WTF poor gas mileage

T

TeamPlayers

Member
:
P5 and some other econo box
Ok so I was on vacation for 30days and the whole time the P5 stayed in the garage. But every since I've been back it seems like I'm getting really bad fuel economy. I've filled it up, reset the OD and right now I'm just under half tank and only 130mi. driving really slow.

Any suggestions?
 
You were gone for so long and missed the car so much, that you are probly driving it harder than normal :)

but,
It could be the huge change in temperature/climate since you have been gone and the CPU fuel air ratio has not yet adjusted to the different climate conditions. Since our car runs pretty rich, this may be an explanation. Give it another week or re-set the CPU and see what happens.
 
just posted this on another page...


I noticed something funny tonight that I must share with all of you. my tires "felt" under-inflated recently so I drove to a gas station and went straight to the air hose. The air hose has a built-in pressure gauge that pops-up when you press it to your tire's valve as you all already know. The pressure on the gauge read 30 PSI. Just a tad low. I then pulled-out my Accurite digital pressure gauge and WOW...it read only 22.5 PSI. I wasn't sure which was correct, but I was banking on the accurite. I inflated my tires to 33PSI on the Accurite. The gauge on the air hose read over 40PSI. I don't know how that can be, but I checked it with a third (non-digital) pressure gauge that I own and it confirmed my Accurite's readings. Basically, it can very well be that people are inflating their tires using the hose's pressure gauge and are therefor under-inflating their tires which is contributing to poor gas mileage in the winter time. I realize that dividing by 14.5 gallons is incorrect (as you've pointed-out), but it won't increase my MPG by much. In any case, the tire pressure seems to be my main culprit and after filling-up tonight, I am anxious to see what my result will be. I always fill-up until the pump stops and then re-set my Trip counter. Then see how many km until my gas light goes on.... I'm sure there's something else wrong somewhere... Will re-setting my ECU actually do anything like some of you have posted? Thank you all. Go out and buy a digital pressure gauge...WORTH EVERY CENT!!
 
Weborific said:
just posted this on another page...


I noticed something funny tonight that I must share with all of you. my tires "felt" under-inflated recently so I drove to a gas station and went straight to the air hose. The air hose has a built-in pressure gauge that pops-up when you press it to your tire's valve as you all already know. The pressure on the gauge read 30 PSI. Just a tad low. I then pulled-out my Accurite digital pressure gauge and WOW...it read only 22.5 PSI. I wasn't sure which was correct, but I was banking on the accurite. I inflated my tires to 33PSI on the Accurite. The gauge on the air hose read over 40PSI. I don't know how that can be, but I checked it with a third (non-digital) pressure gauge that I own and it confirmed my Accurite's readings. Basically, it can very well be that people are inflating their tires using the hose's pressure gauge and are therefor under-inflating their tires which is contributing to poor gas mileage in the winter time. I realize that dividing by 14.5 gallons is incorrect (as you've pointed-out), but it won't increase my MPG by much. In any case, the tire pressure seems to be my main culprit and after filling-up tonight, I am anxious to see what my result will be. I always fill-up until the pump stops and then re-set my Trip counter. Then see how many km until my gas light goes on.... I'm sure there's something else wrong somewhere... Will re-setting my ECU actually do anything like some of you have posted? Thank you all. Go out and buy a digital pressure gauge...WORTH EVERY CENT!!
Click to expand...

its the government man! there out to get you with gas prices.

the car eats up gas + its winter. i dont even get 230 MPG checked replaced just about everything, i gave up the car runs in tip top condition pulls great for a N/A car but the gas milage sucks. although my story is a little more different, which i've already explained in previous posts, im sure if i did expressway driving everyday etc, which i dont i could easily do 300 but im a suburban guy work in the suburbs play in the suburbs car uses alot of gas to start, run in stop and go traffic gunning there driving slow here. you know suburban driving.

