Help my FE
 

So, I have a 1998 Saturn SL1 I here of all these other Saturn vehicles getting way better MPG than I am getting. Most of my driving is city, probably about 90% and the major drive to and from work is a 5 mile drive. At the moment I am struggling to get 25MPG it is completely stock and no modifications. I want to get a new t-stat but not sure what to get to get or where to get it and also maybe a new O2 sensor but not sure if that is mandatory. Anyways any help from fellow Saturn owners or any owners would be great, lets get up there in the 30?s atleast? :D

-Z

Welcome to gas savers!

I don't own a saturn but start with the basics, check and make sure all your tires are inflated to max psi or higher. make sure air filter is clean. Your right you should be getting better mpg, hopefully we can help.

Zvolen, please do enter your vehicle information in garage so we can know more about you and your car. there are a few saturn owners here and i'm sure they will help you out. you can also go check out the 2 threads there are at the top on this forum and they'll help you get started.

My mom's 1996 SL2 was getting crappy mileage and also leaking oil from the valve/cam cover. In that case, the cam cover gasket was replaced, new plugs and wires (oil fouled out the plugs and wires). No oil leaks and much, much better mileage. I can't quote her actual MPG. She just knows that she can go more days between fill-ups now. If you're not already a member of www.saturnfans.com, go sign up and search the forums for poor gas mileage. Much talk about the engine coolant temperature sensor (ECTS) going bad on pre-2000 Saturns. Also, change out the PCV valve if that hasn't been recently replaced. And only use a Saturn PCV. Autozone and the like are crap for Saturn PCV valves. Forum postings by "Wolfman" are very informative. One more thing, city driving, 5 mile drives to work yield low MPG. My 2002 SL2 gets 17MPG on my 2-mile drive to work! 40+ on the freeway makes up for that though.

Welcome to GasSavers! You didn't mention whether you have an automatic or a manual transmission. If you have a manual there are many more options for maximizing FE. If you have 100K+ on the car and it still has the original O2 sensor, It's probably a good idea to replace it. They aren't cheap so if $'s are a real issue I'd do the front one first since it is the one that determines fuel mixture. It's also the easiest to replace and only takes about 5 minutes. For a t-stat I'd go with a 195. The stock one is 185F but the hotter one will give better FE. I got mine from Advance Auto. As mentioned above, the ETCS is an important sensor when it comes to FE. You want one with a brass tip. The reason they went bad was because the old sensors had a plastic tip and they tended to crack with age. You may have to go to Saturn to find an ECTS with a brass tip though. I couldn't find any at the local parts stores. Any other questions, PM me. I have a complete set of Saturn factory service manuals that I can look things up in.

Zvolen -

Welcome to the forum! Is the SL1 a stickshift or an automatic? The EPA MPG stats assume 55% city and 45% freeway driving. For me, I am probably 75% freeway driving, so that is biasing my overall MPG stats in favor of high MPG.

I went to a NAPA parts store and got this thermostat :

192-195 Coolant Thermostat (Napa Part #THM268)

It was under $20. You might also need to pay an extra buck for the correct seal/washer. I don't think the one that comes with it is the right size (my mechanic couldn't use the one that came with it).

When you drive, is your coolant temperature on the "1/4" line, aka the first line? When you get the hotter thermostat, the coolant temperature will be somewhere between the 1/4 and 1/2 line.

Go to ebay and see if you can find a ScanGauge for cheap. That is going to make a big difference in how you drive.

I would hold off on the 02 sensor because it costs $50 or more. You may need a new ECTS (Engine Coolant Temperature Sensor) because you might have the one with the "hard plastic" housing. This hard plastic housing is exposed to the coolant and wears out, fouling the readings from the sensor. You can go to a Saturn dealer and buy one with the brass (or copper?) cover for under $20. You might already have the brass sensor installed. I don't know what year they switched to the brass sensor in all models. Do you have the maintenance records of the car? The dealer may have put it in as part of a regular maintenance upgrade. I just did this recently because I didn't know, but it turns out that I already hade the "good" sensor, so it must have been fixed by the dealer.

