Saturn sc2 2002
 

Cars are complex. Little changes can make a big difference and it may of for me.
So I was doing what little fixing I can do with my car. I had just replaced my front O2 Sensor. About two days later my engine starts shaking, which was not a surprise to me, I need new motor mounts.
The odd thing is when my check engine light stated to flash. Got the code (P0303) something about a misfire in my third cylinder. Read up on it, saw some big price tags if I let it fester for to long, so I tried to jump on it.
Of course it could be a million things, I went with what I was going to do anyways and what I could buy then and there. I got new spark plugs, wires, and coil packs. but the light persisted.

Does anyone think it at all possible that the shaking of the engine is throwing the error?
Or is another problem just cropping up?
Or is it my O2 sensor.

It didn't go away after I installed the new spark plugs or coil packs.
I just put on the top motor mount and although the engine is smooth as a baby's bum now, the error is still there.

I'm trying all the small or cheap fixes right now, cause it gets expensive fast.

I took off my valve cover and my seal is trash. it's leaking (although a little) oil into my spark plug er, "holes".
So that could be the and/or a problem.

I also read up that it could be my intake, or fuel injectors, but I'm a computer guy, not a car guy, so I can only google so fast about locations and how to's, you know.

p.s. The computer is shutting down the cylinder? That's good to know. Cause a new converter is a fair bit of money.

Oil leaking down the tubes where the spark plugs are installed can, if it builds up high enough, get wicked up between the spark plug boot and the spark plug, "shorting" the spark before it ever get to the end of the plug. Therefore not firing in the cylinder, and the car's ignition system detects it as a cylinder specific misfire. Check your old #3 wire's (2nd longest) boot end for swelling from oil absorption and evidence of oil presence.

As for plugs, use should be using the stock plain old copper plugs, not anything else. No platinum, iridium quintuple electrode byzantium impregnated plugs. Unless you want to chase misfires that are a direct result of using the wrong plugs for this engine.

What rpm does it idle at at operating temp? Manual or Automatic?

Don't change more than one thing at a time while troubleshooting. You lose your ability to draw direct conclusions from the change.

Automatic.
It idles at about 800rpm

700-800 rpm idle for DOHC A/T, so OK there; likely no vac/intake manifold leaks,
How many miles on the car?.
What prompted you to replace your front 02? If it was a code, which one (Pxxxx format please)?

For clarification:
1) Do you ever have ONLY a solid SES light when the car is running? When? (pre O2 replacement, post O2 replacement, both? neither?)
2) Is the SES light always blinking while the car is running?(Did that start before or after you replaced the O2 sensor?)

A) What front O2 sensor did you use as the replacement (brand and part number--no I'm not implying you used the wrong one, there are some known to be happy in these engines, and others, well......)
B) Did you have the P0303 before replacing the front O2?
C) Did the engine start shaking right after you replaced the front O2? Or was there a window of time with new plugs, wires, coil packs and new O2 sensor where the SES was not lit and the engine ran smoothly..? Did you refill your gas tank after the O2 replacement and before the shaking?

Not trying to play 20 questions; just like to have all the pertinent info up front so we can troubleshoot down the right path.

Remove the spark plug boots from the plugs and make surf there is no oil still collecting in the spark plug wells.

Miles: About 130k (130,000)

The SES light was solid with a "bank 1 Sensor 1" code
After changing the O2 Sensor with (Part# 11027 Bosch Oxygen Sensor) it ran smooth for a couple days before it started to shake.

At this point it has a flashing SES light with the p0303 code. It flashes sometimes, usually around 40-45 mph it seems. It's either solid or flashing.

After changing my PVC valve and hoses and the head valve gasket, I have found no more oil in my spark plug wells. No more oil specifically, I still have to remove the little that was into there from before though.

