SEA996TT

I've used some of the forums on here to get this far. I'm a new-ish 2001 996TT owner, but the car won't pass emissions because of the CEL being on. There are two codes, both point to running full rich on all 4 cylinders....high idle. Engine runs great and idles steady around 1000 rpm.

I created a 3.5" PVC compressed air adapter and connected it to the intake after removing the airbox. Pushed air into it but would not pressurize at all, I'm assuming that it was going through open valves?

I put the airbox back in, started it and removed the MAF sensor...it ran like crap. Put it back in, ran great. I believe that means the MAF sensor is good.

I took the oil cap off, idle did not change at all. Put my hand over the open oil filler cap but nothing changed. Engine ran just fine. I could feel possibly a slight positive pressure coming out but so slight it was hard to tell. I could hear a squeal, but it seemed to come from somewhere on the right side of the engine and I believe the air/oil separator is on the left. Really difficult to know where it was coming from.

I tried spraying soapy water on some vacuum lines with my new pressure adapter, nothing. Everything actually looks like it is in good shape.

So, what now? What would be squealing (sounds like an air squeal)? How can I figure out where it is coming from? Does it sound like a crankshaft vacuum leak and not an intake vacuum leak?

Thanks for any advice, these forums have been a lot of help getting me this far!

Kevin

So you pressurized the intake with a large air compressor.. I ask because I had a person spend 1 hour trying to pump up the intake with a bicycle pump.. A large air compressor will be able to pressurize the intake UNLESS you have a leak. This includes, the "F" tube, intercoolers, turbo air inlet piping and "Y" pipe connections.

You removed the entire MAF sensor as it's missing out of the filter box?

Post your CEL codes.. The engine should not be running at 1000 rpms. Stock warm idle is 740...

This engine does not have a air/oil separator.

SEA996TT

The codes are not displaying now, so I can't remember exactly but I believe it was P1124/P1126 and P0507??

I reset the codes a few miles ago.

My air compressor attaches to a 3" plug (3.5" OD) which I put into the 3.5" intake after the MAF sensor after removing the entire airbox (MAF sensor included). I have a pressure regulator on it with a pressure sensor... Air sounds going through the pipe but no pressurization. If I take the kit out and hold my hand over the end, pressure reads on guage. Could it be going through valves or should it pressurize every time?

Thanks!!!

SEA996TT

...another note. I read somewhere about white smoke on cold start-up being a clue to a vacuum leak, and it does do that. Medium amount of white smoke at startup, does it for a few minutes. Smoke seems like condensation more than burnt oil and does not smell like burnt oil, just exhaust. Goes away when warm.

Macster

Can't help much with the leak diagnosis but I can tell you in the right climatic conditions these engines can emit a considerable amount of water vapor as they idle and warm up from cold. In some cases this can continue for some minutes.

One thing to note about water vapor vs. oil smoke is water vapor dissipates very quickly even in still air while oil smoke hangs together even as a good breeze wafts it away from the car.

SEA996TT

Thanks...I would guess water vapor. It was cold out, didn't smell and did go away but only after a while.

I read somewhere if there is a crankcase vacuum leak that it will create white exhaust, so I wasn't sure if that helped. Appreciate the info, looking forward to passing emissions after this is over!

SEA996TT

After running the engine and letting it cool down I reconnected my pressure gauge tool. Pushing air through it and still does not pressurize. I can hear air going in but don't hear where it comes out.

Is that completely abnormal or chance of it going through the crank case or valves then through the exhaust? What about throttle body?

SEA996TT

Macster

I'm not well versed in checking the Turbo engine for intake leaks.

However, the general procedure is to apply air pressure -- not too much -- via the intake and then listen for air escaping either from an intake system/manifold/hose leak, or possibly through open (or leaking) exhaust valves by checking for escaping air at the exhaust. Or possibly the air is escaping into the engine crankcase. This is checked by removing the oil tank cap and checking for escaping air.

Macster

The Turbo engine does not have the same AOS as the N/A engine and as such is not nearly as at risk of creating oil smoke due to some air/oil separator problem the N/A engines with the infamous AOS are known for.

The Turbo engine can smoke upon start up though my experience is this is rare.

However, an engine over filled with oil, filled with the wrong oil, or filled with oil that is past its change by date, or if the engine is not given sufficient idle time before shutting off, any/all of these can increase the odds the engine will smoke at its next cold start.

If the engine is generating oil smoke at startup and none of the things that increase the odds of the engine smoking at startup are present then the source of the oil that is causing the smoking at start up has to be investigated. Well maybe. It depends upon how bad this smoking is and if it is accompanied by any other symptoms/untoward engine behavior.

One possible source of the oil that contributes to the engine smoking is the turbo oil seals are going bad. If there is some accumulation of oil in the intercoolers or the turbo's compressor wheel is wet with oil these are signs the turbo seals are perhaps leaking.

SEA996TT

Thanks for the info. I suspect that it is just water vapor, not oil smoke. It is quite a bit but only when it is really cold and in the Northwest we have a lot of water in the air! Oil smoke would smell differently too.

I'm not sure why it won't pressurize at all, can't see or gear anything coming out. I'll try dropping the engine a bit for a better view, try your suggestion with the oil cap and if still nothing, find a smoke machine to borrow.

Macster

Just returned from 3+ weeks back in the (most of the time) frigid mid-west with my Turbo and I got a renewed appreciation of just how much water vapor one of these engines can generate under the right climatic conditions.

If the intake system won't pressurize you have to suspect an operator error. You need to be sure you are pressurizing the system properly.

Once you are confident you are not the problem, then you have to suspect your pressure test has managed to pop off what was initially a loose/leaking intake hose and now the hose is completely off and there is a big leak. If the leak is big enough you might not hear air rushing out.

You should consider walking the intake system with a bright flashlight and checking for any obvious hose/connection disconnects.

I believe also it is possible one piston could be at a place in its stroke both the intake and exhaust valves are open. This can let air pressure from the intake flow the opened intake valves through the combustion chamber and out the opened exhaust valves and out the exhaust.

Thus you have to either plug the exhaust system or be prepared to have a helper listen/check for air coming out one of the exhaust outlets.

SEA996TT

Got it. I'll lower the engine and walk each vacuum line that I can find. I assume that it will be difficult to see back in there with a lot of lines.

I'll try using my Halloween fog machine to see if I'm pushing air out the exhaust too. Decorative and useful machine.

I've tried pressurizing twice after running the engine so I assume that the chances of getting an open valve both times is low but the fog may help.

I've confirmed that my pressure tool works by putting my hand over the end before installed and after it is installed in the intake I don't feel any air coming out even when full open. Air is going in, has to be coming out somewhere.

SEA996TT

Fog machine works...sorta. I used a 1.5" poly tube to blow smoke into my intake. I then plugged it with my pressure test tool and pumped about 15 psi through it. The smoke is limited but I found that it was leaking from behind the y-tube that comes from the turbos, just aft of the throttle body...I believe anyway. There are two hose claps on a short piece of tube connecting the two and the one further up front was totally loose.

After tightening I tried it again but still no pressurization. Do see small amounts of smoke coming from something on the left side towards the front. I found a vacuum diagram but not sure what is up there on the left side. Will drop the engine a bit next time to get a better look. Smoke is the only way...

Haven't run it yet but I'm curious to feel how much more it will pull without pushing air out that Y tube.

SEA996TT