Rhetorical Question : Why the plastic cover temperature sensor? I think this is the same temperature sensor part # that is used for the IAT (Input Air Temperature) sensor. You can see what the plastic cover looks like by looking at the sensor that is in the "outside air intake tube" that is attached to the airbox. I think they were just using the same sensor in both locations.

Everything davidjh72 and other have said is right on. You might be interested in a block heater to avoid cold engine startups (is this true everywhere or just colder climes?). If you have a stickshift, then you can take advantage of coasting in neutral or EOC (engine-off-coasting) depending on your circumstances. If you have a 5 mile route, then consider looking for an alternate "optimum" route that doesn't use as much gas.

I originally trolled around in the saturnfans forum for a lonnnngggg time to learn about my car, and that led me here to GasSavers. The only problem with the saturnfans forum is that they seem to be having bandwidth problems. You have to be patient, but it's worth the wait.

CarloSW2

Thanks for all the helpful and quick replies I will try to answer some of the questions you guys brought up.

@cfg83 – My Saturn is an automatic transmission, I know-I know but the wife doesn’t drive stick shift, although she rarely drives this vehicle. Yes, my temperature is usually right at the ¼ mark if not below rarely gets above that line. I know these vehicles perform better in the hotter range and I was hoping to get the hotter t-stat. I did recently change my ECTS to the new brass tip, I also changed the plastic connector as it was also corroded that helped a lot and got me a few MPG’s.

@diamondlarry – Thanks, as stated above its an automatic transmission and it has 117K miles on it I purchased with about 115K and have had it for a few months and just not getting in to other aspects of the car. Also, sent you a PM.

@Davidjh72 – My car doesn’t leak any oil as I have routinely checked it as I hear that is a problem with these vehicles if you don’t. I have already replaced the ECTS with the new brass tip as well as put SeaFoam and changed the plugs/wires. I did happen to find saturnfans.com which is how I found this site where I have lurked for a few months while familiarizing myself with my car and now I hope to change my FE with the summer months coming. I figured straight city driving isn’t a good condition to get maxed FE.

@LXMike – I thought I had entered my information in, what other type information should I put it as I do not have any mods or anything. Unless the repairs I have done are considered that, I also plan to update my gaslog as I have been tracking that since day 1, hopefully that helps.

@Elf – That was actually one of the first things I did was properly inflate my tires to what the inside of the door indicates, slightly over at 35PSI and the air filter is clean, but maybe that is one of the things I should replace as it as yet to be done.


If you have any other questions or need more information just let me know I hope this helps those that had the questions and that I can get the MPG up to save some more money and the air at the same time. Thanks again for the replies.

-Z


**Edit**
I also heard alot about IAT sensor would this also be a good thing to change?

You did not say your location. A EBH (engine block heater) is the only way to go especially if your up north. Having such a short commute it's really hard to get good numbers with an automatic. Picking the right route is critical. Good Luck and keep us posted. If you go to garage tab you can fill out the info on your ride and track fuel usage. Welcome

Sorry, I live in sunny california in the central valley. I am sure I won't have much of a problem with the temperature once summer comes as it gets fairly warm here. Also, I did the gas log but it doesn't show up with the EPA in my signature I am sure I have to do something for that to happen just don't know what. I hope we can get these numbers up :) I will look into a scanguage but it may be a month or so.

After hearing all that. I say it is time to brush up on your driving methods. Driving like a grandma generally helps :D and look ahead to anticipate slowdowns or stop situations.

I missed this. Short trips do affect the mpg negatively, but with practice I think you should be in 30s.

kickflipjr -

Ehhh, Sonny, what's that you're trying to say :confused: ?

