PCA Forums

It's my Saturn too (Well, the fiancee's)

It's a 96 SC1 she bought last year (BEcause it was red, and had a sunroof. I said NO Hon, trust me, mid 90s Saturn = Crap. Chevy in general = Crap) but she didn't listen)

Anyway. After the started went out, the flywheel and a few other problems, it was running okish. Check engine light kept going on, bring it in, it's the o2 sensor. Replace it. Wait a week. Repeat, about 4 times.

Car only gets about 8mpg right now. (On a full tank, I can only go about 250 miles before I need to fuel up, somethings off here!).

From my youth as a mechanic, I can remember that an O2 sensor problem isn't always an O2 sensor problem. All it means is the o2 sensor is telling the computer it's getting either to much fuel, or not enough, and the computer goes "WHoa, calm down here o2 sensor, you've been telling me we're running lean now, but I'm giving it as much fuel as I can, and it isnt fixing it, so you must be broken - time to flip a code"

So it's about time I do some checks. When I get (if I get) a new job soon, I plan on a tuneup, and was wondering if any of you chevy guys could give me an idea of where to check.
I plan on pulling the plugs and checking for an even and clean burn, as well as seeing if I can get the injectors tested, but other then that, I'm not sure.

Oh, it also has an intermittent problem where it eats oil. I can go for, say, 5 months and the oil level is fine. Then one day I check and it's a quart low?! So that's another problem to look into as well.

Any help would be great here guys!

Things i would check with a fuel injected car that was getting 8 mpg

1. Timing- is your fuel coming out the tailpipes
2. cap rotor plugs and wires
3. MAP sensor- this sounds like a suspect, but i like to start off with the easy stuff and work my way up

Good Luck, I really havent had to many people talk to me about problems with there saturns, ther then then tensoner pulleys seem to die prematurely in them, and its quite a job to replace the damned things

On a full tank, I can only go about 250 miles before I need to fuel up, somethings off here!

that would mean the car has a 31+ gallon tank.

not that there isn't a problem with the mpg...but it's not quite THAT low.

they only have a 12 gallon gas tank !
i bet part of the problem is broken calulator
iv,ed had 2 saturns now and been really happy with them !
both were bought new do !
one was a 1999 sc1 3 door sport coupe - little small but was fun to drive !
and now we own a 2002 vue - and its great - not had a problem with it ~
other then the sun roof came off track or a bracket did but they fixed it like 1 hour !and it was only a month old at the time !

Do you have heavy soot in your tailpipe or a black exhaust? Either is a sign of a stuck injector allowing way too much fuel flow....

Ill look into that.. Im pretty sure there isnt any heavy soot in the tailpipe, Ill check when she gets home though - some good info here, thanks guys.

Hrmm, how do I check the MAP sensor to make sure its working properly, btw?

The MAP (Manifold Absolute Pressure - I think) sensor measures vacuum at the intake to help the computer make correct timing decisions. They almost all have three wires. One is 12v, one is ground, and the third (often the middle) is a signal output to the computer where the voltage changes according to manifold vacuum.

I have always tested these by using a hand vacuum pump like a Mighty-Vac to pull set values of vacuum while measuring the output of the signal wire with a digital voltmeter and then comparing what I get to a chart.

If you dont have a vacuum pump, but do have a vacuum guage, you can plumb the guage into the map sensor vac line and rev the engine to get different vacuum readings and then compare the outputs from your digital voltmeter to your specifications chart.

At the very least, you are going to need a digital voltmeter and a vac guage or vac pump.

Ok, I'll add that to my list of things to buy: A hand vaccuum pump.

The timing thing though, that has me wondering. hehe.

Damn car sounds like its low on oil, but when I check it, it's fine - so maybe it's timing is out of whack. And that's something beyond my expertise so while I can check timing, I'll have to take it to a shop for adjustment

what O2 sensor are you replacing? the one before or after the cat? you ever think that your cat might be plugged up? that will cause a car to wrok extra hard.

Clean your PCV valve, homey.

Larry

Which o2 sensor? I thought the saturn only had the one, before the cat. I could be wrong (I didn't actually check it) but it's been replaced like 4 times, so I assume it's not really my O2 sensor. A clogged cat is a possibility, that WOULD rob power and reduce fuel mileage, and is a very good cause I didn't think about it. I hope it's not that, as cat's are somewhat pricey.

I do plan on getting a fuel injector cleaning kit (If they make em for consumers). I don't know if you know what I'm talking about, but it's basically a can that connects to the fuel pump and pumps a cleaning fluid through the manifold and such instead of gas. You run the car till it cuts out, then remove the can and hook the fuel rail back up. I'll have to look into that, but we charged people something like 130$ to clean their system, hope it isnt that pricey to buy.

Cleaning out the PCV valve, I'll add that that to the list too.

Hopefully I can get this thing on track, as it used to be an ok runner, now though, well, we ARE trying to get rid of it and get a new car - but with me being basically unemployed and my credit down the tubes (No money = no ability to pay bills. Sidenote: I'm declaring bankruptcy once I land a full time job ) and her not making enough cash, well odds are I'll need to fix it. I appreciate all the input I'm getting though!

double check your computer calculations: you said that you can only go 250miles right and your running 8 mpg? that must be a aftermarket tank you got there!!

if its not to hard, remove the cat and look through it. if you cant see light its pluged. take a large object that will get in there and start breaking it out. once you have it hollowed out put it back on the car. your not supposed to do this... but its cheaper then replacing it.

i'm with pugsley on the Cat thing... i've hollowed 4 of them out... too damn expensive to replace and we don't have emission checks here yet so i'm not to worried about it...