Hi all I am new to the forum. I have 1999 Ford Zx2 that I have been trying to get as good gas mileage as I can however it has taken a dump lately. I was averaging 38 mpg last summer but then suddenly winter came and I got my worst tank ever at 26mpg. My best tank was 42.8mpg.
It has a 2.0l DOHC Engine with variable cam timing on the exhaust cam. 5 speed manual. Comfort package with cruise control, 14 inch 185 wheels/tires. I recently put Yokohamas on which may be hurting my gas mileage and now I regret not going with the Kumhos that looked like they would had lower rolling resistance and would be quieter. I was a sucker for name branding and tire people's advice. I used to have Firestone Affinity H4s (discontinued?) which were great and quiet but one got a nail and firestone refused to honor the warranty so despite making a good product their service sucked.
I have some modifications most of which I originally put in to improve my performance but some also seemed to improve my fuel economy.
Superchip installed in 2000 to run on 90+octane gas.
K&N Cleanable airfilter
Modified Airbox and intake tube ("Kemanized" they call it)
AFX Underdrive Pulley for the Accessories (mounted on crankshaft) 30% underdrive
gapped double platinum spark plugs to the maximum spec
Magnecore low RMI EMI interference .85 wires (not sure if these matter)
Royal Purple 5w-30 full synthetic oil
Royal Purple transmission oil. (this made shifting so much smoother)
I am in Michigan and with the salt they dump on the roads and constant thawing and freezing make the roads SUCK with HUGE potholes so my tires are only filled to 2psi over spec. 34psi in the front and 37psi in the back. The car is starting to develop rattles which I was hoping would never happen but its inevitable with these roads.
Reasons why I might be getting bad gas mileage: I was in an accident last fall, car looks like it was fixed very well, (just the front bumper was mashed) but then I took it back to get some dings fixed now the door flutters despite repeated returns to the shop to get them to remedy it, (door didn't flutter after the accident). After the car was repaired after the accident I swapped both tie rod ends out myself. I eyeballed the toein pretty good but took it to an alignment shop anyway. Despite them insisting the alignment is perfect the car started wandering to the left. I took it back and they gave me some static. I explained really politely that all I want is the car to go down the road straight. Still more static. So I suggested for them just to change to toe in slightly to the right. They did it. They also said front wheel drive cars require a bit of pigeon toeing. Is this true for newer cars? I have a feeling this is causing my problem. My car is still wandering to the left and its driving me nuts. Its still under warranty but these guys are kind of shady and I dont want them to damage my car.
Finally I got an o2 sensor check engine light warning for the second o2 sensor after the cat. I read on teamzx2.com that this doesnt affect the engine and is just for emissions so wouldnt affect gas mileage. It throws a code every now and then only in the winter.
I just joined too. I believe we have almost the same vehicle. check my garage (i'm not 100% on all of those measurement stats) but yeah, i got a 99 zx2 sport, but with no real modding work done yet.
edit: actually, now that i go back to the beginning of your post again, i realize a few differences between our vehicles. Since mine is the sport model, it has a spoiler and 15" alloy wheels. fog lamps, different seats and a couple other things i don't consider relevant too.
You are certainly getting better gas mileage than me as well. I'm getting 35 max and 25 min, thats measured at fill up, so thats between highway and city.
Anyway, glad someone is a newbie when I am. Hope we Zx2 drivers can learn and together.
They also said front wheel drive cars require a bit of pigeon toeing. Is this true for newer cars? I have a feeling this is causing my problem. My car is still wandering to the left and its driving me nuts. Its still under warranty but these guys are kind of shady and I dont want them to damage my car.
Front wheel drive makes the front wheels tend to want to toe out under power, so slight toe in is usually recommended to counteract this.
If I were you I'd get a 4 wheel alignment done, could be something in the back end making it wander. Also have brakes checked for dragging and wheel bearings checked.
I don't know how it it in the ZX2, but in my '95 Escort, I took a couple of weeks to get used to the wheel not being quite centered ahead of the drivers seat, you might just double check it's not your perception being skewed by this that makes it feel like it's pulling left.
O2 light might just be due to lots of short trips in the cold, a good run on the highway every couple of weeks might clean the cat and other components up a bit and stop that.
I remember The RoadWarrior..To understand who he was, you have to go back to another time..the world was powered by the black fuel & the desert sprouted great cities..Gone now, swept away..two mighty warrior tribes went to war & touched off a blaze which engulfed them all. Without fuel, they were nothing..thundering machines sputtered & stopped..Only those mobile enough to scavenge, brutal enough to pillage would survive. The gangs took over the highways, ready to wage war for a tank of juice
Dave: I have had the under drive pulley on for most of the life of the car and can you believe I am still on the original battery, going on 9 years old? It loses a little charge in the winter though and the green bubble is now red so it may go soon but obviously was not hurt by the alternator spinning slower. The engine may vibrate a little more but the only way for me to know its the pulley is by putting the old one back on.
WestonR: Yep. I should have added above it has cruise control and no spoiler. I also have the 22mm sway bar from an old escort GT but the rear wheel has been making a grinding sound lately under hard cornering which cancels out my ability ro corner hard. (hard cornering allows you to keep your speed a little more constant and enable longer coasting) When it warms up I'll grease the sway bar again and see if that is the problem. I also have aftermarket fog lights that I put on. Unfortunately, after the accident they had to be removed. When I reinstalled them I didn't get them aligned perfectly and it was too cold to spend the hours I need to climb under the car and keep making fine adjustments then checking their aim. They do their job of preventing other drivers from cutting me off most of the time for some psychological reason. Maybe it looks like a bigger car with the fogs on.
RoadWarrior Thanks! I was hoping I wasn't going to have to replace the darn O2 sensor. That's exactly what I have been doing, taking short trips in the cold which may also be contributing to my poor gas mileage. The thing is it is worse than last winter where I was doing the same. Nice Escort Wagon btw!
Anyway here's a followup. I have improved my gas mileage! Last tank was 31mpg. (still not what I want but better) The wander to the left improved after I took it to a Firestone and got a free alignment Check. So it may have been partly perception, partly the new tires needing breaking in. The guy showed me the computer and it turned out my alignment was pretty good and well within spec. There was a slight difference camber and toe in the front wheels and caster was spot on. The rear wheels were fine too. So unless it is the combination of the difference in toe and camber causing the slight wander there is not much that can be done. Next time I get an alignment I'll ask them to change the camber to as perfect as they can. Anyway, I did learn from the alignment check that my right rear brake is dragging a bit. A soon as it warms up I am going to replace the drums and pads. I did the fronts last year. This may be contributing to my poor mpgs.
Anyway, I followed the advice posted here and blocked my grill (minus the fogs) and blocked half my radiator. I blocked nearly the entire radiator at first but that caused my fan to run so took some of the cardboard off. It takes less time for my engine to heat up now to 190 - 2.5 miles driving instead of 6 or 7. The cabin is also warmer. This may have contributed to my better gas mileage which is why I am still not totally pleased. When the weather warms up I'll unblock the radiator but I have to figure out a permanent grill block.
Ok I just took a short freeway trip today and I scanned the ECU with the Scangauge and it still said "not ready". On the way home the my gas mileage suddenly shot up from 33 to 50 and so I scanned it again and then it said "ready". I averaged 36mpg today. So my O2 sensor has got to be part of the problem EVEN with it being after the cat. The freeway trip seemed to remedy it for the time being.