my mpg is awful. i cannot figure it out. recently did a head gasket and before was getting average of 22mpg. now after i am getting 16. i don't know what has changed. i tried changing o2 yesterday with no change in mileage. vacumm lines are 2 years old. fuel filter is 1 yr old. di cassette works. plugs are fine. i can smell the fuel in the exhaust for some reason it is running very rich. any ideas? a bad pulley wouldn't effect it would it? i need to replace what i think is the idler pulley.
noxben
bad fuel mileage
karrodjeller - resize your signature please
As for BAD mpg - my moms 97 ng900 SE Turbo is the same crap - except it's never had "good" mileage around town.
Try unhooking your battery again - short the two leads together and just let it sit for 5 minutes to be sure. This will clear EVERYTHING your ECU has learned and reset it all. Reconnect it and drive the car as you normally would for about 20 miles (or over a few days). The car should relearn and adapt its self back to the proper fuel maps and trims long and short term. GM's are very good about this.
My mom’s car gets about 26 mpg highways when I drive it and about 24 when my mom drives - yet I am the one in sport mode and kicking the cars ass. Around town it's been getting about 17-19mpg which to me is bullshit. The car is in good mechanical shape and has no reason to be so poor in fuel economy. I've never come across another car with the like problem. You are the first I've heard about now man - so perhaps we can figure this out. I too have replaced the front 02 sensor (OEM) good vacuum lines new plugs and a good DI. The fuel filter I've neglected to replace as of yet - but it's got good fuel pressure/volume right now. The exhaust doesn't reek of gas on ours however.
The os1 and os2 are oscillating just as a new car would - and the trims are where they should be. Now when I hooked onto a Snap On Brick scanner is told me the car was a Cali. Emissions car - this was odd to me and I can't explain how it would affect the MPG by being a "Cali" car. I've yet to clean the IAC - so perhaps this could be a cause, or contributor. More details on your car I guess would be needed. See if we can figure out the dilemmas.
As for BAD mpg - my moms 97 ng900 SE Turbo is the same crap - except it's never had "good" mileage around town.
Try unhooking your battery again - short the two leads together and just let it sit for 5 minutes to be sure. This will clear EVERYTHING your ECU has learned and reset it all. Reconnect it and drive the car as you normally would for about 20 miles (or over a few days). The car should relearn and adapt its self back to the proper fuel maps and trims long and short term. GM's are very good about this.
My mom’s car gets about 26 mpg highways when I drive it and about 24 when my mom drives - yet I am the one in sport mode and kicking the cars ass. Around town it's been getting about 17-19mpg which to me is bullshit. The car is in good mechanical shape and has no reason to be so poor in fuel economy. I've never come across another car with the like problem. You are the first I've heard about now man - so perhaps we can figure this out. I too have replaced the front 02 sensor (OEM) good vacuum lines new plugs and a good DI. The fuel filter I've neglected to replace as of yet - but it's got good fuel pressure/volume right now. The exhaust doesn't reek of gas on ours however.
The os1 and os2 are oscillating just as a new car would - and the trims are where they should be. Now when I hooked onto a Snap On Brick scanner is told me the car was a Cali. Emissions car - this was odd to me and I can't explain how it would affect the MPG by being a "Cali" car. I've yet to clean the IAC - so perhaps this could be a cause, or contributor. More details on your car I guess would be needed. See if we can figure out the dilemmas.
I unplugged the ground cable when i got home from work. i will either plug it in tonight when i go to play soccer or tomorrow when i go to work and see what happens. i have my doubts. it seems like i have tried replacing the o2 (only have one) and still had a cel. makes me wonder if there may be a short in the harness somewhere, or maybe a map problem? another option became apparent to me. maybe fpr, injector or fuel check valve? since it is running really rich.
My gas mileage isn't great either... I am pretty much guessing that a lot of this has to do with the fact that I am on winter rubber (very very soft), have bigger rims, and it's extremely cold outside. I'm hoping it will be better once spring comes around... I'm getting 23 average right now and in the city I get 18-19... everything's in perfect mechanical shape.
edit - my moms is getting 17-20 mpg OVERALL and that's MOSTLY Highway driving at about 65-75mph.
well, reseting the ecu worked for a bout 5 min then my cel came back on. which doesn't make since. it is a 1 day old o2 sensor.
how do you guys get such crappy mileage? i have sqr stage 4 and all the accompanying shit and staying out of the pedal on the highway i can get 32...getting on it alot i can get 28-29.
although i did have horrible mileage at one point...i unplugged the fuse for the 02 heater circuit and i had good mileage again...although this was after a new o2, new fpr, etc etc...
although i did have horrible mileage at one point...i unplugged the fuse for the 02 heater circuit and i had good mileage again...although this was after a new o2, new fpr, etc etc...
