Please help with my boost leaks, I'm stumped

[markp]

Hey everyone, I was wondering if you guys could help me with finding and fixing my boost leaks that I am currently having. Just to be on the same page, here is the list of the following I have fixed:

intercooler couplers
vacuum lines to fpr
throttle body gaskets
throttle body seals
injector o rings and insulators

After fixing these, I went from building 0 psi to 15 psi leaking 1 psi per second until ~10 psi where it then leaks very slowly to 0.

While testing, no matter how much air i put in, I could not test above 15 psi. After soaping EVERYthing, I found no leaks and could hear nothing..until I opened my engine oil fill cap. I then took off the PCV valve from the valve cover and pressurized once again to see if any air came out and none did, although the pcv is really old (should i change it anyway?). I then listened at the tailpipe for any sounds and did not hear anything.
After reading multiple threads, I decided to do a compression test ( my first one ever) and here are my results. I did this with the engine at full operating temperature, cranking while wot.

185-185-180-185

Then I did the wet test, adding a little bit of oil down the walls and got these results:

200-185-190-205

How worn are the rings based on these results? Would this cause me to not be able to test above 15 psi? It's really bothering me, especially because I'm trying to fix this problem where my car jerks for a second if I'm cruising at constant speed and throttle position which gets worse when it's hotter out. The plugs and wires are both relatively new.
Any help is appreciated!

edit: My biggest complaint is that the car doesn't even feel that much faster after fixing those first leaks and that it's REALLY annoying when the car bucks at constant throttle. It happens maybe once every 5-10 min in summer weather, and rarely in winter weather.

 

[markp]

I also wanted to note that a few months ago, I pulled my plugs and found some oil on the threads: I was concerned that oil was leaking past the rings but no one confirmed so. http://www.dsmtuners.com/forums/newbie-forum/283506-hows-condition-my-spark-plug-pics-attatched.html

This time when I pulled the plugs however, there was not a trace of oil on any plugs. The only difference between this time and last time was that I think I pulled the plugs last time when the engine was cold and this time when it was at full operating temp. Also, the original plugs were the 6ES, and the new ones are 7ES. Anyone think this is the cause of the difference I'm seeing?

 

[cdndsm]

I'm no expert, but those compression numbers look pretty good.

Is there any oil on the valve cover? It could possibly be leaking out the oil cap down into the plugs.

As far as your bucking/hesitation. I would make sure you ignition system (plugs you mentioned, but wires etc) is in good shape before you worry about rings not sealing.

 

[markp]

There is some oil leaking from out the valve cover, but I think the valve cover gasket just needs to be changed. I see no oil going down the spark plug wells. As for ignition, what else do I check? My wires are fine and spark plugs are pretty new.

 

[webconnect]

Wow your engine looks strong as a horse with those compression #s.

 

[markp]

Wow your engine looks strong as a horse with those compression #s.

Yeah I guess but I can't find the leak into my crankcase. It's very frustrating. I pressurized the system with the PCV out and no air came out, hear nothing in tail pipe, and I'm not pushing any coolant or have any oil in the coolant. Anyone have ideas why I'm leaking into the crank case, making me not be able to test above 15psi?

 

[kenamond]

Did you boost leak test on a warm motor? That makes a huge difference just like a compression test is very different warm vs. cold.

One possible source of the leak is intake valve stem seals. They're in the "roof" of the intake ports, so they see boost pressure. If they leak, it goes up to under the VC thus leaking into the crankcase.

 

[markp]

Did you boost leak test on a warm motor? That makes a huge difference just like a compression test is very different warm vs. cold.

One possible source of the leak is intake valve stem seals. They're in the "roof" of the intake ports, so they see boost pressure. If they leak, it goes up to under the VC thus leaking into the crankcase.

Yup, I tested on both a cold and warm and it's about the same. How can I verify if it's the intake valve stem seals? also, do you have any ideas about the jerking issue I mentioned above, while at constant throttle? Would a boost leak cause that? And what do you think of my wet test, is that normal ring wear or something I should be concerned about? Thanks for your input.

