: Oil on plug #2 causing rough idle/misifre?



Skiller.
03-16-10, 07:51 PM
Hey guys, I've been trying to diagnose a rough idle the past few days, but then I thought of something that I had to do when I originally bought the car.

About a week or so after I bought it, I got a flashing SES light, which I knew was a misfire after looking at the owner's manual. This was before I joined the forums, so I took my car to autozone (lol) to get a diagnosis. They told me, "misfire in cylinder 2". I drove it home, removed plug #2 (caked with oil) and replaced it with a new plug. The misfire was cured. I eventually replaced the other 7 about a month later (with splitfire plugs). All was good until 3 months later, I got the misfire again...This time I had the knowledge from the forums and knew that the splitfire plugs could have been the problem, so I replaced all the plugs with AC-Delcos.

Again, all was good for 1500-2000 miles or so until I developed a rough idle.

Just for the hell of it, I took out plug #2 today, which had a considerable amount of oil on it for 2000 miles. I cleaned it, and put it back in. Started the car, and the idle was significantly smoother. I bet if I left it alone for a longer period of time, it would eventually start missing upon acceleration...

I guess I'm asking if anybody has ever heard of this happening with our cars?

Cylinder 2 seems to be the only one that I'm having issues with...6 of them are always bone dry (1,3,5,7,6,8).

2 and 4 are the only cylinders that get oil on the plugs, but 4 doesn't have any firing issues...only 2 does.

I guess it could be worse...If I have to clean that plug every 3k or so to keep the car running great, I guess it's worth it...But, is there anything I can do to permanently fix the problem?

I remember seeing Johnny Kannapo post about the oil on the spark plugs being more serious than portrayed.
If you read this Johnny, maybe you can chime in! :P

Any suggestions would be greatly appreciated!

tateos
03-16-10, 08:31 PM
I think you have identified the cause of your rough idle and miss on acceleration - now what's causing the oil? Valve seals or rings? Probably the latter - maybe the rings are sticking. Try a combustion chamber cleaner soak, followed by the storied WOT beat run. I'm sure others have tried it and can offer advice and more details.

Skiller.
03-16-10, 08:43 PM
Thanks tateos, I think I remember reading about this "soak" somewhere on the internet when I originally bought the car, but I'm not aware of the details. Keep in mind that it didn't miss on acceleration before I cleaned the plug, but I'm sure that wasn't too far away (what I meant). I was only experiencing a rough idle.

tateos
03-16-10, 09:01 PM
My gut tells me a rough idle or miss at idle but not under load could be more related to fuel mixture than ignition. Can you tell which cylinder is missing? Try swapping injectors - see if the miss follows. Also check for vacuum leaks, which would cause a lean miss at idle.

Skiller.
03-16-10, 09:08 PM
I'm pretty sure that cylinder 2 was missing (that was the problem both times in the past). Like I said, I cleaned the plug in 2, and the rough idle was cured. I just don't understand why it was so smooth under load (accelerating and at cruising speed), but now, it's smooth at idle and everywhere else. I just want to avoid this from happening again in the future in 3,000 or so miles. This is the third time cleaning/replacing the plug in cylinder 2 has solved the engine running rough.

I will be replacing a faulty EGR valve, cleaning the TB, and replacing the air filter on Saturday, so that can only help things...

Ranger
03-16-10, 09:09 PM
Try beating on it with the WOT procedure several times to free up the rings first.

Skiller.
03-16-10, 09:19 PM
Before I perform the soak you mean, Ranger?

Ranger
03-16-10, 09:31 PM
Yes. If you do the soak, you MUST be sure to vacuum all of the liquid out of the cylinders or you stand a chance of hydrolocking it and bending rods or launching them through the side of the block.

Skiller.
03-16-10, 09:44 PM
Ok, I don't want to have that happen! I'll definitely try the WOT first. I hope that works. The car runs like a brand new car when that plug stays clean, so it's frustrating! It seems to me that I never properly performed the WOT procedure.

I read this: http://caddyinfo.com/northstaroil.htm

Was a good read. Start at 40 in 2nd, WOT to 70, and let it back down to 40 and repeat 10 times. I always just left it in drive, and gunned it on the thruway on ramp. I'm sure there is a reason for leaving it in second gear and letting it automatically drop itself back down to 40 before WOT again.