Sounds about exactly the mileage that the O2 sensors in the front give up the ghost. I find Bosch sensors to work like crap in my Saturn's. I use the Denso sensor that is equivalent to the AC Delco sensor which in fact is a rebranded Denso or may actually say dancing on the outside. You still have not indicated what type of plugs you are using. If you do not have the stock NGK good old 5643 copper plugs, go spend $6 and put them in. And get that oil out of the spark plug Wells. And be sure to soak all the oil out from inside the boot where the plug connects.

I assume you meant valve cover gasket not head gasket.

And and for the record, that behavior is exactly what Bosch front oxygen sensors do in my cars. That's why I run the densos.

Yeah, Valve cover gasket.

I got NGK copper plugs.

Should I just take the cover off and stuff a microfiber rag down the wells to get the oil out?

I'm going to check the fuel injectors to make sure they aren't clogged or anything and get a new O2 sensor.

Hopefully it will fix the problem, cause besides this, all the stuff I've done to my car has made it buttery smooth in other areas. Can't wait to see how it runs after I fix this.

If the cylinder misfires enough times it will set the SES on solid and store the P0303.
Flashing SES indicates active misfiring. The fact that it doesn't flash until 45mph on the highway may indeed indicate a fuel restriction.

Before pulling the rail and injectors, check the wiring at the connector for the injector for #3 to rule out the possibility of it being an electrical issue.
Also, before pulling:

On an ice-cold engine, pull all the plugs and make sure they are dry down by the spark gap. Reinstall. Pull the Fuel injector fuse. Crank the engine three or four times. It should not start.
Remove the plugs one at a time. All should be dry w fuel injectors disabled. If #3 is suddenly wet with fuel, the #3 injector is likely not closing all the way, leaking into the cyl when it's supposed to be closed.

It might be sticking closed at different rpm/speeds, leading to the misfire code since nothing combusts in the cyl if there is no charge fed into it. Both are

This can POTENTIALLY be addressed by

Going to the parts store and getting 2 bottles of Techron brand fuel system treatment. It is not inexpensive but based on personal experience and that of others on this forum, it works for cleaning out the injectors.

Drive your gas level down just below a quarter, then add Techron to the tank and fill with 93 Octane of a brand name gas like BP, Sunoco, etc. Between the fuel system cleaners in the higher octane brand name gas and the Techron, if your injectors are less than clear, you should notice a difference between the start of the tank and the end. Repeat with a second Techron and 93 tank if the code persists.



I would think the oil in the plug well would drain into the cyl if the plug was removed. Whatever you do, do NOT try to wick the oil up with the plug removed unless you are 400% positive 0 debris will fall into the spark plug hole while doing so.

I would not think you'd need to pull the valve cover gasket to do this, but the wells are indeed pretty deep,

There is also the possibility that the PCM is seeing a weaker combustion event in #2 than in the other cyls, and is considering it a misfire under certain condiions. If so, we can track down why.
But let's clean out the oil and try that first before going on a wild good chase.

Spark plug wells dry as a bone ✓
NGK Copper Plugs ✓
New O2 Sensor ✓
All New mounts ✓
Valve cover gasket changed out ✓

It really is running better than I've ever seen it, and this were all problems that needed to be fixed, but none have been the problem yet.

The Engine still shakes (just much less with all new mounts), there is a gas smell, the misfire code (solid and flashing) still plagues me, and a liquid almost like water is coming out of my tail pipe.
It is idling at 800-900, moving back and forth between them. The idle and shaking become worse after it reaches operating temp. If I give it some gas the shaking goes away and as I am accelerating, I don't know if the ideal leaves too.

I have no checked on the injectors yet (waiting for another long weekend), though I have done the Techron and 93 Octane to try and clean the injectors if there is a problem with them. (My ghetto screw driver stethoscope doesn't hear anything wrong with the injectors)

It seems the more I fix it, the more problems crop up. I swear this car will be amazing once I'm done.

Have you checked your PCV valve for proper operation? You've addressed some of the issues and seen improvement. Maybe a new PCV valve would help, especially if that's the original. You might also try looking for a vacuum leak with the idle being funky.

