Noob Needs Help: Stuttering + Blew Out Some Oil

[ThisIsSparTTa]

Hey guys, I'm new here, so be gentle. I got my 91 300ZX TT this past week and I have a laundry list of things that need to be done to her, but this is basically the tops (plus getting cats put back in) so I can pass inspection. I've been doing plenty of research trust me, but the latest permutation to the problem below now has me worried, so I'm going to go ahead and post.

Before I bought her this week I took her to the Austin Z Clinic to get checked out. Kevin (owner) immediately noticed as soon as she started that she was misfiring (I have bad hearing so I have to stand at the rear to hear it). He hooked up his diagnostic tool, and then listened via a stethoscope, and said one of the injectors wasn't firing (I don't know if he said which). He recommended an injector replacement.

I negotiated the purchase price, had her driven ~5 miles home. Since then I've observed the sound myself tinkering around with her idling in my garage. I think sometimes all 6 cylinders are working properly, and sometimes 1 or even 2 misfire. The exhaust pattern either sounds smooth, has one obvious constant stumble :pfft: :idleidleidleidleidle: :pfft:, and sometimes has 2 :louder pfft: :idle: :softer pfft: :idleidleidleidle:. Obviously those hard to put in words, and there aren't necessarily 6 parts to the cycle (probably more). Anyways, since getting her home, I've taken her for a spin 3 times for less than 5 miles, and I've pushed her some, but not too hard.

Previous to being sold she hadn't been driven much lately, and as such the oil filter had some date from 2010 sharpied on it, so I wanted to change the oil. Royal Purple 10W-30 had been used before, so I grabbed 5 quarts of that. To keep this long post short, suffice to say she was jacked up on the drivers side, tilted, for 2+ hours due a missing socket that I had to go buy and then a buying a proper sized oil filter wrench too. Also, the drain plug and filter were off for a little while too. The reason I make a big point of this is in case it could have some effect on fluids shifting to one side, and or possibly flooding over to somewhere they shouldn't have been.

I drop her down, do a couple things, crank her up. I take my new stethoscope and listen to each injector, I hear what I think is supposed to be the clicking from each injector, but she's still stuttering when I listen to the exhaust. Before, the stutter pattern has changed after revving, so I rev to 2-3k a couple of times, and go to the back of the car, and notice a little smoke (not currently coming from the exhaust), and what appears to be oil sprayed on a carboard box I had behind the car. Upon further inspection it's definitely fresh as well as some on the ground. I cut the engine, there's a fair amount of smoke, but not ridiculous and not coming from any one place. The amount of oil was very small, just some that had been blown out.

So, now I'm a bit scared, she wasn't smoking AT ALL before, and to my knowledge hasn't spit oil like this when I've tinkered before. I couldn't find much on the topic of oil spitting out except when turbos go bad, which would be really strange to happen after a oil change...

1) Any thoughts and ideas on what could cause it to spit oil? Is it safe to crank again? What would I do to troubleshoot this?
2) Assuming the oil thing is a fluke, any thoughts on the misfire if it sounds like the injectors are firing/clicking? I'm not doubting the mechanics analysis, but I'm working to ramp up my knowledge and understand my car a little better.

Edit: This morning I cranked her up, ran fine at idle, sometimes missing, not spitting oil. I revved, and she spit oil on the passenger side, and then had small amount of white smoke only on the passenger side. Cut the engine, and now she sits again. Note that yesterday she spit oil on both sides.
Edit2: Was reading service manual this morning, and it said 3-4 quarts? I went and checked the dipstick and reads right at 'H'. http://www.300zx-twinturbo.com/cgi-bin/ ... t&total=33
Edit3: I've been trying to read more on this this afternoon. Seems that white spoke is more likely to be coolant. I did find the resevoir tank empty, and the radiator drank a good bit of 50/50 mix, and then I filled the resevoir tank up to H. I would say this is odd though because what comes out of the exhaust seems to be more like oil, but I guess it could be gunk from inside the exhaust.

