No Spark, Oil and carbon all over plugs (pics)

[speed]

So I'm driving on the freeway heading down to go to a party and help WeezL out with his car, when all the sudden, the motor just dies. No sputtering, weird noises, puffs of smoke, it just dies. I pull over (mind you while its pourding down rain, windy, and bigass trucks are roaring by), I've got fuel pressure, so I check to see if I get spark.

I pull out plug #1 and its COVERED with oil. Clean it off, but theres still a fair amount of carbon buildup. Pull out #3 and 5 too, same thing. Call tow truck, get home, and take the rest of the plugs out:

I found that one of the wires from the o2 sensor had melted over the exhaust manifold, so i checked to see if my o2 sensor is bad. TSRM calls for resistance between 3-3.6ohm, mine is 4.8- aka bad.

So the bad o2 sensor explains the carbon build up (plus its been running a little rich lately). Now what about the oil? Theres no oil anywhere outside of the motor. I scrapped a small sample off the top of the cylinder head, its hard to tell what it is, but looks like burned oil. Could this be bad valve seals? Is there anyway to check without taking off the head?

 

[bentandbroken]

I did a compession test this weekend and my #5 and #6 were oily, not as bad as yours. I was told by the guy helping me that it's normal for the rear two to be that way on this motor. He has owned and modified MKIII since '99. He told me why, for the life of me i can't remember what he said.

I'm sure some of the guys on here will have a better answer. Sorry i wasn't much help

 

[jetjock]

Allow me to clue you in here. The O2 sensor can't be ohmed. In fact it's bad to do it. What you measured (and what the manual is referring to) is the sensor's heater and it's resistance will change with temperature. Regardless of what Toyota said you can't know the condition of the sensor because you can't test the actual sensor part of it that way. Fix the melted wiring though. As for the oil it likely came from a loss of ignition. Will the car start now with clean plugs?

And for the second poster no, it's not normal for the two most rear plugs to be any worse than the rest on a healthy motor. Your buddy is clueless. Is this the same genius who thinks using a hose (without even a draft tube) on the PCV system is harmless?

 

[Josh Sulsberger]

For the oil on the plugs, I would inspect the valve covers. Mine basically filled up the galley when they were loose. You couldn't see it from the outside. when you pull the spark plug wire boot off and look through the "spark plug galley cover" you could though. When you pull the plugs themselves, the oil goes into the cylinder...

 

[jetjock]

Yeah, you may be right. The outside of some of those plugs look bad while some aren't fouled. Plus the socket in the top photo is oiled. I don't think along those lines because I've never had leaks on the covers. I wonder why the car just shut off though.

 

[Obsessionw/Boost]

I pulled one of my wires today and the plugs are completely submerged in oil, I dont know how, but Im ordering a valve cover gasket immediately, I'm going to sap up all the oil thats in there, I'll try my best so that when I pull the plug, oil won't go into the cylinders....

 

[suprahooked]

Is it possable that the ignition fuse blew? Or you lost ground from the igniter box?

 

[speed]

Thats kinda what i'm starting to think. I cleaned all the plugs really well, put em back in, no go. took out 1 and 4, no spark from either. I'll check fuse and grounding after dinner.

 

[suprahooked]

The ground on the ignitier is the case itself, Make sure you sand a fresh spot under the case before you bolt it back down .

 

[supra90turbo]

Yep, I made that mistake once before, went to start my car to move it and no go. Forgot that I had unbolted the igniter from the fender skirt.
Bolted it back on, and it fired up without a hitch.

 

[jdub]

The ground on the ignitier is the case itself, Make sure you sand a fresh spot under the case before you bolt it back down .

The ground for the ignitor is crap...this is a much better way:

http://www.mkiiitech.com/forums/viewtopic.php?t=857

 

[speed]

okay, checked the ignitor, its fine. Checked wiring to coils, they're fine. Checked plug wires, they're fine. That leaves the coil and plugs left. The way the TSRM says to test the coil is a bit vague, is there a better way of doing it?

 

[Halsupramk3]

if the spark plugs were submerged in oil and oil gets under the spark plug caps it may cause ignition problems. I would not think it would shut off the engine tho. if the oil is deep enough it would run crappy.

 

[jetjock]

I don't see oil getting past the plug seal, plus it's a dielectric.

speed: *How* did you check these things? One of the things that bug me here is seeing people all the time saying "I checked this and that and it's fine" when for all I know they haven't a clue how to check things properly. In fact that's more often the case than not. Sorry but but based on your checking of the O2 sensor you don't strike me as particularly savvy in the electrical/electronics department. Answer one question: does the tach flicker when the engine is cranked? Are there any codes? Ok, that's two questions...

 

[speed]

Being as I've never dug into a supra's electrical system, the best guide I have is the TSRM.

Yes, the tach flickers, and no, no engine codes.

 

[jetjock]

It's OK, we all had to start somewhere. You might want to invest in a EWD. It's an electrical gold mine compared to the TSRM.

If the tach flickers the igniter and at least one coil is working. Guess you were right when you said you checked it .

No codes (specifically code 14) is another good sign. The odds are excellent you have spark. If anything you could have bad plugs or wires but the odds of that are slim. Although I dislike telling people this you can pull a plug wire to confirm spark but your coils are working. If they weren't the tach would not flicker.

 

[speed]

I'm not sure how old the NGK's are that are in the car, so I'm going to go ahead and replace the plugs tomorrow. Needed to be done anyways, might as well just buy em

 

[jetjock]

Ok, good deal. If you have a timing light you can also use that to check for spark. Next time you're in an auto store you may want to pick up a $5 spark tester. Looks like a plug with a big clip on it and a window to see the spark. A handy item for times like this. Repair the melted wiring on the O2 harness and get back to us. I'll walk you through testing the sensor before you splurge on a new one.

 

[johnathan1]

Yea, the o2 sensor wiring is likely what caused you to stall...I've heard it happen I think like twice on here, the o2 wires ground on the compressor housing, and blow one of the fuses (IIRC it was the EFI fuse)...

I'll try to find the thread I'm referring to...

The oil on your spark plugs is from leaking valve cover gaskets.

Also, the oil going into the cylinders isn't really a big deal...any that falls in will burn up within a few seconds.

 

[jetjock]

Whoops, working too many forums at once. I wonder what the guy with GTSW question is wondering right now since I doubt he owns a Supra. I'd better go fix that.

Johnathan's right. I remember that thread now and an O2 sensor heater short to ground will blow the EFI fuse. Nice job Johnathan.