Water under the bridge but I hope you used AC Delco Mount for the upper torque axis mount; aftermarket ones just don't cut it in comparison. Obviously, your full swap of mounts helped but is not the root o the issue so let's put on back burner.

Prior to this, you indicated it was idling at 800 rpm. This is the high side of a DOHC A/T car.
You now indicate the idle is wandering between 800 and 900. This is too high and indeed points at the possibility of a vacuum leak (including at the intake manifold around # 2). It also may be that your idle air control valve is gunked up or not functioning correctly. There is a little servo motor in there that modifies the size of an opening through which air passes when the car is near idle rpm to smooth out the performance.

I don't see a throttle body cleaning listed as having being performed. I'd recommend that next.

Remove the air intake ducting at the throttle body after unclipping the battery box lid and disconnecting the line from the valve cover to the air ducting. Actually inspect the ends carefully as these deteriorate easily.
Use throttle body/intake cleaner (NOT CHOKE CLEANER) for the cleaning. Some people like to remove the throttle body entirely; I never have, I just clean it often enough on the car that proper operation is not an issue.

Put a rag underneath the face of the throttle body to catch crap that drains back out. With the engine running, put your hand on the spring loaded throttle control cable mechanism. Rev the engine a bit and start spraying into the throttle body. You will need to work the throttle by hand to keep the engine from stalling. A quickly acquired skill. If it stalls, no big deal -- it will just fight on the next start but WILL start. MIGHT have to feather the pedal but save that as a last resort.. Avoid spraying too much at once to avoid stalling. Once you are confident on the restarting, and all cleaner has burned in the cyls, shut engine off. Hold the throttle plate open and liberally spray the back of the throttle plate, letting it soak a bit between dousings. be sure to do around the very edges of the plate, as any buildup here will restrict throttle plate movement. Tough debris can be removed with a soft toothbrush soaked in the cleaner. The back of the throttle plate should be clean when you are done with it.

The little opening at the bottom of the throttle body face leads to the IAC valve (Idle air control). As stated before, if this is gunked up it will not move/actuate correctly and therefore not deliver the proper amount of air near idle for the engine to run smoothly. Douse the hole and let the crap run back out onto the rag. Wait a few minutes to let it soak a bit, then repeat. Repeat till it rinses back clean.

Hopefully most of the cleaner will have back drained onto the rag. You will struggle to re start he car and may have rto pedal it. Just don't crank for more than 5 sec at a time so you don't kill your starter or run down the battery excessively.

Once fired back up, spray the IAC to get cleaner sucked into it, At idle it will be feeding air into the throttle body, so hitting it with the cleaner will lead to an instant stall if you aren't ready to catch it with the throttle. The IAC can be removed for cleaning. I have never found the need to do so.

I predict that a good bit of the idle wandering should be addressed and it should idle when warmed up arond 700-800 prm IF there are no vac leaks. If nothing else I expect the idle wandering to be addressed if the IAC is suficiently clean and functioning properly.

Clear the codes and take it for a drive, and note
-- how long it takes the SES to turn on solid and at what speed if on the throttle
-- exactly when the SES blinks. Speed related, throttle position related (important), only when on throttle, etc.....

Does the SES blink, then go solid, or go solid, then blink at different times?

After a lot of testing and thinking I have found that it's kind of all over the place. The flashing happens more often than not while I'm on a hill, around 2 RPM or approaching 45 MPH.
The hill (slight, nothing steep) next to my house, I can recreate a misfire every time doing 53MPH at 3.2RPM. What that tells you, I don't know. I also changed the problem cylinder fuel injector, which did nothing for the light.

What I do know:
I have a leak in my intake manifold (Cause that cause the light, no clue.)
I seem to run low on oil in between changes.
If I sit stopped, on, in drive, for a while, I will sometimes get little puffs of smoke out of my exhaust, with a blue tint (Which means I'm burning oil, if I remember correctly). This happens rarely, but seems to me to still be something of possible importance.
Sometimes, when I go to speed up quickly, the car will 'jerk'. Like it just jumped forwards.

