Changing Spark Plugs and Now it sends Indian signals

ascensions · Post by **ascensions** » October 16th, 2006, 7:13 pm

Here's the question: If oil was leaking out of the valve cover gasket around the spark plug bores, leaking down into the hole, could oil pass through the threads of the plug and cause oil smoke out the exhaust?

Is this even possible?

The dilemma is: I changed the spark plugs the other day. I removed the valve cover after the porcelain insulator broke off of one of the plugs, & to better access the hole and retrieve the broken insulator.

I Put everything back and now the car smokes. It's lite to non-existent at idle and heavy under load.

I'm under the impression either the gasket is leaking causing oil to seep into the cylinder. There is evidence on cylinder #4 of oil in the spark plug hole. (but there was also evidence of this prior to the s.p. change.)

OR

Serendipity happened and and something caused damage to the valve after I started the car when everything was done.

The problem with scenario one, is how could oil get past a tightened spark plug.

The problem with scenario two, is the car runs smoother and better since the plug change. It idles perfect at 700 RPM, and pulls hard to red-line with more power then it did before the aforementioned "tune-up from hell."

Ideas? Suggestions? or Has anyone experienced similar?

Please set my mind at ease and tell me oil can go past the spark plug?

torpedan · Post by **torpedan** » October 16th, 2006, 8:13 pm

How long has your car been smoking? One of the common things that can happen is that oil will build up in the plug hole, when you remove the spark plug it drains into the combustion chamber. Once you start your car it will start to burn the oil and will smoke for however long it takes to burn off the oil.

Oil can work its way past the threads and into the combustion chamber, although if it is leaking enough oil to do this you chould look into changing your valve cover gasket and fixing this leak.

ascensions · Post by **ascensions** » October 16th, 2006, 8:50 pm

It didn't smoke prior to changing the spark-plugs. I've driven it a total of about 70 miles and it hasn't cleared out. It has also used oil, which it never did before, so this is something following the changing of the plugs. I do know the valve cover gasket should be replaced, I am just surprised to think enough oil could get past the plugs and into the cylinders to cause the smoke.

I should have the gasket in a few days and can check, but honestly I was looking for some consultation as to this being a common symptom in MX-3s. I'm a bit scared to think an immediate failure of a valve or valve seal may have happened.

torpedan · Post by **torpedan** » October 17th, 2006, 12:11 am

Its possible you did not tighten the plugs enough as well, letting any oil that would be leaking in down into the chmaber. Keep in mind plugs do not need to be super tighter and over tightening a plug is a VERY bad thing.

mitmaks · Post by **mitmaks** » October 17th, 2006, 12:26 am

torpedan wrote:How long has your car been smoking? One of the common things that can happen is that oil will build up in the plug hole, when you remove the spark plug it drains into the combustion chamber. Once you start your car it will start to burn the oil and will smoke for however long it takes to burn off the oil.

Oil can work its way past the threads and into the combustion chamber, although if it is leaking enough oil to do this you chould look into changing your valve cover gasket and fixing this leak.

thats what most likely happened, I did my spark plugs and it has done same. Smoked for couple days then when all oil burned out it quit smoking

ascensions · Post by **ascensions** » October 17th, 2006, 7:26 pm

Okay I just had a moment of eureka, and maybe you more technically inclined individuals could tell me if it's plausible.

Lets say, just by chance, the timing belt slipped on restart. Would a slipped timing belt provide symptoms of oil burning?

Tunes67 · Post by **Tunes67** » October 17th, 2006, 7:42 pm

No it wouldnt. Burning oil or leaking oil are the only ways you will be losing oil. Burning oil is when oil is either getting past your oil control rings or getting past your valve seals. Though in some instances.. oil can drip down into the cylinders as described above. Also.. you dont mention what your old spark plugs looked like. Can you post a pic of them? You did mention how much better the car is running now.. even though its smoking a bit. Is the smoking consistant? Or does it seem to do it more when you shift or when you first start the car?

