madkaw Posted June 15, 2009 Share Posted June 15, 2009 I started a thread about oil on my spark plugs , but I didn't get much response. The oil was primarily wet on the threads of the plugs, but i didn't believe the engine was burning that much oil since it doesn't smoke-period. (81zxt automatic,91k miiles) So today I was doing more searching for reasons for a bad idle problem and I wanted to look at the turbo so I took off the boot for the AFM. What I found was a boot with no defects except that it a lot of oil in it from the breather line aft. So from the vent line of the valve cover back towards the turbo was wet oil. Well I decided to take off the PCV valve and look at it, but the J pipe is kind of in the way so I decided to take it off too. What I found was that the connection pipe from the Jpipe and the compressor was not even tight. In fact the clamp closest to the turbo was just kind of slid on there-that can't be good. The other clamp was barely snug. So what effects do you think that caused to the engine running? I also found plent of oil in the Jpipe all the way up into the throttle body. I was previously concerned the turbo was bad a spewing oil into the system, but I think it is being sucked out of my valve cover. What would cause that? The pcv valve seemed okay as far as working like a one way valve, but I am going to replace it anyway. Would that loose connection at the turbo cause a vacuum issue? I also grabbed the compressor wheel and it definitely had side play in it, but it didn't make any noise and the car performed decent for all its problems. I figure I had to be loosing some power with that loose connection at the turbo. I don't know if I can afford to buy a turbo right now, so what would be the worse scenerio if it decided to let go? I know I am asking a lot of questions here, but I am trying to get this car reliable for my daughter and I am making real headway, but I have to figure out this oil issue. I would greatly appreciate some insight guys. Quote Link to comment Share on other sites More sharing options...
evildky Posted June 15, 2009 Share Posted June 15, 2009 oil in the turbo inet pipe would have to cme fomr the crank case vent by the distributor if i recall the stock piping configuration correctly, which means major problme, likely cracked pistons Quote Link to comment Share on other sites More sharing options...
madkaw Posted June 15, 2009 Author Share Posted June 15, 2009 I don't believe you have recalled correctly. There is no direct pathway from the crankcase breather to the turbo inlet. The crankcase goes directly to the pcv at the bottom of the intake and it is dry. I don't believe I have cracked pistons ----CR's are right on. I realized that I am lacking info 81zxt automatic, 91k miles 135psi across the board engine is stock Quote Link to comment Share on other sites More sharing options...
stravi757 Posted June 15, 2009 Share Posted June 15, 2009 well i guess a way to see if its coming from the valve cover for sure would be to disconnect the hose to the valve cover and put a small air filter on the valve cover instead and see if it gets covered in oil when you run it....maybe a place to start. Quote Link to comment Share on other sites More sharing options...
510six Posted June 15, 2009 Share Posted June 15, 2009 If the PVC isn`t working correctly the large amount of vacuum at the turbo seal could cause oil to be drawn into the intake piping. If there is a large amount of side play in the turbo oil could be drawn into the intake tract directly from the turbo due to a bad seal in the turbo. I had this happen on a Volvo 740 turbo, after a JY replacement the oil went away. Quote Link to comment Share on other sites More sharing options...
evildky Posted June 15, 2009 Share Posted June 15, 2009 sorry, all these Z's blend together, been a long time since I had stocn managment on an L28ET, my Z32 pipes the some fothe crak case vents itn tohe pipe bewteent he mas and the turbo inlet Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 15, 2009 Share Posted June 15, 2009 Cracked pistons?? Might have issues besides a little oil in the intake. I assume all of the PCV are hooked up in their original locations? As you probably noticed, the PCV system is pretty simple. Valve cover to afm boot, and crank breather to the bottom of the intake. So there really arent many sneaky things that can be wrong with the system ITSELF. Do the fins on the turbo look oily, maybe its impossible to tell. Its really important to know if its coming through the turbo, or from the turbo. As for the turbo to J pipe boot, a vacume leak is a vacume leak. That could be your idle problem, will probably help you build more boost as well (you wont be bleeding it off anymore). As for a way to see if its the valve cover, Im not sure. My best guess would to like stravi mentioned pull the tube off and start the car. (plug the afm boot first) Im not sure if the oil can be drawn in only by the higher pressure of the block, it might be neccesary to have the greater pressure difference with the pressurized block and vacume of the afm tube. Lastly, about how much oil is there? Pools, or just a mist? Is it gungy like its been exposed to hot gases (from the crank case) or does it look somewhat fresh like it came from the turbo? Quote Link to comment Share on other sites More sharing options...
