Ford Focus Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
19 Posts
Discussion Starter · #1 ·
Hey everyone, I have a 2002 SE sedan with the 2.0 Zetec. It has roughly 80,000 miles on it and a decent list of mods. I have a full cold air intake with a K&N filter, NGK Iridium Plugs, APC 9.3 mm wires, OBX race headers, OBX Hi-Flow cat with modded 02 sensor, and full Cat-Back Exhaust. I just changed the Oil (castrol gtx high mileage 5w20) and oil filter. I cleaned my K&N, cleaned the MAF, cleaned the throttle body, ran injector cleaner, changed my PCV, changed my fuel filter, changed vaccuum hose, rotated my tires, changed driving habits, etc...

With 50/50 mix of city and highway driving I only get about 17 MPG! For the life of me I cannot figure out why. I only get between 170-190 miles on my tank before the empty light comes on. If i drive only on the highway I still only get around 195 miles to a tank before the light comes on and if i drive only city and can get down to 150 miles before the empty light comes on....

I've been driving it like a grandma lately, and I still see no improvement in MPG. Ive tryed every single gas stations gas in town, and its all the same. I have nothing in my trunk or in the car to weigh it down, and I usually drive by myself with the ac at the lowest setting.

Shouldn't I be at least getting near 22mpg or more? I mean my 1995 chrysler lhs 3.5L with 160,000 miles gets 18mpg.... and my 1999 P.O.S. Ford Windstar 3.8L With 110,000 miles gets 18 as well...
 

·
Registered
Joined
·
6,092 Posts
Top O2 sensor going off will make you run rich, and lower gas mileage. See if there are any impending codes, or just change it.
 

·
Registered
Joined
·
10 Posts
Excuse me for asking, but what is an "impending code"? I mean, codes are either generated or they are not. Yes? There is no gray area. How can a code be impending? A trip to the dealer's Psychic Futureteller Ford bay will tell a person this?;)

Eurodavid

PS Agree on the O2 sensor. My '03 Zetec ZTW did similar, and after doing every other thing, I decided to change out that O2 sensor, and woudn't ya now it, that was it. Gas mileage slowly creeped back up to 23-25 mpg.
 

·
Registered
Joined
·
6,092 Posts
Excuse me for asking, but what is an "impending code"? I mean, codes are either generated or they are not. Yes? There is no gray area. How can a code be impending? A trip to the dealer's Psychic Futureteller Ford bay will tell a person this?;)
You have to look for a dealer with a Vardo parked out front... :D

Yes, there is "gray area". In most cases the ECM doesn't pop up a CEL as soon as some sensor sends a signal that is out of range. It stores the mistake and waits for a specified amount of run-time to pass with the same signal being out, then it displays a CEL. You can read the impending codes that are stored in the ECM before it shows a CEL.
 

·
Registered
Joined
·
1,027 Posts
17mpg that sucks..my car has a big leak in teh egr and it not that bad..fix the o2 sensor for sure
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #7 ·
I went to autozone for the free ODB code scan... my car didnt throw any codes at all. No 02 codes or anything, does this still mean the 02 is bad?

also i forgot to mention i get a funny idle sometimes, every so often the RPM's will go up and down very slightly. I dont know if that has anything to do with it.
 

·
Registered
Joined
·
6,092 Posts
I bet the idle gets funny when the car is warm. If so, that could be due to air/fuel mix fluctuations caused by a bad O2, or a fuel feed problem... dirty injectors, high rail pressure, bad tune. Won't hurt to change the O2, but if the problem doesn't go away with that, then check into fuel feed.

BTW, how did you mod your bottom O2?
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #9 ·
actually it idles funny when it first starts up, not just cold starts though, warm ones too. after its been running for a 10 minutes or so, it seems to not do it as much, but on occasion i'll get a small rev. ive been to autozone and advance auto parts today and had both of them check the ODB, and no codes at either place, so i have a feeling that my top 02 sensor might be fine...


i modded the bottom 02 sensor like this...
http://www.focusfanatics.com/forum/showthread.php?t=130381
its a guide from FF on how to turn your CEL off and not get catalyst errors after installing a hi-flow aftermarket cat. its just soldering on a little resistor and a capacitor on the sensor to trick the computer telling it you sill have a stock cat.
 

·
Registered
Joined
·
971 Posts
Tire pressure? Just kidding; you rotated tires so clearly you filled 'em up with proper psi, duh.

Instead of the little wire thingamajingy on the rear 02 sensor, why not get a MIL elminator? I bought two from ebay when I had a gutted catalytic converter, screwed the little adapter in, and threw no codes.

Also, maybe check plug gap? I know, I know, too simplistic, but what the hey...can't hurt, can it?

If it's an automatic, maybe change the tranny fluid? Again, simplistic. Heck, if it's a manual, change the tranny fluid. Of course, why THAT would cause poor mileage is beyond me, so feel free to entirely disregard.