When I was a little kid, I think that my Dad accidently taught me good FE driving habits. He had a game called "never stop". When he would drive, he would try to time his approach to stoplights by slowing down early. If he "won", he would never have to stop the car. He used to be an engineer, so I think he was applying "conservation of momentum" and efficiency and stuff. I picked up that habit over 20 years ago. Good habit.

CarloSW2

I've never driven an auto saturn, but. I would try to keep the convertor locked up as much as possible when driving in town.

Sadly, I thought I was driving like a grandma. Which brings up a question when getting up to speed should I slowly get to the speed or speed up to get there then coast from then on to maintain that speed?

Yes, I am sure this doesn't help hopefully with the summer months coming I can increase that or maybe even ride the bike to work. I have looked for a alternate route but its basically a straight shot down one main street. I am not sure at what speed would be best for FE. Maybe a scanguage is in the near future.

Silly question, but how would I go about doing that?

Not a silly question at all -- it's a very complex system.

I recall having a rental SL-Automatic a couple of years ago, and noticed that the TC engaged at funny points, such as full lockup in 2nd gear, unlock-shift to 3rd-relock, same for final/4th (I think that the TC has to unlock to shift gears).

To keep the converter locked-up requires a light touch on the throttle and "bleeding-off" of the throttle when you slow down to keep it going (or lightly remove pressure from the throttle) -- conversely too much throttle unlocks it, and complete throttle lift unlocks it. Finally (other conditions aside), slowing speeds change the lock dynamic -- so it unlocks as you slow below a certain speed.

Regarding the automatic: I say bravo that you're not giving up on it because it simply has this transmission design. People will try to convince you to swap a manual in there, but if you don't want to for a variety of reasons, that's completely reasonable. The challenge lies in improving the FE with what ya got.

If you're into the deep constructs of how your vehicle operates, find a shop manual. It will show the schematic for TC lockup conditions from a variety of sensors and conditions (granted, if you're not an engineer, it may be confusing -- I can vouch for that).

RH77

I see, I will check out a manual for a more detailed answer hopefully I could understand it.

My intentions are to go to extreme and have more expenses just to get better mileage but to supple do all that i can with my current setup. Well I guess I will go to semi extreme measures.. :) I like that car that I have and expect it to last a long time that will balance out some of the FE I miss out on.

Zvolen -

Egg-zactly. Between here and saturnfans.com, you will learn everything you need to know about your Saturn. I wouldn't be comfortable EOC'ing in an automatic unless I was a grease monkey. Seems too risky to me. And if I had the skills to fix the tranny, then I would switch it for a stick anyway.

If I had a 5 mile commute, I would look into an alternate route, if possible. Let's say that for the point of argument, you get 25 MPG going 5 miles. That would be 5/25 = 1/5 = .20 gallons of gas. If you found a 6 mile route that got you 36 MPG, that would be 6/36 = 1/6 = .16 gallons of gas. The extra mile would actually save gas!

Remember that a 5 mile commute is also good for the environment!

CarloSW2

Been looking for an alternate route but like I previously stated its pretty much a straight shot, not many other options and if so just as bad. I actually have been planning to ride my bike to work since its such a short drive and the weather has been so nice lately, in that case MPG=infinite :)

I agree - with the combination of this site and the other I will maintain the up keep of the vehicle to keep it running good for a long time.

Thanks, Z

IN regards to keeping the torque converter locked up and engaging the TCC, wouldn't this mod due just that as he describes it. Obviously he is doing it for another reason, but wouldn't this help FE?

Seemed like a good idea and strike me, thought I would share.

--Z

Nice!
 

That mod would be great! Is this a post from Saturnfans.com? It would be a great day if I can finally tell the automatic what I want it to do...

RH77

Yes, its a post from Saturnfans. I thought it would be great to especially in terms of engaging the TCC and keeping the converter locked. Although shifting would be great too.

He did say in a later post that it took him a few dollars and about 30mins of time to hook up a switch that would engage the TCC and lock the converter since it is done electronically.

If anybody is interested I will keep you all updated. I thought it was great!

Sounds good to me :thumbup: