Hi, I have an SL-2, and we have been having major problems with it. The service engine light has been on for about a year, and about three weeks ago started to blink. When tested at Auto Zone, it came up with Cylinder 3 Misfire, Camshaft Sensor and Oxygen Sensor. So far, we have replaced on this car: the spark plugs and wires (and made sure that the plugs were timed correctly), the camshaft sensor, the EGR valve, the oxygen sensor (before the catalytic convertor), the coil pack attached to cylinder 3 and the engine coolant sensor. I have an appointment at the Saturn dealership in Binghamton Friday, but don't want to waste my money, since we don't have much. Can anyone give me any suggestions for any other thing that can be causing a misfire? We are going through a ton of gas, like 200 miles to a full tank, when it used to go 400. And the only way to describe the preformance is "chugging". Please, can anyone help me?? Thanks.

 

Did you check the # 3 injector?

 

check injector

 

We took it to the dealer where we bought it, they ran the diagnostics test, the fuel system and electrical system came up fine. They diagnosed it as needing an upper valve replacement, or since they have to rip half the motor apart to get to the valves, a new motor. So, we're waiting for our tax return to come back so we can fork over $2,000 for them to fix it. I wish we could get a new car, but there's no way.

 

you can get a good low mileage saturn engine from a wrecking yard for $350 to $500

 

Before you shell out the big bucks, pull the spark plugs and take a look at them. Is #3 fouled up or is it clean? Next do a compression test on #3. Compare it to your other cylinders. Are they all about same? If you're around or above 100 psi, it should be firing ok. If you've got low compression on #3 it's more likely that the rings are seized. I've heard that if you remove the plugs and dump some Marvel Mystery Oil into the cylinders for 24 hour soak, this will free up seized rings. Of course you have to deal with running all of the MMO out of the engine after the soak. My 95 has 213K miles on the original engine which has never been apart. It gets 30+ mpg. I change the oil every 3k. MMO oil flush every 15k. If you check and change you oil religiously, these engines are good forever.

 

At Saturn, they checked all four cylinders and there is no compression to cylinder 3. The plugs are brand new, and have been checked (I believe more than twice) and they said the problem is coming from the valves. I forwarded your message (stevestar) to my husband, who is the one who has been working on the car. We'll see. At the present time, we're waiting for our tax return before we can do anything. I'm apprehensive about taking it to Saturn, I don't want to be overcharged. But at the same time, there's no sense fixing the valves when you have to rip apart the motor, and then maybe something else is wrong after the valves are fixed. I tend to think it may be simpler to just replace the motor, the problem is with the cost of labor.

 

For $2.00 you can do the MMO soak on #3. The dealer is halfright, rings or valves. Valves beingless likely the culprit. Unless you got a turbo charged race engine, it's pretty hard to burn a valve. Now if you haven't been changing your oil and keeping it topped off, it's easy to wear down the rings and cylinder walls. I've been told that Saturns are notorious for seized rings if one doesn't viciously keep on top of the oil maintenance. How old and how many miles on your engine?


Here's another thought. If #3 has been running crappy for more than a year, the valves themselvescould be okbut the valve seats could befouled with carbon. Try this before giving up on your engine. Pull #3 plug, hand roll the engine over until #3 is at the bottom the stroke. You can use a coat hanger to feel down inside the cylinder to see when it bottoms out. Fill up #3 with MMO. If it just drains out, you got a ring problem. If after a couple hours, if the MMO level hasn't dropped, you can try to save yourself a valve job by re-installing the plug and rolling the engine up just a little. No more than a1/2 stroke. This will amerce the valves and seats in MMO. Let in sit for 24hrs. The next day, pull the plug and clean it up. Try to get out as much of the MMO as you can, pull the catalytic converter before firing up the engine. Yes, it's going to smoke and you may need a new O2 sensor when your done. But this could save some big bucks in thelong run. Once you've burned off the MMO, change your oil inthe nextcouple a days, then again a week later.The MMO will thin it out your oil considerably.

 

I am a stickler about checking the oil, which I do every single week, and keep on top of changing it. I am praying its not a valve problem, but who knows. Saturn said on the sheet my husband brought home "further testing needed, get inside motor and inspect valves and other problem areas", so they're not even sure it is a valve. I forwarded my husband your responses, I'll see what he says. I love my car, don't want to get rid of it, but can't keep dumping money into it. We need a new oxygen sensor anyway, ours has been replaced, but it needs it again. Thanks!!