Were any of your old spark plugs severly caked with black carbon? (Which is why I would like to see pics of them if you still have them.)

Cheers

Tunes67

torpedan · Post by **torpedan** » October 17th, 2006, 8:35 pm

The best thing to ask is were the spark plugs coverd in oil when you pulled them out. This would be the first inidcation that a ton of oil drained into the combustion chambers when you changed the plugs.

Tunes67 · Post by **Tunes67** » October 17th, 2006, 8:42 pm

I changed the plugs on a EX GF's Corrolla once.. #3 plug was so caked with carbon that it wasnt capable of sparking to ignite the fuel.. After replacing the spark plugs.. it blew smoke for a week burning everything out of that cylinder once it could actually spark again. Likely a very rare occurance I would think.. but something I thought to check here since changing the plugs seemed to make a relatively large difference in engine performance.

Tunes67

ascensions · Post by **ascensions** » October 17th, 2006, 9:05 pm

Well the deal is this. Long Version.

Car ran great, slightly rough idle, but nothing wrong. No smoke, excellent pickup. Then the muffler fell off. I went to Advance Auto and picked up a thrush turbo, slapped it on and everything went perfect. While at the auto store I bought a set of plugs to put in. This is when everything went down hill.

Cylinder 1 and 2 and 4 came out without a problem.

Spark plug 4 had a little oil on the boot and I remarked "better replace the valve cover soon"

Cylinder 3 had the the broken porcelain insulator around the bottom of the spark plug well preventing me from putting the socket over the nut portion and removing it.

When I was unable to clearly see what was obstructing the socket, I removed the valve cover to gain a closer look.

Eventually after vacuuming and scraping the porcelain from the bottom of the well, the socket fit over the plug and it was removed in a normal fashion.

It was obvious previous mechanics/owners had bypassed replacing this plug because of the obvious extra work needed. It was worn down more then the other 3.

Overall the plugs were worn and dirty with moderate to heavy carbon buildup, but not any more then I would think a plug would be from being used past it point of functionality.

So all 4 plugs went in, the cover went back on. I did reuse the old valve cover gasket, assuming if it leaked heavily I'd replace it, but it didn't seem to, so I assumed everything was fine.

I placed four new wires on the plugs. and started the car.

Here's where the dilemma comes in.

A louder then normal valve noise occurred at start up, and then quickly quieted. I worried for a second but then noticed the PCV was unplugged, and assumed it was sound venting from that hole. The car ran and idled fine with no noticeable smoke.

I got in the car and drove about 25 miles. When I got back I noticed a carbon stain on the rear of the white bumper from the muffler. I pawned it off on carbon buildup, or the oil on the muffler they use when they store the mufflers in the factory.

The next day I drove to work and noticed heavier smoke when the engine was under-load, which became less noticeable on the highway.

When I got home I popped the valve cover and siliconed around the spark-plug holes. I also pulled #4 and noticed the threads were covered in oil. This is when I wrote the original post assuming it was the valve cover gasket.

The gasket is on order, but my worries are mounting as today the car stumbled and hesitated during acceleration at idle. Heavy smoke now trails the car at all speeds.

I'm perplexed. If there was noise from the valve-train, I can't imagine anything that would cause such a sudden oil leak. My only theory are that one, a valve seal got damaged or two, the timing is off causing incorrect engine vacuum and causing blow-by. Both of these seem like "way out there" ideas since this would have had to happen ironically, and coincidentally with the car just sitting there and nothing being done to it.

The truth is I still can't quite rectify in my head if the noise on start-up was something "bad" going on or a normal cold start with the PCV out and the hood up.

Which brings me back to the valve cover gasket, which I can't imagining causing this much smoke. Unless again it's some pressure issue.

Rings don't go instantly bad, and a head gasket is also doubtful being the car was just sitting there.

Unfortunately I don't have the old plugs, but this car ran perfectly before hand, and I can't come to any possible explanation.