Ranger
03-16-10, 10:08 PM
Keeping it in 2nd will allow it to decelerate in 2nd and create a high engine vacuum and as our old Guru said "ring flutter". That tends to break up any carbon that may be caked on the compression ring and binding it to the piston, preventing it from properly expanding against the cylinder wall and rotating in the land as it should. If you do it in 3rd, you'll get a much lower RPM deceleration. Just be sure to get your foot out of it before 6000 RPM. That should be somewhere around 80. No need to go that fast or actually hit 6000. Just wind it up tight and let it back down. The tighter you wind it, the longer the decel (traffic permitting).

Skiller.
03-16-10, 10:52 PM
Thanks Ranger. Now I understand how the WOT is supposed to work. What I don't understand is, whether it's better to WOT in 2nd, or 3rd. When you said "If you do it in 3rd, you'll get a much lower RPM deceleration." Does that mean the high engine vacuum occurs for a longer period time, and is better for clearing the carbon? And whether or not I'm in 2nd or 3rd, I should let of the gas once I reach 6,000 RPMs?

Thanks a lot.

Submariner409
03-17-10, 09:47 AM
Somewhere in here, recently, I wrote a long reply about 4T80E transmissions, gears, WOT's and rpm. Find it.

The gear selector says "Drivetrain, this MY preferred gear." The transmission will stay in that gear during any time that rpm will not cause engine or drivetrain damage.

As Ranger posted, the idea is to load and unload the engine, so put the selector in 2 and do a rolling start from about 5 mph. The transmission will be in first gear, NOT second. Put your foot through the firewall. The engine will go to redline in first, then shift to second. Continue to about 6,000 rpm and flip your foot off the gas. The engine will pull vehicle speed down to a point at which a downshift will not cause damage, so it downshifts to first and continue to, say, 10 mph. It is this high-rpm second gear unload that accomplishes the major part of a WOT - not the acceleration phase.

Skiller.
03-17-10, 10:48 AM
Thanks sub..I guess that tells me that what I thought of WOT (pedal to the metal in D) really never accomplished what a WOT is supposed to. I'm anxious to perform this procedure. I need to find a strip of road where this is possible!

cmobile
03-17-10, 11:34 AM
Forgive my ignorance,

but does that car have 4 dual coil packs, or a single coil?
My next question is, if it does have the dual ignition coil packs,
could 2 of the coils be going bad and not producing enough spark to burn off said oil?

thanks,

~C

Ranger
03-17-10, 12:02 PM
Skillers car has 1 ICM with 4 coils mounted on it.

Ranger
03-17-10, 12:13 PM
Thanks Ranger. Now I understand how the WOT is supposed to work. What I don't understand is, whether it's better to WOT in 2nd, or 3rd. When you said "If you do it in 3rd, you'll get a much lower RPM deceleration." Does that mean the high engine vacuum occurs for a longer period time, and is better for clearing the carbon? And whether or not I'm in 2nd or 3rd, I should let of the gas once I reach 6,000 RPMs?

Thanks a lot.
If you reach 70 in 3rd you're at 2K. Decel is no different than a highway coast down. In 2nd you're closer to 5-6. Long high vacuum decel to 40 or 50.

6000 is close to redline and that is where the PCM will shift gears regardless of what gear you have the selector in, as Sub said. That's why you want to get out of it by 6k. Keep in mind that 6K is not a magic number. You'll be near 80 MPH so back off sooner if necessary. Safety first!

Submariner409
03-17-10, 12:18 PM
2000+ have the coil cassettes: 4 coils and an ICM in EACH cam cover.

Skiller, If you really want to go insane with WOT, do the whole thing in 1.

As posted before, at full throttle, the transmission will happily let the engine wind to redline, shift, redline, shift, redline, shift. All the way to as fast as the speed limiter will allow, all with the stick in 1.

Whoooppss !! Ranger beat me to it..........

johnny kannapo
03-17-10, 12:33 PM
I was referring to the spark plug wells filling with oil due to the valve cover leaking & fouling the exterior of the plug & the wire boot, not to be confused with spark plug fouling(the tip) internally. That much oil can only get in the cylinder 2 ways. Valve seals or the rings passing oil. Something could be running a-muck with the PCV but that would foul plugs equally and where is the smoke? Do you notice smoking? When you pull the plug does it have deposits caked on the tip? Or is it just wet otherwise looking ok?

Skiller.
03-17-10, 12:34 PM
Can I do it in 1st gear and let off the gas at first gear's redline and coast down and get the high engine vacuum??

