Generally speaking if oil is getting out, then air is getting in which can cause a lean condition.

 

Thanks Mac,

Even from the oil pan? Wouldn't that mean my piston rings are potentially due for a replacement if air is coming through? I will say, even though it looks like it leaks pretty bad, it doesn't loose much oil overtime.

 

Hi @mmoreno , sorry it's been awhile. Did you also replace the individual intake-runner gaskets when you had it apart? I can't remember if you did it previously, but those tend to cause the car to be really lean when cold, then somehow they expand when they warm up causing the STFTs go back down toward zero.

-j

 

No worries J,

Unfortunately I did not do that... sounds like I might have to get that intake manifold off again at some point then. Would they show a leak through a smoke test fairly easily?

 

It could, but it may be difficult to see exactly where it’s coming from. I used unlit butane and aimed it directly at each runner and found that cylinder 7 was leaking when cold. If you use the unlit-gas method, make sure to move really slowly and look for a decrease in STFT on whichever bank you are testing at the time. Good luck!

 

Another question if I may,

As I wait for the right time to do a smoke test when cold, I was tinkering with the OBD II in the morning and noticed that the engine switches pretty quickly to Closed Loop. Shouldn't the engine switch to CL once its warmed up? I'm not sure if these cars have a built in O2 sensor heater or something like that.

 

Further clarifying my previous response,

To be precise, it switches to Close Loop at 55°F with O2 reading high while cold. I would be inclined to assume this is not normal behavior per se, but I would like to know what are the thoughts on that?

 

These cars do have heated O2 sensors, and they switch to closed loop as quickly as 30 seconds if I recall correctly.

With the symptoms you described, I think it is more likely that thermal expansion is "sealing" a leak somewhere. When you do the smoke test, make sure the engine is stone cold.

 

Little update to this post. I know its been a while, but finally got a decent smoke test done. We added the smoke from the back of the intake elbow, there is a hole that connects to the some sort of solenoid into the fuel rail (evap?).


1. Found that the rubber gaskets on the upper intake manifold where leaking. So, I'll have to take the intake manifold off again (we will be replacing the back rubber gasket and the metal ones again to be safe).

2. Top of the EGR solenoid leaks too. We went ahead a put a little bit of high temp seal between the plastic and the metal part (waiting for it to set as I type this).

3. PCV leaky O-ring. Went with a thicker one and that fixed that.

4. Throttle body leak by the spring. We tried opening the butterfly valve to see if it changed anything, to no avail. I assume the fix for that is a new throttle? I would imagine there could be a way to replace the rubber ring that seems to be there, but I assume its not recommended to do so on your own.

In hindsight, we should have done the rubber gaskets, metal gaskets and the valley hose in one go. At that time I just needed the car to drive so we did what we needed for it to work. I know people suggest replacing the knock sensors, but they haven't been a problem so far.

I'll update this with more results as I go. Thanks again to everyone for your advice and knowledge.

 

Update (Solved)

After some good work on the intake manifold gaskets and the 8 rubber penlum gaskets, codes went away and no crazy rought idle when cold. CEL is also gone for good. I did not change anything with the throttle nor the EGR. Fuel trims are higher on bank 1(+5LTFT compared to +3LTFT on Bank 2) but nothing concerning in my opinion. Did a transmission fluid change on it and it drives silky smooth. Lesson here is, CHANGE AS MUCH AS YOU CAN IN ONE GO. We could have solved the leaks many months ago and saved some good money on gaskets. Oh well, its fixed now.

Thanks everyone for the advice! Much appreciated.