nathan2003

hey, On my 1991, 305, Fuel Injected, camaro i was getting poopy gas mileage.. I've seen people post asking what peoples averages are and mine is no where close to those... right now over this last summer i've been averaging 7-12 MPG... Now this is with a 91, 305, no-emissions, flowmaster exhuast, 130,000 miles, 4 spd Auto tranny,, has OD.. stock rear end whatever it is ... ... i mean theres nothing drastic about this car that i can see that should make it perform this poor.... now heres the scary part... when i figure my MPG I am driving as nice as I can,, I'm trying to get the best mileage i can ... don't even take the car over 2500 or 3000 rpm.. no rompin or anything... and all my driving is done both in town and on highway and half and half... and well just so you know my town isn't like a city its a population of 7000... so there arn't any traffic jams or stupid stuff like that.........


so i did a tune up to my car new plugs , wires... cleaned injectors... and still a poopy 9 MPG... i'm also runnin 91 octane... I am just curious as to what could be going on to do this ... did my motor just go to **** on me or what .... oh ya heres the kicker ... last summer about this time my car was getting 22-27 MPG... something hasta be wrong for a drastic thing like that...

but as some of you know i took all that **** out put in new hei, intake, and carb.... i havn't had a chance to test it out yet and check my MPG with this setup cause my cars gettin a new steering column right now but arn't carbs suppose to get wrost MPG then TBI.... well if anyone has had this problem with there TBI or any setup and knows a cure let me know ... thx...


later
vetter

The Happy Viper

Replace the fuel filter...

Fredless

what he said and stop wasting your money on 91 gas...89 gas is fine unless you have advanced timing.

Bwells92RS

Check your fuel tank and the feul tank filler neck joint. I have a major leak there that made my gas evaporate very fast.

FreeLoader

In my personal expirience...going from mid to super added quite a bit of mileage to my car per tank.

personally I wonder if between the overdrive and the 2.73 rearend(assuming you have one, I do) if its actually too low for its own good....as in its great for highway...but horrid for city, because it works out to be just too low...

Stop me if what I'm saying is completely retarded.

FreeLoader

Could you tell me how a leak in your filler pipe could cause a gas mileage problem...other then the fact that it works off of pressure and all...

nathan2003

i'm pretty sure that my tank is not leaking.. i've done a visual inspection and everytime i open the cap there is a quite a bit of pressure built up still so i'm very positive that i have no leaks at the time.. not sure what else there is to do about this ....



vetter

Bwells92RS

I park my car in a garage. Ever time i closed the garage door i could smell gas. I looked everywhere (so I thought) for a leak. Couldnt find one. But I noticed the filler neck was loose. I could move it about a 1/2 inch either way. I still had presure under the cap but I was loosing alot of vapor where the filler meets the tank. I had it repaired and I get close to 290 miles on a tank with lots of trafic in SOCAL.

steve8586iroc

You didn't mention how it runs as far as drivability. Also did you check or replace the o2 sensor?

Steve

nathan2003

it drives good.... about as good as you can expect out of a almost all stock 305.... there arn't any signs of problems with how it runs, seems to be doing good there.... just replaced the 02 sensor not long ago thinking that was the prob and that wasn't it,, thought maybe catylac converter was clogged but when i replaced my exhuast i checked that and that is still good to go... i've had the car sit for like 3 weeks straight and the tank didn't loose a bit of gas... no gas smell or signs of fuel loss ... i mean in 3 weeks time a noticeable amount of gas would escape .... soo... ??




-Vetter

nathan2003

first tank of gas ran through with my carburetor setup and mileage was 11.5 MPG. This is about what my car was getting before. Does that sound reasonable for a carburetor or what ? i'm surprised it was the same as fuel injectedc... i just wish it coluld go 20 or even 16 mpg...



nathan vetter

brodyscamaro

Click the link in my sig. Check my specs. I can get 15 city and 20 highway.

nathan2003

wow.. big progress made today, i had 15 MPG ! ! wow, but like all of that was highway to not to much room to brag i suppose. i have turned the fuel pressure like way way down and the idle mixture screws down and the carb is still running very rich, it puffs out black smoke and has lots of carbon build up happening. so, i live in western iowa and my 305 is stock but no emissions , flowmaster exhuast and this new intake and carb, thats all it has for modifications, what should i change my rods and all that little stuff too ?? i looked in my book and am not sure how far i wanna go... if i remember right i was thinkin stage 7 or whatever you wanna call it but, if anyone could just give me a brief definition on how to install new rods and springs and what ones i need-- to bring my richness down, because words of wisdom from all of you are usually a bit easier to understand then words from a manual thx alot, keep ya informed of progress..




nathan vetter

MechCD

Some of that emissions stuff actually helps your mileage and doesn't reduce HP by too much. I can't think of which ones atm

FreeLoader

I just changed my fuel filter and its givin me a considerable increase in gas mileage...at least 2-3 mpg.

Its still nothin to brag about, but damn...for such a cheap change...maybe you should just do it for fun.