madkaw Posted June 15, 2009 Author Share Posted June 15, 2009 Yes the turbo has side play, but the car runs good with no noises coming from the turbo. I know I am probably avoiding the reality that I will have to replace it, but the path of the oil leads me to think that it is being drawn into the turbo from the vent. I will admit right now that my knowledge of the principles of turbocharging are a bit shakey so thus the questions. 510six-the way I read the FSM the normal path for the venting in the pcv would be a vacuum at the line in the AFM boot. So if the turbo was spewing oil back into the afm boot the line would be sucking it back into the valve cover? I will be replacing the pcv valve , but it seemed to be operating ok. There is no oil in the line from the crankcase to the pcv. As far as how much oil, it looks like it has been sprayed into those areas, but not enough to pool. I first discovered the oil on the spark plugs doing a routine check on how the new plugs looked. The PO had champion plugs in it when I first got the car and I believe the AFM was shot becuase the plugs looked very carbon fouled(it ran like sh%t and died at intersections) At that time I did NOT notice oil on the plugs. After getting the new AFM and fixing many other items(see my project thread-bought my daughter a 280zxt) and after a few hard runs(you know dads) I saw wet oil on the threads of the plugs. The oil was burning off the tips and there was some discoloration on the plugs, but I was also running a ton of injector cleaner also. No visble smoke coming out of the exhaust that I have seen. I tried looking into the inlet of the turbo and it looked clean and I couldn't feel any oily residue when I was checking for side play. I might clean everything down and get rid of the oil and externally vent the valve cover to a catch can and see what happens. Mean while I guess I better look for a turbo replacement-any suggestions? Quote Link to comment Share on other sites More sharing options...
madkaw Posted June 15, 2009 Author Share Posted June 15, 2009 Let me throw this fact into the mix also. I just finished fixing a excessive fuel pressure problem with this car. My return line was clogging and fuel pressure was off the scale of my 100psi tester. I know excessive fuel in the combustion chamber can wash out the sealing effect of the rings, can this be the case with a fuel injected engine? Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 15, 2009 Share Posted June 15, 2009 I wouldnt go strait to your turbo being bad... Quote Link to comment Share on other sites More sharing options...
510six Posted June 15, 2009 Share Posted June 15, 2009 "510six-the way I read the FSM the normal path for the venting in the pcv would be a vacuum at the line in the AFM boot. So if the turbo was spewing oil back into the afm boot the line would be sucking it back into the valve cover? I will be replacing the pcv valve , but it seemed to be operating ok. There is no oil in the line from the crankcase to the pcv." What the PVC system does is to use a one way check valve to allow the crankcase blowby to be burned in the intake manifold. If the check valve becomes stuck it can cause vacuum to pull oil past the turbo seal(when the throttle slams shut), if there is play in the turbocharger shaft the oil has an easier path around the seal. Quote Link to comment Share on other sites More sharing options...
madkaw Posted June 16, 2009 Author Share Posted June 16, 2009 I think my plan will be to clean it up and put it back together with a new PCV and see what she does. Now that I have eliminated some bad stuff like the fuel pressure deal, I can start narrowing things down. Meanwhile I will start shopping form a turbo. Quote Link to comment Share on other sites More sharing options...
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