Manifold leak?

[xrobbx03]

When i rev my engine i get some black smoke where the manifold gasket is? This means its leaking correct?

 

[JayRolla]

Could be something burning on the outside like oil from a leaky gasket. If smoke is coming through a leak then you should be smoking out the tail pipe. If no smoke out the tail pipe than I wouldnt think its leaking. A leak there will give you boost problems sometimes also. You can suck a little oil through a vaccuum line on the intake mani while its running. Just a little like a cap full. The car will burn it and lots of smoke will come out the exhaust. Now look for more smoke at the mani and see if it changes when you burn the oil.

 

[SpawnedX]

Is it black or is it blue, and is it coming from intake or exhaust?

Edit:

Remember, smoke color tells you a lot about the possible problem.

Gray almost non visible smoke is normal exhaust.

Blue indicates oil is burning somewhere.

Black is a sign of high carbon, which indicates excessive fuel burned.

Puffy white indicates you are burning coolant, probably blown head gasket.

The more I think about it, the more I think you must mean the exhaust manifold and if it is truly black, you must be burning excessive fuel. Of course this is assuming it's also coming out from the exhaust. Now if it is just coming from the manifold, it might be something electrical burning?

 

[xrobbx03]

Sorry i did mean the exhaust manifold. Yes is its a black smoke and i had a friend drive behind me when i punched it and black smoke came out of the exhaust pipe as well.

 

[oldman]

There are two issues here sort of unrelated to each other.

1. Regardless of what color the smoke is, if it's coming out of the exhaust manifold, you have pre-o2 exhaust leaks which will affect your turbo operation as well as closed loop operation (idle and part throttle) due to inaccurate o2 sensor readings.

2. Black smoke = unburnt fuel = running rich. There are many causes for this, most notibly a vented BOV, boost leaks, bad o2 sensor, bad coolant temperature sensor, defective fpr or lack of afpr with an upgraded pump....etc.

 

[xrobbx03]

My new manifold just came in the other day. I am replacing that and I also have a bad leak in my flex pipe which is going to be fixed this saturday along with a high flow cat since i have been running catless and need one to pass emissions which im required to do this month

 

[xrobbx03]

There are two issues here sort of unrelated to each other.

1. Regardless of what color the smoke is, if it's coming out of the exhaust manifold, you have pre-o2 exhaust leaks which will affect your turbo operation as well as closed loop operation (idle and part throttle) due to inaccurate o2 sensor readings.

2. Black smoke = unburnt fuel = running rich. There are many causes for this, most notibly a vented BOV, boost leaks, bad o2 sensor, bad coolant temperature sensor, defective fpr or lack of afpr with an upgraded pump....etc.

so are you saying that the leak itself is not the exhaust manifold.

 

[oldman]

so are you saying that the leak itself is not the exhaust manifold.

How did you come to that conclusion from my post? Where exactly is it leaking on the manifold? The head flange or turbo flange?

 

[xrobbx03]

its leaking at the head flange

 

[oldman]

its leaking at the head flange

Then why are you replacing the manifold? The only time you replace the manifold is if there is a crack or the flange is warpped, which can not be determined without removing the manifold. This sounds more like a gasket or missing studs problem to me, at least until you pull the manifold.

BTW There is no way you will pass emissions if you can visually see black smoke, you still have to address the "running rich" problem after you fix the exhaust leaks.

 

[xrobbx03]

well i figured that if i was going to go through the trouble of taking the manifold off i would just by a new aftermarket one that comes with all gaskets and bolts. Only costed me 150 shipped.

I was hoping the cat would allow me to pass emissions. If i dont then i was going to get an SAFC and lean it out a little bit so it dont run as rich.