--Scott
 

·
Registered
Joined
·
6,092 Posts
When did you first notice the drop in mileage? Was it shortly after any mods? How long have you had the header on?

Or it could be a couple of simple tune issues together... :dunno:
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #12 ·
well i did the wire job on my bottom o2 sensor as it only cost me 2 bucks for the little 99 cent capacitor and the 99 cent resistor.
MIL eliminator? do you mean something like this...

http://cgi.ebay.com/2-pcs-Oxygen-O2...a00e654e8&_trksid=p3286.c0.m14#ht_3170wt_1114

if thats what your referencing too then what i did was basically the 2 dollar version of that.


i noticed a drop from 19 mpg to 17 mpg after all the mods... but when i got the car stock the most i usually got was around 19-21 mpg and that was main reasoning for my first mod of the CAI... then after that i just got hooked on modding and noticed that things that you think would increase mpg have just put it on a slow decline...
ive had the headers for about 4 months now, and just got the catback about 2 weeks ago. if anything i thought that the complete high-flow exhaust from the engine all the way to the tail pipe would help my mpg a little...

and the sad thing is, while my car sounds and looks cool, its still as slow as when i got it stock...or if anything it feels like it has a little more drag then when it was stock. could a programmer fix that?
 

·
Registered
Joined
·
5,036 Posts
A proper tune will help thw aftermarket parts work better together. Contact Randy at FocusSport and he'll set you up with a good tune.
 

·
Registered
Joined
·
6,092 Posts
Yep, get an xcal3 (or 2) from FS and a high octane tune, that will wake up your mods.

For best gas mileage, make sure you have a good wheel alignment (zero front toe, and minimum, ~15 deg, toe in on the rear), improve your grounds, make sure all your engine/accessory pulleys and wheel bearings turn smoothly, get a UDP, keep 34lbs cold (or a bit more) air in your tires, makle sure the plugs are gapped right, use synthetic oil, and don't floor it all the time, lol.

If I were you I'd change the top O2 anyway.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #15 ·
i changed it out... same stuff. i drove a good 40 miles today... used up a good quarter tank of gas. ive still got that quirky idle.... i bought a new throttle position sensor at orielys today, ill put that on tomorrow and let you know if that makes a difference... tires pressure is good, and i just got an alignment last month.

...as far as tuning goes, i've been considering an xCal, but im not familiar at all with programmers. if i plug it up and do it myself, will it be able to tune up to my mods and give me some good results? or do i need to go to a performance shop and get a custom tune for it to work properly... i know a custom tune would take the most advantage out of it, but if i can do it myself with just that and it give me pretty good results, then ill be happy with that until i come across some more $$$
 

·
Registered
Joined
·
6,092 Posts
Sorry to hear it made no difference. What do your plugs look like?

The best thing about getting an Xcal from FS is that Randy writes the tunes and he knows Foci. :bow: That made a big difference in the performance of my car, as I slowly mod it to where I want it, then I'll get a more specific dyno cam/ECM tune. My mileage improved after the tune, as long as I drove the same.

You can change many of the parameters in the tune with the xcal (not recommended, unless you know what you're doing and have good reason for it), but it comes with at least one tune already on there (there's room for 3 on an xcal2). You can also data log (optional programing) and read/remove codes with it.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #17 ·
plugs are good, just popped em all out and there still in great condition. ngk iridiums...

so ive been back and fourth to napa auto parts, oriellys, and auto zone, only to have each one of them give me 2 different tps sensors, and all were different, none close to fitting. real disappointment. the third one napa pulled up looked like it may work, but they dont even stock it in the state.... and the dealership wants close to 90 bucks for it...i said no way to that. looks like im dead in the water on this one....

so im still stuck with a jumpy idle, terrible gas mileage, and terrible bogged down acceleration....
 

·
Registered
Joined
·
6,092 Posts
Call Tousley Ford (sponsor here), they sell parts to FJers at 10% over cost, and get them out real quick. You will get the right sensor from them. Ask for Mike and tell them you are on FJ, or post to Steve in the sponsor section for answers to part questions.
 

·
Registered
Joined
·
239 Posts
Is it idling real bad? Did you check your vacuum lines? If you don't know how to check them, get a can of carb cleaner and start spraying the lines and ends. If it revs up and runs better you have found a leak.

Also it wouldn't be a bad idea to check the fuel pressure. But since the focus doesn't have a shrader valve on the fuel rail you have to have a computer to read it. Correct me if im wrong but i don't think a regular obd2 scanner will work.
 

·
Registered
Joined
·
19 Posts
Discussion Starter · #20 ·
its not idling really bad.. just very slight ups and downs, it'll go from about 800ish RPMs to 1000 RPMs to 1100ish RPMs then back down then back up again... things like that.
 
1 - 20 of 22 Posts
Top