I currently set at a wandering idle of 700 to 800 rpm.

Be sides all that, it runs good. I can take hills nicely. It doesn't feel like it has no power. I am awful stumped at what the problem could be.

It seems simple in my head. A misfire means it has to do with something in the four stages.
Something with the fuel, spark, air, or exhaust. Something that is going wrong to cause the misfire. To much fuel, not enough. I think I'd get a code for running to rich if it was anything to do with the air (still, I don't know).
But I'm at a lose to figure it out.

I like the car, and selling it isn't one of my options. Anything else I got would have it's own problems anyways, so I'd be at square one with a different car.

Where is the intake manifold leak? A vacuum leak near #2 will let unmetered air into the cyl, messing up the air/fuel mix, and causing a misfire.
You are burning oil, either through leaking valve guide seals or oil getting past the oil control rings. To get blue smoke out of the tailpipe it must be burning a huge amount of oil or you have poisoned the catcon from all the oil going through. Pulling plugs after use should revel at least 1 oil soaked plug.

Would have been a lot easier had you divulged above info at the start but water under the bridge

Welp, I'm taking the head off because there are really only four things it can be and they are under the head. Thank you for all your help, when I figure out which thing is the problem I'll post it so in case anyone else is having the same issue, they can figure it out faster and cheaper than me (Though I don't regret fixing everything I've done so far).

If all else fails, it may be a piston ring, if so, I'm not sure what to do. That is an expensive fix, and not one I have the tools or time to do myself. (I guess I could always get a rebuilt engine)

Before diving in.....

Do a compression check (remember wide open throttle). Autozone Loan a tool if you need to.

Get up to operating temp. Turn off.
Gingerly remove all 4 plugs before starting.
Remember to pull fuel injector fuse under the hood.

If the test reveals super low compression on 2 compared to the others, it's quite often a partially burned exhaust valve.on the DOHCs.
Rare for 130K, though.

Unlikely to be head gasket as you have not mentioned the milkshake or overheating issues.

Did you happen to spin the engine by hand when you had the valve cover off to ensure you don't have a marginal lifter?

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HOW low does the oil get between changes and how many miles is that?
Has it ever gotten 2 quarts or more down?

Did you ever swap out the Bosch O2 for a Denso or even the bad one? Would be interesting to see if the idle still wanders with the old defective one. It did not wander before replacement.
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The wandering idle to me sounds as though it is either
1) an A/F mix issue where the feedback from the front O2 is going rich/lean/rich/lean/rich etc indefinitely or
2) the IAC is not operating correctly, and there is either too much or not enough air getting through. This would end up skewing the A/F ratio, the front O2 would see it in the exhaust,.....
To be honest, I do not know how the IAC position is controlled. Via the PCM of course.

But when the A/F mix gets funky, if the PCM were to mess with both air and fuel at the same time, I'd think that would be a self-fulfilling failure unless it resets the IAC based on assumed airflow and changes the fuel.

I have not turned it by hand to check that but I can next time I have the chance.

it's the Standard Oil Change mileage so every 3000 miles and I don't know the exact amount I go under but it's low enough for the check engine oil light to come on, so it's quite an amount.

all I know is I have the wandering idle, the sputtering noise in the exhaust which from what I know is usually a Telltale sign of a intake leak somewhere, and the shaking of the engine with the occasional small plumes of blue smoke out the tailpipe. And there are probably 10 different things it could be and it's frustrating because I keep trying and narrowing down the options and it keeps becoming a more complicated and more problematic fix that'll have to do.

but I'm willing to do anything I'm physically capable of doing which is pretty much anything that doesn't involve lifting the engine out or mounting it because I just don't have those tools.

Oiy crap.