 

[kenamond]

I've never done a wet test, but the guidance is that if your compression goes up more than 30psi in the wet test that your rings are too worn. The impression I get with intake valve stem seals is that if you have good compression, no PCV leaks, and no HG leaks, it's the only way for BLT air to get to the crankcase. It might be passing through the compressor seal, down the oil return tube, and into the crankcase at the oil pan, but usually, you'll hear slow bubbling during the test from very small amounts leaking that way. You can test at the TB elbow instead to rule out the compressor seal as a culprit.

I find it odd that the wet test results went up for everything but one cylinder. I don't know much about wet testing, but *no* change in compression would tell me that your rings are sealing *perfectly* on that cylinder without the oil...why that one and not the others? What I'm thinking is that the oil you added didn't get down the whole way around the crown and you didn't actually wet test that cylinder. Might want to try that one again.

As far as the stumble you're having, it's usually an ignition issue. If the plugs are good and gapped correctly, and the wires are new, move back to the "earlier" parts of the ignition system. If you're running 15psi or less, I'd recommend 6ES's gapped to 0.028". The 7s are cooler and deposits will not be burned off as well as a result. What boost are you running? I've never had any problems with ignition, and I admit I don't know any more than you do about it.

I'd recommend replacing the PCV valve. It's $8 at Mitsu. Don't get one from Autozone/Carquest/etc., as they'll leak right out of the box. The other option is to get a $1.25 plastic check valve from USPlastic and install it in the PCV-IM line to play "backup" for the PCV valve's check valve function. There is a thread called "Stupid PCV question" posted by FORMONTOYA that has the part number (and oooodles of info about PCV system and catch cans, etc.).

 

[markp]

Yeah, about the wet test, it was the first time I ever even did a compression test so for that 1 cylinder that didn't go up, I think it's because I didn't add as much oil as I did to the others. I sorta felt uneasy dumping oil in there, I'm a noob. But if I did put more oil in it, I think it would have had similar results to the other 3.

As for the jerking, I have my boost set at 16 psi, reading about 10.5 on the AFR with 560cc injectors and a 190lph fuel pump. With the 6ES plugs, my car was stuttering at higher rpms which was eliminated when I put in 7ES gapped at .028 inches. I don't know what else to check as far as ignition goes.

As for the PCV valve, I've never changed it before and it's been a few years since I've had the car. I did pressurize the system with the pcv taken out of the valve cover to see if any air came out but none did. I was just wondering if it's possible that the PCV valve was so clogged, it doesn't even open up either way, leading to increased crankcase pressure and thus messing up the valve stem seals? My car has ~60K original miles. I thought it was too soon for this type of problem to show. Thanks for your help! I do plan on getting one of those plastic check valves anyway for the future. I actually have an aftermarket pcv valve sitting next to me that I am going to return after reading that 'stupid pcv' thread haha.

 

[kenamond]

The PCV valve only flows the other way when the IM is under vaccuum, so it would only affect idle if it were completely clogged. The VC breather is where the excess crankcase pressure is relieved under load.

As for BLT, I'd go over everything again and make sure the BOV isn't leaking (pull the recirc hose and listen), BOV flange, pinholes in IC hoses/couplers, IM gasket, j-pipe gasket (if you have a down-firing turbo). Also, I find it easiest to leave the VC breather hose off when I test so I can tell how much air is coming out the crankcase.

 

[markp]

By valve cover breather, do you mean the line that goes to the intake pipe? Also, what would happen if the pcv was totally clogged, how would that affect the idle?

I guess I'll do another BLT, last time I did not check the bov itself with recirc tube off (1g bov unmodded). I didn't see any obvious leaks though. The biggest one is definitely coming from the crank case when I open the oil fill cap. It's a constant, kinda soft pshhhhhhhh... =(

Any other ways to check to confirm if it's the valve stem seals that are bad, and if it is those, any idea why they would go bad with only 60K?
I just searched and the only way I saw to see if it's the seals is to take off the exhaust mani and see if there's any oil coming out of the runners, is that the only way?

