.

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If you want to get more ventilation you should cut out the PCV valve on the driver's side can cover. I always ran breathers on both sides and an oil cap breather, but the driver's side one just sits there because it no longer has engine vacuum to open up the valve. When I bought my laser etched can covers I used a Dremel and yanked that bitch outta there so it could actually vent.

I will have to take a look at doing that mod.

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