Tunes67 · Post by **Tunes67** » October 17th, 2006, 9:59 pm

Lets get a bit more information.. What year is your RS? What brand and type of spark plugs did you buy and install? What brand and type of spark plugs were in it originally? I'll assume its a 5 spd.. correct me if I am wrong. Are you 100% positive no debris from the broken plug insulator fell down into the cylinder when you pulled the plug? I'd recommend replacing that PCV valve as well. They are cheap so why not.

Do you have access to a compression tester?

Tunes67

WingleBeast · Post by **WingleBeast** » October 17th, 2006, 11:32 pm

sure a peice of porcelin didnt stay in the cylinder, i woudl imagine that woudl cause all sorts of issues....

it sounds like valve seals, cause mine smokes under load and thats the issues with my car. weather that is related to the sparks plugs or not im not sure... dosent seem possible. unless cylinder 3 wasent fireing, had been leaking all this time, then now with new plug the leak has become evident

PS rings can all of a sudden go bad, if there was detonation, or somthing in your cylinder... peice of spark plug.. it could cause all sorts of issues. however if there was a peice of it in the cylinder i woudl imagine you would be hearing it all the time

ascensions · Post by **ascensions** » October 18th, 2006, 6:38 am

It's 95 MX, 4 Cyl (obvious) DOHC. 5-Speed.

Unfortunately I don't have a compression tester at the moment.

Could something have fallen in the cylinder? I imagine it could have, although the hole was fairly clean of debris before removing the spark plug.

Tunes67 · Post by **Tunes67** » October 18th, 2006, 12:12 pm

At this time.. thats the most likely scenario. Sounds like a piece of the spark plugs ceramic insulator dropped into the cylinder and then crunched up at start up.. which is probably the strange sound you heard. The crunched up ceramic has since been making hamburger of the rings on that cylinder. This is speculation of course.. I am not there to check in person.. but the logic fits the circumstances. I'd do a oil change ASAP.. but I think its likely too late to save it. And also a compression check.. check to see if #4 has lower compression than the others. On a positive note.. these engines are fairly easy to find and inexpensive. You sound more than intelligent enough to do the work required.. if that is the route you wish to go. You could also swap in a BP engine which would give you a nice power upgrade and would be only slightly more expensive than replacing what you have currently.

If you can do the work yourself.. it wont be that expensive. If you have to have a shop do the work... It will get very expensive. Cheaper to buy another car.. maybe even another MX-3.. then you have lots of spare parts

Best of luck.

Tunes67

ascensions · Post by **ascensions** » October 18th, 2006, 1:09 pm

Thanks for all the suggestions. I've spent the last few hours trying to troubleshoot. I'm still stupefied.

So far I've pulled the cover and watched the flow of cams. No noises nothing odd.

I've pulled one plug at a time to see if it was a particular cylinder, and yet still no go. My assumption was take out the spark and it would stop smoking. This never happened.

When I pulled the new set of plugs, #1 was clean, #2 was oxidized, #3 was fouled (looked like oil) and #4 was carbonized. It was like the entire spark plug chart in one car.

My assumption was that it was #4 originally, but now It looks like #3.

This is when I wondered if perhaps what I thought was porcelain around the base of the old plug was maybe actually some sort of sealant with porcelain in it. Maybe a plug repair? The reason this warranted investigation is even though the plug was damaged originally I could tell it wasn't the exact same plug as the other three. But I assumed this was simply a different brand, and when the new plug just slid in and tightened down no differently then before I didn't see a problem. When I pulled each plug one at a time, I checked for pressure leaks, and couldn't tell of any particularly.

So back to square 1. Other then doing a cylinder pressure test I'm out of ideas. I'm going to swing by the store and pick up a gauge or take it over to a local shop, depending on cost.

Does anyone know if a standard pressure gauge fits all the way down in the hole? Or is there a special adapter for the OHC vehicles?

If compression comes back fine, both wet and dry, where does that leave me?