The Oil WARNING light comes on when the oil pressure in the engine is insufficient to properly lubricate the engine.
The light can be triggered by oil pump failure.
It can be triggered by a bad sending unit (happens).
Based on your description of losing oil, It is much more likely in your case being triggered by an oil level so low that there isn't enough to keep up with the pump.

This is a serious issue, as it does not take long for the metal on metal contact to damage the engine internals to the point of failure or engine seizing.

If this happens repeatedly, it is likely only a matter of time before failure.

It's only a 4 qt (oil) car. I'm pretty sure the oil light doesn't come on until less than 1 quart remains - and that 1 quart can't feed the pump enough to maintain proper oil pressure,

Was the oil light on before you developed the misfire?.
Do you drive around with the oil light on?
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Please do the compression test before you disassemble the head. If you have a serious compression drop in #2, it may be damage related to the lack of oil.
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I think you may be putting a lot of effort into a seriously damaged engine.
If it is not leaking oil and you are burning that much oil, the oil control rings will need replacing.
You'd want to hone the cylinders and then use oversize pistons and rings (oil control and compression).
Since the head will already be off, the head will need a valve job and the valve guide seals replaced at a minimum. Might as well put in new lifters and replace any valves showing signs of abuse.
You'll need a new cat from all that oil.

The list goes on.......

Don't get me wrong -- I'm not hoping this is the case -- but if it is, I'm trying to help you see what will be involved to fix the known issues.
If you have the engine open, it does not make sense to do just bottom or just top end in these cars, because the oil burning issues arise from the bottom end and top end.
You may just want to pass on repairs and drive it till it fails. But at least keep the oil up or it won't last very long.

The oil light came before the misfire.
I noticed blue tinted smoke out of the tail pipe.
I was told by the people who do my oil changes, that I may be burning oil. So I started checking it and keeping extra oil in my car.(It doesn't lose oil at the same rate. Some times the light never comes on, other times it comes on right before I need the change, or other times it may come on quite a time before I need the change.)
As I looked into what could be wrong, I noticed a small oil leak. It wasn't dripping around the pan, so I checked where it could be.
I took the valve cover off and saw that the gasket was trashed, and there was just the tiniest bit of oil on one of my spark plugs, so I replaced it, and them.
Seemed to stop the leak (At least I never noticed it after that)
While in the mood, I decided to take on my check engine light (Which was the O2 Censor)
Changed that, and than is when the misfire begun, and the shaking. (I later changed the O2 Censor to the model you suggested)
After that I jumped on these forums and everything else is in this thread.

I don't have a lot of money, and a car is something I need to do all my daily activities. So there in lays the problem. If I try to sell this car, and save up money, I'll only get a new car with new problems (which could be smaller problems, or things I can fix before that because real problems). If I try to fix this one, and have to do what you think, it'll cost me a lot of money just in parts, and the labor would be crazy for me (Computer guy, not really a mechanic). I could always buy a rebuild engine, they seem about as expensive as the parts to fix it myself, and way cheaper than having a shop fix it; only problem there is getting it into my car.

I'm going to spend quite a bit of money no matter what I do, so at this point, I guess it's just about figuring out which is the best uses of that money.
I do like my car, being my first actually car I've owned, but I do like getting from A to B without the fear of exploding.

See/hear for yourself.

The shaking goes away when I accelerate.

That sounds like a misfire to me. BUT, I'm NOT an ASE Certified Master Mechanic or do I claim to be a mechanic at all. I've just kept a multitude of cars that I have owned over the past 45 years running pretty efficiently. Since you said it's pretty much a problem with the O2 sensor replacement, that's what I'd start with. There are proper and improper ways to change out an O2 sensor. I won't get into them because of the statement about my not being a mechanic. Do a google search and you'll find the proper procedure for that. Oh, and to add to it, the DOHC is well known to burn/use some oil between changes. Don't be overly concerned about that. You're doing the right thing by having extra oil on hand and keeping a regular check on it. Props to you for that.

What were the results of the compression test on that cyl?

Okay, so, we had two options, ****ed and totally ****ed. I think my car is a bit of an over achiever in this sense, cause I think I'm both.