Ranger
03-17-10, 12:42 PM
Yeah, but you'll hit redline and shift to 2nd before you realize it. It winds up REAL fast in 1st. You'll also have a much shorter decel.

Skiller.
03-17-10, 12:54 PM
I was referring to the spark plug wells filling with oil due to the valve cover leaking & fouling the exterior of the plug & the wire boot, not to be confused with spark plug fouling(the tip) internally. That much oil can only get in the cylinder 2 ways. Valve seals or the rings passing oil. Something could be running a-muck with the PCV but that would foul plugs equally and where is the smoke? Do you notice smoking? When you pull the plug does it have deposits caked on the tip? Or is it just wet otherwise looking ok?
I don't notice any smoke. And the plug looked fine other than oil on it. Like I said, most of the plugs don't get any oil on them. 2 and 4 are the worst.

Skiller.
03-18-10, 12:02 AM
Well, I performed 3 WOT procedures on the way home from school today on the highway..Traffic was light, so I figured it was a good time. I started in 2 at 40 mph. I gunned it up to about 70 or, which was only about 5200-5300 RPMs...I can go all the way to 6000 right?? That would be around 80...I let it decelerate all the way down to 40 on its own...I see how that is important. I repeated that several times; I would have continued, but I ran out of open space on the highway. I will give it a good workout again tomorrow. Should this be regularly executed like once a week or something even if I wasn't trying to fix an oil problem?? After doing it, I can see how the deceleration is good for the engine.

Thanks!

Submariner409
03-18-10, 10:53 AM
The WOT is best done from a 5 mph rolling start, WOT to shift, WOT to 6,000, foot off gas and long coastdown. The high load and unload are what does the job, not simply vehicle speed.

A WOT is not a weekly drill. It is primarily used to "exercise" a Granny car. If your car is regularly driven on the highway, with passing here and there, and is also driven in a spirited manner but intelligently, a WOT would be almost unnecessary.

For someone who likes to drive under all conditions, WOT is a normal occurrence, not a surgical procedure.

Go back and read Post #17. This is a live thread, and history is the best teacher.

Ranger
03-18-10, 12:29 PM
I have always said once a month or whenever you get the urge just to keep the rings free.

Skiller.
03-18-10, 02:16 PM
Thanks guys..Since I've had, it has seen the highway 90% of the time with occasional high speed runs, so I definitely do not baby it. The previous owner never got it above 50 mph I don't think lol. I'm sure my car needs the exercise that you speak of sub; given the fact that my O-rings are weeping a good amount in a few cylinders.

VIPERRACING
03-23-10, 08:52 PM
Im also having issues, once again, and Im glad that I rolled onto this thread. My car is a 99 sts and it is having a slightly rough idle. The car is going through oil like there is no tomorrow. Im the original owner and the car never gets beat on. Ranger or Sub, do you think the high speed decels will solve my problem or do I have to have the motor reringed? I have already pulled all the plugs and dumped seafoam in all the holes and let it sit for 24 hours but that didnt seem to solve the problem. I also drilled the oil cap so that it would help vent the crank. The car doesnt smoke but it just uses a ton of oil. What is the soaking process that you guys are talking about and what is the best chemical solution to use because seafoam didnt seem to do the job ? Thanks

Submariner409
03-23-10, 09:01 PM
What is your definition of "A ton of oil" ???

#1. NEVER dump magic potions into a Northstar. The engine doesn't need them. What you did with SEAFOAM is pretty close to the Cadillac chemical ring cleaning procedure.
#2. Put a new oil filler cap on the cam cover. The PCV system depends on a set range of crankcase airflow to do its job. Extra holes do nothing but screw up air/fuel ratios from what is essentially a vacuum leak. (BTW - have you checked the PCV valve for cleanliness; I hope it rattles easily)
#3. Northstar piston rings are forever. 200,000 mile examples still have the crosshatch marks in the grey iron sleeves.

Put the car up on a lift and rule out oil leaks - at the oil pan rail, the halfcase rail, and the oil filter adapter O-ring joint at the block.

It's entirely possible that you have valve stem seal problems - if the exhaust smokes when you idle for a while and then take off - it's valve stem seals. If it smokes after forced deceleration (as in: WOT endgame) then it's stuck piston rings and/or valve stem seals.

Now read up on the good ol' WOT - for starters, go up to the Cadillac Technical Archive in the black bar ^^^ and read the entire Archive, especially the section "Occasional full throttle operation is good for your engine".