These aren't 9000's buddy - these are GM produced engineered by Saab Cars with the trionic 5 in my case. I drive my moms car with the foot of an 80 year old 90lbs woman and I can manage 19mpg around town.... with sport mode OFF. I know the autoshitboxes are supposed to get slightly worse fuel economy then a standard - but NORMAL I thought was about 22/28 for these ng900'ssaabkid37 said:
Recent thought might be that the DI could be on it's way out - but to cause such a drop in fuel economy and NOT performance - I doubt it. Not saying it's not on it's way out however, but it's not the larger contributor to this fault.
I need to re-connect it to a TECH II again and look at the fuel trims - could be something else. Wish I had a spare ECU for this car to test out for a few weeks and see if it could be a glitch in the programing. That's the least likely - but always a possibility.
COuld be a failing cat - never rule out that possibility - a cat which is not efficient can still function enough to keep a CEL off and reduce overall performance slightly, and kill fuel economy. A Scanner/Tech II can show you the os1 and os2 graph/voltages if you have a ng900 which is OBDII (which I thought they did begin in 1994 on the ng900's) but not certain if they did have 2 os units or not. You say you only have one which makes me wonder if they started doing the true OBD2 sonner like they said they had...
You're getting close to 544 miles per tank (64 liter tank=16.9 gallons) on the highway. On average I get 350 miles per tank, or 21 mpg. I used to get about 425 miles per tank, but that was before mods...
my moms STOCK ng900 SET get's about 325 miles to a tank on a GOOD week..... Still not sure how many gallons the tank holds - I think it's about 14-15 gallons like my 87 9K
i actually don't have a cat, but before my gasket my mileage was good. i got 31 on a drive from knox to dc. and better city mileage before as well. there are so many things i need to test i guess. di, fpr, ecu, that is a lot of crap. hmm. whats this about a o2 heater fuse?
I was thinking that my car was obdII as well, but then double guessed myself when reading that obdII didn't come out til '96.
I was thinking that my car was obdII as well, but then double guessed myself when reading that obdII didn't come out til '96.
Ok with upgraded FMIC, 3" DP w/Cat and 3" Air Box Mod I average around 17 around town and on the freeway if I set the cruise and dont touch the pedal it will do 27MPG. Oh and its an Autobox too. You rmileage sounds about right to me from what I have heard from allot of other people with 9-3's.
It might just be a perception thing...
In order to get the advertised mpg around town you have to be VERY VERY VERY light on the accelerator. Like barely touching it light. and accelerating slow enough to piss off all the people behind you at the traffic light.
The problem with city driving is that there are too many variables.
Do this.
1.) Get on the highway when there is no traffic. (womewhere where it is flat, not hilly)
2.) accelerate up to cruising speed
3.) set cruise control to 65mph
4.) take your foot off of the accelerator
5.) clear sid fuel milage
6.) cruise for a few miles without touching your accelerator, brake, or going up or down any hills.
Tell us what your milage is.
When I do this I get about 35mpg, in a much heavier 9-5 Aero.
When I drive fast (like I usually do) not thinking about milage, I average 23.5mpg city and highway.
Around town it's probably 16-20mpg.
Remember, the biggest variable in determining your milage is the driver and how he or she drives. Condition of the engine etc. is a distant second.
When I first got my car i was averaging much higher milage than I do now, cause I got used to the acceleration of the turbo, and used much more subconciously.
In order to get the advertised mpg around town you have to be VERY VERY VERY light on the accelerator. Like barely touching it light. and accelerating slow enough to piss off all the people behind you at the traffic light.
The problem with city driving is that there are too many variables.
Do this.
1.) Get on the highway when there is no traffic. (womewhere where it is flat, not hilly)
2.) accelerate up to cruising speed
3.) set cruise control to 65mph
4.) take your foot off of the accelerator
5.) clear sid fuel milage
6.) cruise for a few miles without touching your accelerator, brake, or going up or down any hills.
Tell us what your milage is.
When I do this I get about 35mpg, in a much heavier 9-5 Aero.
When I drive fast (like I usually do) not thinking about milage, I average 23.5mpg city and highway.
Around town it's probably 16-20mpg.
Remember, the biggest variable in determining your milage is the driver and how he or she drives. Condition of the engine etc. is a distant second.
When I first got my car i was averaging much higher milage than I do now, cause I got used to the acceleration of the turbo, and used much more subconciously.
Speaking of cats, since there's no oxygen sensor behind my catalytic converter, does that mean i can safely straight pipe it? (We do not have emission testing in Michigan, so that is not even an issue.) I wouldn't have any CELs or anything, would I? I also want to remove the resonator in the inside of the exhaust and just rock the outside muffler.
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