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Discussion Starter #1
Good afternoon fellas!

Came across another issue with the Supra and thought I'd run it by everyone.

A little background: I went out for a cruise the other day and after going through a gear of boost, the car felt like it hit a wall. Afterwards, it wouldn't idle and pretty much sounded like a cammed V8. While limping home, I noticed that I was running WAY rich (7-8:1 range under throttle and at idle).

Today I finally had some free time to get under the hood. I pulled the plugs and noticed 4 of the 6 were pretty much coated in oil. The remaining 2 were a deep black.

Here is a picture:


The part that concerns me is that these plugs have no more than 100 miles on them. I, literally, just changed them out a few weeks ago while doing cleaning up some other stuff. The plugs that were previously in the car were the exact same, but did not show any indication at all of any oil.

Here is a picture of the previous plugs:


So what do you fellas think? Any help at all would be appreciated.
 

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I think you blew a intercooler hose which causes the richness and the oil on the plugs could be from old valve cover gaskets. The gaskets are a common problem and are easy to replace.
 

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Discussion Starter #3
I think you blew a intercooler hose which causes the richness and the oil on the plugs could be from old valve cover gaskets. The gaskets are a common problem and are easy to replace.
The intercooler piping was the first thing I checked - had one pop off before. This time, that doesn't seem to be the problem.

Ironically, I put brand new OEM valve cover gaskets in the car no more than a month ago (put in some 264s) so I don't think that would be the problem. I am going to pull them and double-check this weekend to be certain though.

Would damage to the rotating assembly cause something like this? For some reason, the first thought I had was oil coming up from around the piston rings or crankwalk - but I'm no mechanic. I'm pretty much not ruling anything out since I've had problem after problem after buying the car 3 months ago. The previous owner said the engine was rebuilt 3-4k ago, but seeing some of the wiring and the consistent issues with the car has damaged my trust in words anymore.
 

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Un4GvnLude said:
The intercooler piping was the first thing I checked - had one pop off before. This time, that doesn't seem to be the problem.

.......
Did you check EVERY connection? Those are classic symptoms of blowing the IC piping. I know I didn't find my leak the first time I looked.
 

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Discussion Starter #5
Did you check EVERY connection? Those are classic symptoms of blowing the IC piping. I know I didn't find my leak the first time I looked.
I just glanced at the ones under the bumper, but I should have time tomorrow to give it a more thorough lookover.

Regardless if it was a blown intercooler pipe, that wouldn't account for the oil on the plugs - would it?
 

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Discussion Starter #7
leaky valve cover gasket.
This is the part where the oil is:


From what I can tell, the valve cover gasket is way higher than the plugs themselves. Even if they were leaking, it would come down around the coil packs - unless I'm way off. Where you thinking the porceline part was the oil soaked area?
 

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If the leak is bad enough, and on the side facing the oil galley, then the oil will leak down between the intake and exhaust cam covers. If the leak is real bad, it will fill up the socket right up to the terminal end of the plug. By then it would be obvious that you have a problem. The design is simillar enough to my NA motor, and I can't image your coil packs seal up the plugs insulator any better. I'm just letting you know it can happen on the GE motor, and I think the designs are close enough that the same thing could happen on the GTE motor.

The electrode tips in the "new" pic definately look on the oily side. That's not consistent with what I found when my valve cover gaskets were leaking, but to continue with my ambiguity, that doesn't mean it can't happen. I don't know for sure, but you may be looking at a different problem.

I'll let the mechanics here troubleshoot, but if the intercooler hoses look ok, maybe you could run a compression test.
 

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Discussion Starter #9
I got a little bit of time to run out and take a look at the area the coil packs reside...not a bit of oil in there. Since the plugs are substantially lower than the valve cover gasket, I've pretty much ruled that out since it wouldn't be coming from the coilpack side of the plug.

What else could cause the firing side of my plugs to be coated in oil?
 

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It might be just me, but your plugs in the pic look to be black from too much fuel. By my experience oil on the plug from worn engine parts (valve stem seals, rings) will cause thick caked on deposits on the plug which doesnt sounds to be the case. Post a closer pic of the electrode area of the plug.

Lawrence
 

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I have had this same problem except they were not coated - they were COVERED. The last 4 were DRIPPING with oil. I replaced the valve cover gaskets and my car runs great (have NOT replaced plugs yet!) now. I will replace them after I get my 2+ kit installed next week and let you know if that's what it is (my old turbos are leaking BADLY so it would not be fair to say the valve covers did NOT cause it). My guess is that the valve cover gaskets are the cause. Replace it again. First time I did it, I failed to properly seat the thing when I put it back down onto the engine - be sure to use the gasket sealant. I have only used Lucas upper cylinder lubricant after I replaced them and an oil change and now I very VERY rarely burn oil. I was BLOWING oil out my exhaust until i changed them. After the change I had one last mother of all clouds puff out and then it was basically over from there on out. The turbos are the cause of the remainder (i know this because there is clearly OIL gunk in my intercooler piping! AH! How do I get this out of there?!) of the oil burning problem. I wish you the best - let me know if your compressions are all ok and what the problem was. I hopefully am not in the same boat you are if it's bad compressions!
Best Wishes
 
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