VIPERRACING
03-23-10, 09:13 PM
Sub, as always thanks for all the info. The car has no leaks and it doesnt smoke at all when sitting at idle or cruising. A ton would mean about a quart every 300-400 miles.

Submariner409
03-23-10, 09:22 PM
A quart every 300 - 400; the exhaust pipe/tips must be black.

What oil are you running ?

Get a friend in another fast car and the two of you get outta town - have him/her follow at a respectable distance and run the snot out of your car - in daylight. Instruct the friend to note how and when smoke (if any) occurs. Both on accel and decel. That is a sure telltale of the conditions under which the engine uses oil.

You mentioned a "slightly rough idle". This can be caused by, at this point, anything from fouled plugs to bad wires......run the car for a smoke test first.

EDIT; Before you head out to do the stress test, dump a 20 oz. jug of Chevron TECHRON in the gas tank and fill up with premium Shell, Texaco, or Chevron.

VIPERRACING
03-23-10, 09:34 PM
will do and yes the exhaust pipes are black. Like I said, the car has never been driven hard. The oil cap is just a old school trick for venting the crank. I use non synthetic mobile clean 5000 5/30. I was actually thinking about putting 20/50 in it to see if it helps it from going through so much oil.

Ranger
03-23-10, 10:05 PM
Ranger or Sub, do you think the high speed decels will solve my problem or do I have to have the motor reringed?
The fact that you are using so much oil means that the cylinder walls and rings are WELL lubricated. Like Sub said, if you pulled the head you'd probably still see the factory hone pattern in the cylinder walls. Take it out and beat the hell out of it using the WOT procedure described.

I also drilled the oil cap so that it would help vent the crank. The oil cap is just a old school trick for venting the crank.
:tisk: This ain't an old school engine.

the car has never been driven hard.
And there in lies your problem. Drive it like you stole it.

VIPERRACING
03-23-10, 11:54 PM
ya the cylinder walls did look like new when I did the headgaskets on it. I couldnt believe it. How many pulls do I need to make & how often? Will I be able to tell while Im driving it if the rings get pulled back out? I know, stupid question but you guys(ranger&sub) seem to have all the right answers. Thanks again for all the help. You guys rock.

Submariner409
03-24-10, 11:01 AM
Do NOT put 20W-50 in a Northstar !!! "Thick" oils will NOT stop an oil burning issue, but they WILL cause excessive engine bearing wear, particularly after cold starts..

Find the mechanical problem and correct it. Head gaskets: Did you check the cam followers (lifters) for wear and "dishing" ?? Did a shop replace the valve stem seals ??

Your engine is spec'd for 10W-30 and that's what you should run, in whatever type and brand that floats your boat.

As far as the WOT procedure goes, don't unnecessarily flog the car, just work up to full throttle accelerations from a stop, stick in 2, go to 2-redline, flip your foot off the gas and let the engine pull the car back down to 10 mph. Do it again, drive a while, do it again. Just for grins, on a freeway or 55 mph highway, drop the stick into 3 and leave it there - let the engine wind at 3,000 - 3,500 for a while.

You may find, after all this high rpm fooling around, that the oil gets pretty dirty, caused by high oil flow and detergents slowly cleaning out the crankcase and guts. Change your oil and filter, using a high mileage synthetic blend 10W-30 and a WIX 51522 filter. Pre-fill the filter and fill the crankcase to halfway up the dipstick hashmark, NO MORE. The engine takes 7.5 quarts with filter; any more and it's overfilled and will rapidly throw off the extra half quart. DO NOT fill it or keep it at the top or MAX mark on the dipstick !

Ranger
03-24-10, 11:38 AM
How many pulls do I need to make & how often?
Hard to say. If you see "smoke" (carbon) behind you, do it again. Then once a month.

Will I be able to tell while Im driving it if the rings get pulled back out?
No. The only indication you'll have that the rings are freed up is that your oil consumption will drop.

VIPERRACING
03-27-10, 02:11 PM
Ranger & sub, you guys are the men of this site. Went out and performed the decel and started driving the car a little more aggressive and leaving it in 3rd while in town and the car seems to have a new found, smoother power. Now my damn stereo lcd screen decided to go out and my car smells like burnt wires. The funny thing is that the stereo still works perfectly but with no lcd read out. LOL, just my luck. Thanks again and Im pretty sure we will be talking soon. Tony.

Ranger
03-27-10, 03:40 PM
:thumbsup: They do not like to be babied.