Crank case pressure

[90EclipsePos]

So I have been working on this car for a long time. I've always had an issue with getting it to idle right. It does pretty good but not a 100% I'm trying to figure out why my low fuel trim will constantly set to 139%. So while doing a boost leak I've noticed I lose most of the pressure from the valve cover breather. Now I've read a lot of threads on this but never really find any fixes or answers that are consistent. So when I do a boost leak test from throttle body it holds pressure. If I do it from the turbo that's when I get the blow by. So is it a seal on the turbo leaking in thru the oil. I have not done a compression test yet or a leak down those are my next steps. The engine has been rebuilt with in a 1000 miles. So I would hate to think my rings are bad. Any suggestions I can try are greatly appreciated.

 

[Biddy420]

I would plan on doing the compression test that is the most likely culprit it's is possible for a bad turbo seal to push pressure into the case but the rings are normally the one to blame

 

[pauleyman]

Elaborate "from the turbo" and " from the throttle body" What Exactly did you do? You also must figure out what's going on with fuel trim.

I would also question your custom chip and maf translator.

 

[90EclipsePos]

So I pressurized the piping heading to the intake manifold. Which holds pressure with no leaks. But when I pressurized from the air intake on the turbo the pressure leaks out the valve cover. As far as the chip and maf-t I'm not sure what I should be looking for. I set the maf-t to stock settings as I was told would be what I should set it to with the dsm chip already being programmed for the larger injectors. My exhaust smells rich but always shows lean on my fuel trim. I've tried adjusting fuel with the maf-t but never richens up and gets to the point the car starts to stumble.

 

[pauleyman]

remove sources of pressure back to the crank case. PCV, extra vac lines etc. Get the intake by itself and pressurize.
YOu must also pressurize the BOV intake or the BOV will open

 

[90EclipsePos]

I already have all the emissions and vacuum lines removed that I possibly can. When I do the test I block the line going to the boost controller. The BOV is after market and isn't leaking. As far as the PCV I have one of the us plastic check valve which isn't leaking by. I pulled it off the other day and tried blowing air thru with air nozzle and no leaks back in to the valve cover.


On a different note in regards to the fuel trim. On MMCD on knock should only read between 0 and 43 correct? What would cause it to read 224?

 

[90EclipsePos]

So I just finished a compression test and all cylinders were 170 psi. Should I still do a leak down test? Or is there something else I should be checking?

 

[90EclipsePos]

Is there any way air could be leaking past a seal on the turbo?

 

[90EclipsePos]

So started doing a leak down test. I only did cylinder 1 and 4. 1 came out pretty good but 4 I'm getting air leaking out intake and exhaust. So my next question is how can I tell if it's the valve seals or bent valves? Hopefully tomorrow I will try cylinders 2 and 3. Also just wanted to check are cylinders 1 and 4 then 2 and 3 on compression stroke at the same time. Also is it possible for compression test to show fine if both my intake and exhaust valves are leaking?

 

[iceguru1114]

So started doing a leak down test. I only did cylinder 1 and 4. 1 came out pretty good but 4 I'm getting air leaking out intake and exhaust. So my next question is how can I tell if it's the valve seals or bent valves? Hopefully tomorrow I will try cylinders 2 and 3. Also just wanted to check are cylinders 1 and 4 then 2 and 3 on compression stroke at the same time. Also is it possible for compression test to show fine if both my intake and exhaust valves are leaking?

It's possible your cam may have settled in a position that left both valves partially open, however, valves that aren't seating properly does help explain some of the stumbling and idling issues you are describing. Are you sure you were at TDC compression during your leakdown test?

 

[90EclipsePos]

I put a tissue above the cylinder and watched for it to blow off so I would know I was on compression inserted an extension till it started to get to the top and also matched up marks on cam gears.

So I was an idiot and that cylinder was not on compressing stroke. So retested all cylinders and all check out. Which is good news except. I still can't figure out why I'm getting so much crankcase pressure, or why my car is very lean at idle I'm talking between 17 to 19:1

 

[AWD-Tony]

So I pressurized the piping heading to the intake manifold. Which holds pressure with no leaks. But when I pressurized from the air intake on the turbo the pressure leaks out the valve cover. As far as the chip and maf-t I'm not sure what I should be looking for. I set the maf-t to stock settings as I was told would be what I should set it to with the dsm chip already being programmed for the larger injectors. My exhaust smells rich but always shows lean on my fuel trim. I've tried adjusting fuel with the maf-t but never richens up and gets to the point the car starts to stumble.

Check your Pcv. From what I've read they all leak especially aftermarket pcv valves. I was also having air coming from breather when I did BLT and the dipstick would always pop off after I drove it. I installed a check valve and now it doesn't leak from the breather. I also don't hear air when I do BLT which at first I didn't know if it was normal or not.

***SORRY I DIDN'T SEE YOU ALREADY HAVE ONE***

 

[90EclipsePos]

Yes I have had my share of bad pcv. So now I run a pc I have tested and works plus one of the plastic check valves. I've come to the conclusion I need larger vent lines due to being stroked and running high boost. I've checked compression and leak down and boost leak all are perfect. So will be switching to a catch can setup soon.