I have no clue how the compression went down, for the wet test, doesn't make much sense to me.
Nevertheless, I have some problems here. Cylinder number 3 has a hole in the piston, the valve seat could be broken, or the valve is broke (has a hole in it, or is missing a part of it (Which may explain the gas smell if it's an intake valve)), cause there is no compression. Again, I don't know what lower compression means on wet (Don't think that's a thing).

The compression for the cylinders that had any, built fine, I think. Jumping 15 psi each stroke, but I don't know if that's good or not.

From what I am reading about, I now better understand my problem, but it is still up in the air the exact problem. I could have a hole in the piston, the valve, or the intake/exhaust at that cylinder, which would give me no compression. Which really, doesn't help me, cause my problem was already going to be the pistons, valves, intake/exhaust, or head gasket, so I'm going no where fast.

The book goes over a whole list of things I need to do, but some of them I couldn't see a reason for.
When removing the head. I am to remove, the valve cover, intake manifold, exhaust manifold, drain oil and coolant, detach and move out of the way the power steering, remove belt, timing cover and chain, of course negative off battery, and than the alternator, and some sites said the oil pan maybe.

Mainly the last two seem weird to me. It didn't seem right. When I was under the car last, it didn't look like the head was even close to the alternator. The alternator didn't seem to be attached to the timing cover either, same with the oil pan, so I'm not sure why I'd be removing them.

Also, depending oh what it is, what is the generally option of PickaPart for parts? I mean, it can't be worse than what I have right now, right haha.

Everything looks okay.

One thing looked burnt, and none of the valve springs had any give, so, at least they still worked.

Also, I re-did my compression test, this time with the long style bit, and got much better results on the other three cylinders. (110, 105, 0, 115)
So, at that's nice.

Those readings seem extremely low for a dohc s series.

Did you remember to
Pull all plugs
Pull fuel injector fuse
Hold the throttle wide open while cranking the engine?

I think I grabbed the fuel pump fuse, but should be the same effect, right?

As long as there is no fuel in the cylinders for the test. There may have been residual fuel pressure in the line that could have released itself through the injectors. MIGHT have something to do with the bizarre wet test results though I haven't put any effort into figuring how.

A hole in the Piston, especially from a valve ejecting itself, would lead to a huge smoke cloud from oil burning in the cat. You do not have this. DOHCs tend to burn up exhaust valves, and since the valve guide seals eventually leak oil into the cylinder, you end up with much less oil entering the cylinder. You will ultimately find out when you pull the head.

If those compression values are correct, your rings are likely worn. For perspective, the service limit stated by Saturn is 195 psi. You might want to repeat the compression test with the fuel injector fuse pulled.

I finally took the head off.

The head gasket on there was, well, take a look. As well, I had no one, but two, in two different cylinders, these messed up guys (and one was in the misfire cylinder.)
https://cimg4.ibsrv.net/gimg/www.sat...612a8a3fb0.jpgLooks like they work perfecty
https://cimg7.ibsrv.net/gimg/www.sat...873639b6a2.jpgOEM (Original equipment mangled)
I'm going to go out on a limb here and say I found my problem haha.
And the cheery on top is that my timing chain guide are also broke. (Which could also be reason for my problems.)
So, my car had basically all of the problems.

Luckily the Cylinder walls look nice, the pistons are great (little dirty, but great), I will have to change the valve stem seals (Cause always change seals), but everything else looks great.
This car is going to sign when I'm done with it.

Should I change the valves though. They seem to get expensive quite fast. So if I don't have to get new ones, my wallet would be happy. Of course I need two new ones to replace the broken ones.
The other exhaust are all crusted with crap, but the intake look fine (if not a bit dirty).

I have to agree with Andy if you're planning on keeping the car. No point in half-assing a job when you're that far into it already. Now, if you're not going to keep it, then pass on the ring job, but definitely replace all of the valves. A new owner at least deserves that.