I've never done a timing belt change and am a little intimidated after reading the vfaq on changing the seals. I've only done the basics, exhaust, turbo, intercooler, fuel, gauges , accessory belts, etc. Think I can take this on? I want to hold 20 psi boost during a BLT damn it!

 

[tbonitz301]

As far as the ignition goes i would try closing your plug gap a little to see if it helps. I knoow that it's recommended that you gap them to .028, but try .024 and see what happens. This could help you troubleshoot a weak ign. system. Also check your wires on the boot for tiny burn marks where the top of the spark plug sits up in the wire. This help me greatly when i was troubleshooting my high rpm misfire. To be honest i just keep my gap at .024 now, and have no misfires.

 

[markp]

If I gap them to .024 and the problem gets better, what do I check for then?

 

[tbonitz301]

Coils,wires. To be honest i just gapped them to .024 and the misfire stopped so i never did anything else to it.

 

[markp]

Alright I'll try that and maybe try a different ignition coil pack and see if it makes a difference. If my valve stem seals are bad, would it be bad to keep driving? Will all the oil gunk up in my turbo?

Edit:
I was looking around and found this write up for BLT's:
1. Disable your mbc.
2. Turn your motor to 30* ATDC to avoid valve overlap.
3. Start your test at the TB elbow and focus on area behind the TB first.
4. Spray soapy water at TB gasket, BISS, TB shaft on both sides, IM gasket, injector insulators, brake booster, afpr and all vacuum lines/connections.
5. Open your oil cap and listen for leaks. (PCV, valve seals/guide, rings)
5. Listen to your tailpipe for leaks. (EGR, valve overlap, jumped timing, bent/unseated valves)
6. Once all leaks are fixed, move the tester back to the turbo inlet.
7. Spray down the compressor cover (known leak), BOV return/flange (DO NOT TAP YOUR BOV LINE FOR YOUR MBC!!!), IC end tank/fins and all connections. Re- test.
8. Note that you will leak air into the crankcase through the turbo seal but do not panic, this is normal during a static pressure test as long as there are no shaft play.

I have no shaft play and I was wondering exactly how much air usually leaks through the turbo seal? I also do not blow any smoke.

 

[markp]

I keep searching about valve stem seals and I keep seeing that people usually suspect them after they have a lot of smoking. I don't smoke at all, at startup or in between shifts. I was wondering if maybe it is just air going through the turbo seals? Do you guys usually hear absolutely no air in the crankcase while doing a BLT?

 

[kenamond]

I keep searching about valve stem seals and I keep seeing that people usually suspect them after they have a lot of smoking. I don't smoke at all, at startup or in between shifts. I was wondering if maybe it is just air going through the turbo seals? Do you guys usually hear absolutely no air in the crankcase while doing a BLT?

I hear a bit. But I BLT to 20psi and leak down 1psi every 3-4 seconds. The turbo oil return tube will bubble maybe once per second. My compression is around 170 across the board, so I don't know how much is ring blowby vs. intake valve stem seals vs. compressor seal, but I hold boost just fine, so I don't have to worry about it.

If you think it's turbo seals, test at the TB elbow and see if things change.

I'm still not convinced you fixed all the other leaks. Hearing a hiss from the oil cap might not be a problem. If you test at the TB elbow inlet instead of the compressor inlet and things change, there's a leak between the comrpessor and TB elbow.

 

[vancitydsm]

Do a " turbo system leak test" i just take off my intake pipe to the turbo put a silicon hose with a can of something clamped to it onto my turbo sealing in the compressor side of the turbo.. i get compressed air and shoot a bit into my system with a friend checking my gauge.. i then spray some water/soap solution around areas i hear air leaking.. That should help your leaking problem. Ensure your plugs and plug wires are not corroded at the tips.. you have plenty of compression so that should not be an issue. Also while your mass air meter is out i like to just spray a bit of intake cleaner into it just to clean out some debris. While doing the turbo system leak test MAKE SURE you have a boost gauge/vacuum gauge hooked up and slowly pressurize the system. If you put tooo much pressure in there you could easily blow something ( fuel reg, wastegate actuator ) If your strictly leaking into the crankcase on a leak down test.. i would most likely suspect the valve seals or rings. But if its not tooo much dont worry about it your permitted a bit to come out. If you want a direct number just hook up a boost/vacuum gauge to your pcv hose and block of the breather hose and see what you get. I'm not as experience as everyone on this site, but I'm an apprentice tech so i know a few things.

