oily #4 plug (2 Viewers)

[DirtScaresMe]

I've had an on-again-off-again code 26 (mixture too rich) getting thrown. It seems to show up maybe ~10 minutes into the morning, and after the engine warms up it goes away.

Around the same time I've had some rough idling as well.

The code and rough idle seem to go away at similar times, when the engine is warm.

I yanked my plugs before an inbound snowstorm to see if there was anything weird on them, and #4 had oil on it both on the threads and up on bolt head (where the socket grabs it). I think it also "hissed" a little when I opened it, like it was under pressure in there. I tossed in a new plug.

Not sure if any of this is related, open to theories. The offending component:

 

[BILT4ME]

The oil on top is from your spark plug tube seals at the top of the VC.

The oil on the threads is running own from the top as you loosen the plug. The tip of the plug does not look wet.

 

[baldilocks]

Oil in the spark plug tubes is listed in the fsm as the #1 cause of misfire.

 

[DirtScaresMe]

So I'm looking at:

Pcv valve
Pcv valve gasket
Spark plug tubes
Plugs
Valve gasket

Anything else while in there?

 

[baldilocks]

Throttle body gasket and some RTV or gasket synch to keep the valve cover seal in place while you install the cover on the head.

 

[DirtScaresMe]

Cool, thanks guys. Curiously how bad is it to drive like this for a bit? I'll fix all this before my next big multi-hundred mile trip but am I screwing anything up long term by rolling around for 100-200 miles of town driving?

 

[BILT4ME]

Also may as well do the Dizzy O-ring, Plug wires and every vacuum line you can reach.

May want to consider having on hand a heater valve since you will have to be tugging on the coolant lines directly above the VC. Get that one from Rock Auto.

Plan on replacing all the coolant hoses above the VC if you do have to open it up.

AND FOR GOD'S SAKE, DON'T BREAK OFF THE NIPPLE ON THE RADIATOR!!!!! Oh....wait........you have a 94....I don't think you have one. You have the brass radiator.....right?

 

[DirtScaresMe]

Also may as well do the Dizzy O-ring, Plug wires and every vacuum line you can reach.

May want to consider having on hand a heater valve since you will have to be tugging on the coolant lines directly above the VC. Get that one from Rock Auto.

Plan on replacing all the coolant hoses above the VC if you do have to open it up.

AND FOR GOD'S SAKE, DON'T BREAK OFF THE NIPPLE ON THE RADIATOR!!!!! Oh....wait........you have a 94....I don't think you have one. You have the brass radiator.....right?

When you say coolant lines are you talking about the loop thing back by the firewall? I had to motivate that a bit to pull the last plug out. Looked like the kind of thing you need to rip apart and re-assemble with new materials.

I've always wondered what people are talking about with the radiator nipple; the only thing sticking up for me is the cap. Not sure what it's made from, I have an OEM replacement on the way as well. There's a small leak in the top (sometimes; it's literally a few drops / week), but I'd rather just replace before it gets to be an issue.

 

[BILT4ME]

Yes on the coolant lines by the firewall. Originals have a clamp with a cotter pin in them. I would replace with Gates Greenstripe and constant torque clamps (gotta get those online....no FLAPS carry them) but if you can't get the constant torque ones, get high quality hose clamps. Otherwise, buy all from local Toyota Dealer.

On the 95-97, it is a plastic tank on the top and bottom of the radiator. There is a little hose nipple that sticks straight back towards the engine and it is molded into the top tank. If you are leaning over the top of the radiator, you will press down on the nipple and break it off.

The PHH is "part" of that loop, but way down low on the left side (DS-USA) of the engine. If you decide (or are forced to do the heater lines) then do the PHH at the same time as well as the sorta PHH (just higher up....)

 

[riffman12]

I had similar symptoms on an old bmw inline 6 back in the day. It was the seal around the spark plug attached to the VC gasket.

 

[DirtScaresMe]

I had similar symptoms on an old bmw inline 6 back in the day. It was the seal around the spark plug attached to the VC gasket.

I just ordered the necessary oem parts. By Friday they should be here.

Any theories on exactly how bad it is to stack on another few hundred miles before I fix this? If the oil isn't in the cylinder than the problem is the oil messing with conductivity from the wire to the plug?

 

[riffman12]

if it's actively misfiring and running funky I'd probably try and avoid driving it.

You can maybe try putting a hunk of dialectric grease on top of the spark plug as a patch fix in the mean time to help with conductivity.

 

[DirtScaresMe]

I'm wondering if the problem I've had (random code 26, rough idle when starting cold) is even related to this. In the picture (top of the thread) there's zilch oil on the electrical connection at the top and I didn't see any on the wire-plunger-thing that connects to it.

I definitely want to fix it, I'm just curious if it's a false positive and even making any sorts of problems. Like if it was mis-firing because of this, I would think it would happen all the time and not just be a rough-idle-when-cold sort of thing.

 

[baldilocks]

Do you have an fsm?

 

[DirtScaresMe]

Do you have an fsm?

I do, is there a page I should be eyeballing?