dont worry man summer is approching u'll see better milage
 
Matthew1785 said:
i dont even get 230 MPG checked replaced just about everything, i gave up the car runs in tip top condition pulls great for a N/A car but the gas milage sucks.
Click to expand...
Talk about setting lofty goals lol
(peep)
 
I know it aint the ECU cause when I came home the battery was dead. The tire pressures "appear" to look fine but I'll throw a gauge on them and see what happens
 
I'm at work, gotta make this quick.... occured to me, tire SIZE would alter mileage, wouldn't it?? P5 has very uncommon tire size, so we all buy a close match, but speedometer is usually off by a few percent. In my case (if i remember correctly) when my speedometer reads 104 km/hr, my ACTUAL speed is 100. so based on stock tires, my car THINKS i'm travelling a certain speed/distance when that's not the case. In my case, i beleive that i'm therefore getting even LESS mpg that i thought... Anybody can agree/disagree with this?? any theories... boss here, gotta go.....
 
Weborific, it's true that changing tire size would alter your speedo and odo. Most people, however, usually go with a 205/50/16 or something close to that, which barely affects it. I believe it's off by less than one percent. That wouldn't account for people getting 20ish miles/gallon when the car is supposed to be getting 30 mpg.

Going w/ 18's or something, however, would drastically alter your speedo.
 
well, for me, the last few tansk have been strictly city driving (maybe 5% highway)..and with the cold, and the winter gas and winter tires, i am getting a dismal 20mpg.....but if I had 50% highway, that obviously would change (well, at least it better:p)

but that is gas mileage in the worst scenario (cold, winter gas, tires)...so I am sure in the summer that would change (I have only had the car since octoboer, and my mileage was better then (warmer and stock tires)
 
jonlong said:
what's the difference between winter gas and summer gas?
Click to expand...

Winter gas has more additives, but I'll let someone with better knowledge handle that question... I'm gonna post my results from my ECU reset SO FAR. I reset it this afternoon and then let it idle for 10 minutes. I drove the car several hours later after work. I wasn't sure what to expect, but here it is so far:
(car is AUTOMATIC, currently calculated at dismal 16MPG)

- the car was much more responsive, even at -15 degrees celcius! Just lightly touching the gas pedal made my RPM gauge jump. I didn't have to press as hard on gas pedal to get car to move.

- car now moves a touch faster when releasing the brake pedal from dead stop. It used to crawl very slowly. It's now faster, even when crunching through thick snow!

- car doesn't seem to slow-down as fast while driving and releasing the gas pedal

- it seems my car is much quieter. I'll know tomorrow for sure, but as it was before the ECU reset, I would hear my car idle from inside my house with the doors closed when starting with my remote starter. It would sound like deep bass. right now (maybe cause car hasn't cooled long enough (only 2 hours)) I can barely hear my car while I'm standing right beside it.

- My RPM gauge needle used to be pretty damn stable at idle, but after ECU reset, it bounces slightly up and down (like +/- 1 mm). From what I've read, this should go away. Seems alright though. idles at around 800RPM.

That's it so far. I'll post my gas mileage next week. So far, the ECU reset looks very promising in my case. After all the maintenance I've done, how much lower than 16 mpg can I possibly get??!! OK, later!
 
My milage went down the gutter as well after I finished my transmission swap.
Though there's TOO many factors that come in hand for my build.

I went from stock (engine wise) at 32mpg...
To 23mpg after lsd, flywheel, intake + exhaust + wheels(smaller and lighter though)
(Not every part installed, but things that may affect the mpg)

Note : the car was down from september --> end of january
 
I'll do an ECU reset when it gets warmer out and I'm not running my winter tires and see what that does.
 
Please log in or register to reply here.

Similar threads

BenjiHoggi
Protege5 won't idle after refueling (EVAP/O2 sensor issue?)
Replies
10
Views
2K
BenjiHoggi
BenjiHoggi
Halfbaked
    • Like
2003 Protege5 Bogging
2 3
Replies
44
Views
8K
pcb
P
S
P0117 and P0304 Codes (Protege5)
Replies
5
Views
610
Saudade
S

Latest posts

Back