 

[Noogabox]

Codename: Upgrade, Xbox 360 TalonThis Jumping issue is definatly ignition related. When you have poor ignition under boost the amount of boost that your turbo produces will signifigantly reduce. You will have the RPM's go up but you will randomly have the car Jerk and rpms will drop like 500 and them come back up. This is from when your car misfires it retards timing. It causes the rpms to go up and down too when you try to hold the Accelerator at a constant point. You definantly have a ignition issue. Now that we know thats a Misfire we need to look at what is causing it for you. Misfire can be caused by a couple things. Assuming your ignition its self is fine then you either have a gap that is too large or fuel is way too rich. Note that if your air fuel gets richer your ignition requirements go up.

If you gap ALL THE WAY to .024 then you have a weak spark. The culprit can be a weak ignition coil or bad wires. It takes "X" amount of voltage to jump a gap. When the air is denser ( as in boosted) that "x" number goes up. at .035 you should be purring like a kitten at 10psi Boost. Take in mind at 14 psi Mitsu has plugs gapped out at .032. If you are all the way down to .024 at 15 psi boost you need more voltage out of your coil! You can always get a higher volt ignition. However to compensate till you get beter ignition you can have a smaller gap like that, it just does not ignite the fuel as well with a smaller spark.

I recomend the 80,000 volt On plug cap. Does a little better than the 65,000 volt Oem ( on a good day when it was new)

I personally like NGK Iridium Ix myself gapped at .035 at 10psi

Codename: Upgrade, Xbox 360 Talon

 

[markp]

Thank you everyone who gave input. I really appreciate it. I will recheck for leaks by testing at the TB elbow and see if there's a change. I'll also check my bov w/o the recirc tube on, although I did not hear anything from there when the tube was on before.
As for ignition, I will try the smaller gap, and I also recently picked up a used ignition coil pack for cheap so I'll see if a different one makes a difference. I will report back with any updates.
Thanks everyone!

 

[markp]

Alright everyone, here's an update:

I warmed up the engine , disconnected my pcv valve from the valve cover, and did another BLT to double check any intercooler pipes/couplers etc and after taking off my bov recirc tube and spraying some soapy water, I did notice it leaked very slightly @ about 15 psi.
I then retested at the throttle body elbow, and for some reason doing it this way made my pcv valve leak like crazy above 15 psi. I also noticed a very slight leak at the BISS screw.
After taking the PCV valve and line off and capping the port on the intake manifold, I retested and I may have pressurized the system either too much or it's just that I never was able to go above 15psi to notice that one of my injector's o ring or insulator started to leak =( I hate fixing the leaks here because once I fix the leak at one injector, another one starts leaking.

During all these BLT's, I had taken the breather line off the valve cover but felt no air coming out even though I heard an equal amount of air in the crankcase testing at the turbo and at throttle body elbow.

So for now, I will be working on fixing the bov, biss screw, and ordering one of those USplastic check valves for the pcv, and fixing the injector leaks. Feel free to leave any comments, thanks guys.

 

[silver bullit]

Is your motor stock, the compression numbers are good but which motor do you have, stock turbo, built, na etc need details and last i checked you have a stock 2g bov, they are plastic and cont hold shit. If you have a 1g then check the seals/gaskit, and make sure it is not leaking or the valve is opening.

After fixing these, I went from building 0 psi to 15 psi leaking 1 psi per second until ~10 psi where it then leaks very slowly to 0.

This is normal



200-185-190-205

Again i need to know what motor you have na, turbo built etc...

The bucking may be a bad ecu unlikely or maf id check the maf.

Also check all you intercooler pipes and couplers for holes, cuts, nick, dry rot, etc.

