Engine Codes

[RichRich]

I have my PCV line completely disconnected at the moment and it still runs completely normal, when I thought I was maybe having mass airflow issues I just completely disconnect the sensor and it will run on its default settings so should run with full power. You have that vacuum line hooked up near the MAP sensor right? That will disable all boost

 

[Briann1177]

You're talking about the vacuum line that hooks up next to the IAT2 sensor on the throttle body tube? Yes, that line is hooked up.

 

[Waterdriver]

For the PCV, it should flow/suck air from the valve cover and into the intake.
You do not want to pressurize the crankcase. You will blow oil and seals out of your engine under boost.

 

[Briann1177]

The PCV line hooks up to a non-pressurized portion of the intake right by the air filter. It's way before the turbo.

 

[ctuinstra]

For the PCV, it should flow/suck air from the valve cover and into the intake.
You do not want to pressurize the crankcase. You will blow oil and seals out of your engine under boost.

I agree with this. The whole point of having a PVC is to vent the crankcase. In the past it was vented to the atmosphere. Now because of emissions, they vent it into the intake to burn the pollutants. If you have excessive amount of venting, it's a sign of cylinder blow-by.

 

[ctuinstra]

If you want to test, you could disconnect the PVC from the intake and block off the intake connection. Vent the valve cover to the open air. Now if the LNJ does have a PCV valve inside the valve cover, this could still be in the way if it's blocked and not venting.

Point being, I don't believe you HAVE to vent the crankcase to the intake in order for everything to work. But if you do and there is something wrong such as a leak, it can cause issues.

 

[Briann1177]

That's what I thought too. Then I got to looking at my old plastic intake tubes and turbo inlet fits, and there's not a drop of oil on them. This sounds weird, but they don't have a blow-by smell on them either. Everything is spotless. I know my engine is pretty low mileage at 48k, but there should still be some kind of blow by.

 

[SliderR1]

I agree with this. The whole point of having a PVC is to vent the crankcase. In the past it was vented to the atmosphere. Now because of emissions, they vent it into the intake to burn the pollutants. If you have excessive amount of venting, it's a sign of cylinder blow-by.

This is true - just need to make note of how each of these systems work. They don't operate like a typical PCV system in that there is internal passageways cast into the cylinder block, head and intake manifold. On the LSJ, when the internal check valve is under vacuum, the PCV system is pulling air INTO the valve cover from the air intake - that is why the system connects post MAF. The system uses this to supply fresh air that ultimately ends up in the intake tract and since its post-MAF, it is METERED air into the engine. If you just have a filter on your valve cover you are introducing unmetered air into the combustion chamber (albeit a very small amount most likely) when the system is not under boost. This could potentially cause idle issues.

I think the LNF systems operate under a constant vacuum, even when in boost, based on the way the system is designed. There are some decent posts by Powell on the subject on CSS forum about it - just have to weed through all the garbage...

 

[Briann1177]

Here's a diagram that I found from the Chilton Library. It show the flow going from intake to valve cover. There also looks to be something cast into the mating surface of the intake manifold where the blow by gases go an enter the combustion chamber. This also explains why my intake manifold runners were coated in oil when I took it off to clean my valves.

 

[Briann1177]

No dice. I took Chads advice and plugged the PCV line with a bolt and left the port on the valve cover open. Code kicked back in two miles down the road with no boost.

I'm officially out of ideas. I have no other ideas other than taking it to a dealership where they will probably be of no help.

Very, very frustrating.

 

[Adam]

Can you take photos of the turbocharger, intake/charge pipes, vacuum hoses, intercooler, MAF tube and air filter so that we can see if anything looks out of place compared to the turbo car we have here?

Have you bolted your intercooler in place over the intake? I have no clue why, but the tapped holes in the air to water intercooler go all the way through and will leak if you do not install bolts (preferably with some thread locker). This could act similar to a crack in an air to air intercooler.

 

[Briann1177]

Yes, intercooler is bolted down with thread locker. I was paranoid about air leaks with the straight threads.

 

[Waterdriver]

Dont know if you already found this and checked but could be something to check.
"Well guess what. I found that the silver cover on the MAF sensor is tied to the output pins on the MAF. If it touches anything metal on the cover it will see low resistance ground (if your tube is mounted to metal) on some of those pins and skew the MAF pitching out a P0101 and the fuel curves will be erratic as hell because the MAF frequency is all jacked" from cobalts forum.

 

[Waterdriver]

Also this to check: "In the end, the pigtail to the Maf had separated internally where it was giving it a bad reading. Sometimes the car ran good other times not. Thats what fixed my problem." CobaltSS forum.

 

[Briann1177]

I'm going to see about picking up a new MAF sensor tomorrow. It's probably a waste of money, but I guess it's worth a shot. I don't remember if the dealer just cleaned it or actually replaced it when I took the donor in last year. I did have a big gaping crack in the original charge air cooler necks, but maybe it's possible the MAF sensor was the main issue all along and maybe they just blamed the code on the crack when they found it. I really don't know.

What's odd is I never had a problem driving the Goblin the very first 30-40 miles over several ignition cycles. Now when I clear the code I can barely go two miles before it comes back and the boost turns off.

 

[SliderR1]

have you checked all of the MAF wires for continuity back to the ECM?

 

[Briann1177]

Just checked the wiring, and it looks good. The sensor seems to be responding to air flow changes. When I monitor the air flow in Torque, the numbers seem to change accordingly with the throttle pedal. Blowing on it makes the numbers fluctuate too. On the surface of my testing, everything appears to be good with it. However, I really can't look much deeper because I don't have the tools.

I don't get it. Still waiting to hear Adam's thoughts after posting the pictures. I'll see what a new sensor will do, but I'm not holding my breath because the current one appears to be brand new. At least as far as I can tell by looking at it.

 

[George]

I you had a smoke machine you could put smoke in the intake and look for an air leak?

Brad

 

[SliderR1]

Have you checked the MAP sensor wires for continuity back to the ECM? I think these two work in tandem.

 

[Briann1177]

I you had a smoke machine you could put smoke in the intake and look for an air leak?

Brad

I do have a smoke machine. Well sort of. It's a teenager with a vape.

And Slider, I have not checked the MAP sensor wires for continuity. The Torque app does have a manifold pressure output, and it did appear that the field had a value when I glanced at it this morning. I think it read about 14.1 PSI at idle? Not sure if that's correct or not.

As far as the TMAP sensor on my throttle body tube, I'm assuming it works because I'm getting accurate IAT2 temps and my boost readings on both my Aeroforce and stock gauge match and look to be accurate.

I will, however, go back and check all the continuity when I get home this afternoon.