[z32loverboy]

Well, if you think its the injectors the easiest test is to Ohm them out with a volt meter and they should all be around 12.6 ish if i remember correctly. If you're getting oil out the exhaust i would check compression and make sure your rings are all sealing decently 190-ish compression is perfect but like 170 ish is okay. if that checks out next I'd do a leak down test. that will test to see if the compression is passing by the piston rings (the rings can make compression and also still let it by). There's also the possibility that it's a head gasket. Blue smoke means oil and white usually means coolant. There's a tester you can buy that tests to see if there's compression gasses in the resevior tank. you can use that to see if the head gasket is blown. Run those tests and see what they come up and let us know what they say

[ThisIsSparTTa]

Thanks! I actually went out and idled her for about 10 minutes. For the first while water was coming out of the passenger side exhaust only, just at idle. I have now verified it to be what I believe is water/coolant because I had taped some towels to a box to catch the oil, and some liquid landed on the tape itself and appeared to be ~clear and not oil. I previously assumed it was oil because it was blackish, but I think it was just catching some exhaust junk, or even just some of the crap that builds up around the tips. Anyways, after a while the water ceased. However, it is occasionally putting out some white smoke, but that seemed to be ramping down as well. I have my fingers crossed that it either had something to with having the car tilted for so long and/or refilling the coolant. Please let me know if I should still be cautious for now.

In regards to ohm injector testing...I have to admit I'm really not sure what I need to to get to the injector to test it. There are plenty of guides for replacing them, but I can't seem to find one for testing. Is there a guide or can someone describe how to get to the injectors for ohm testing?

As for the other tests, those are a bit daunting to me at the moment, but I will surely step up and learn how to do them if I need to. I also intend to check the ECU for codes later on today. One last quick note, while paying so much attention to the exhaust just now, I noticed that the stuttering seems to be exclusive to the driver side exhaust, so I probably focus in on there first.

Edit: I'm still not sure how to get to the injectors in the engine bay without a plenum pull (is there a way?). For now I've found the pins I can check at the ECU harness, so I'm going to try that: http://www.twinturbo.net/ttnetfaq/FAQpa ... rness.html

[ThisIsSparTTa]

Alright, so first I checked out the ECU and realized that with the other stuff thats been done to the wiring I didn't want to mess with it right now. On a side note, the ECU is showing code 34, detonation sensor, but at a glance it looks like the connector under the hood is a bit shady. I'll get to that later.

I took off the throttle cover, tried my first injector connector, successfully broke the fragile red part like everyone says (is there anything I need to worry about this). Right now I cant get it pulled off, am scared to try any harder, and don't see any other snaps or anything to work with. How do I get these guys off? Maybe draw on my image if that makes it easier?

[z32loverboy]

Alright well if its throwing the detonation code I would double check the timing and make sure that was right. I wouldn't worry about breaking "fragile red parts" too much, as long as the connector doesn't shatter you're good. and even then you can order replacements to splice in from Z1

There's a FSM (full service manual) in the "everything you need to know about the z32" sticky at the top of the technical page. It's one of the best things ever and also read the whole sticky. It has a lot of information in it and it answered many of my questions when i first got my Z.

There's a groove in the injector connector and it had a metal clip that holds it in. You have to remove the clip to be able to pull the connector off. there will be two metal pins coming out of the top of the injector. take the positive end of the volt meter and attach it to one pin and the negative to another while it is set to test "Ohms". You're looking to find a injector that isn't around 12.6 ohms. the reading will bounce around a little but if you play around with it you'll figure it out.

The rest of the tests sound more complicated than they sound. Basically you remove the fuel pump relay and pull the spark plugs out and attach the compression gauge in each hole and it'll give you a number and that number will be your compression for that cylinder. A leak down is similar to the compression test. Don't let these things scare you too much, just ask questions and do your research. We've all been there and whoever says they haven't is lying. Keep us updated
-Tyler