The oil coming into the motor could be cause of the way the stock oil recirc into the intake pipe, (due to the line comming of the valve cover to intake pip allowing the oil to travel into motor, unless you have a catch can).

As far as oil on spark plugs could be cause of the stock oil breather line off the valve cover or valve stem seals, piston rings (which can be cause by after market pistons not heating as fast as the rest of the motor and allowing oil to blow by etc... There are to many varibles, but answer the questions above.

The compression you have is good, but i need to know what motor you have.

 

[kenamond]

Alright everyone, here's an update:

I warmed up the engine , disconnected my pcv valve from the valve cover, and did another BLT to double check any intercooler pipes/couplers etc and after taking off my bov recirc tube and spraying some soapy water, I did notice it leaked very slightly @ about 15 psi.
I then retested at the throttle body elbow, and for some reason doing it this way made my pcv valve leak like crazy above 15 psi. I also noticed a very slight leak at the BISS screw.
After taking the PCV valve and line off and capping the port on the intake manifold, I retested and I may have pressurized the system either too much or it's just that I never was able to go above 15psi to notice that one of my injector's o ring or insulator started to leak =( I hate fixing the leaks here because once I fix the leak at one injector, another one starts leaking.

During all these BLT's, I had taken the breather line off the valve cover but felt no air coming out even though I heard an equal amount of air in the crankcase testing at the turbo and at throttle body elbow.

So for now, I will be working on fixing the bov, biss screw, and ordering one of those USplastic check valves for the pcv, and fixing the injector leaks. Feel free to leave any comments, thanks guys.

It's almost as easy to change all 4 injector seals as it is to do 1. If one is leaking, the others are most likely bad/hardened. I pulled the fuel supply hose and FPR off the rail so I could get the rail all the way off, but when you pull the first of those off, have a rag wrapped around the connection or you'll maybe get a face full of gas. Follow the tech article on removing the fuel rail. It's 7 bolts I think (two on each end, three holding it to the head). Don't lose the plastic spacers where it bolts to the head. Depressurize the fuel system by unplugging the FP connector (under the back seat), opening the gas cap, and running the car until it stalls. It'll still contain some pressure (mine did). If you have compressed air, blow dust/bugs/leaves out from around the base of the injectors (at the head) or use a brush or something to get most of the crap out of there so it doesn't fall into the intake ports. After you're done, you'll say, "That wasn't hard."

For the BISS o-ring, carefully tighten it all the way and count the number of turns and write it down. You'll need to know that when you reinstall it with a new o-ring. Then unscrew it until the threads are out and do a BLT-like test to pop the BISS out of the TB (make sure you have a way of catching the BISS as it pops out). You might be able to get it out with needlenose pliers or something, but the o-ring keeps it pretty snug. A #5 o-ring from the hardware store will work as an o-ring replacement. Reinstall with a bit of lube on the o-ring, tighten gently all the way, then loosen the number of turns you measured before you removed it (to get it back to where it was).

I'd go ahead and pick up an OEM PCV valve for $8 before you tear into the car (unless you have a backup car). Then you don't have to wait for the check valve.

Was your BOV leaking internally (i.e. you removed the recirc hose and detected a leak inside the BOV)? Or was it from the connection to the UICP?

 

[markp]

My bov was leaking internally which I noticed after I took the recirc tube off. I sprayed some soapy water inside the "discharge" part of the bov and when I pressurized it, I could see very slight bubbling.
As far as the fuel injectors, the insulators and O rings are actually relatively new. I changed out the 450s to 560s maybe 6months to a year ago. When I did this, I did not disconnect the fuel line or fpr, barely giving me enough room. I guess that's why I hated doing it. I was wondering if I were to just disconnected the fuel line from the rail, would I need to get a new gasket or will it seal just as well when I reconnect it.

What do you think of the air in the crankcase? It sounds exactly the same in terms of no bubbling, and also about the same amouunt of air. I also feel nothing coming out the breather nipple. Can this nipple ever be clogged? I didn't feel anything when i put something small through it.
I have a backup car so I'm just going to wait for the check valve. Is it okay to use with a bad pcv valve?