Exhaust leak = bad gas mileage?

[itreflop117]

I have the 4AFE 1.6L engine. 3 spd automatic. according to all the websites this car gets the worse gas mileage out of all the corollas. that's fine.

the thing is when i get a full tank i drive 40 on regular streets sometimes even slower not gunning anything. and i take the high way back to home after school going 70.

It's about 15 miles roughly there and 15 miles back at max. My concern is whenever I get a full tank I can barely make it to 200 miles. I think it would be a lot more fair if it would be around 250 miles for a full tank. but I don't know. The only thing I can think of that is causing this is my exhaust leak right before the muffler. (not the tip but before the giant coffee can thing where it bolts up).

So my question is this, what do you think could be causing my poor gas mileage? and does the size of the exhaust leak have anything to do with that? (the bigger the leak, the worse my gas mileage gets?)

Thanks for you guy's time, I appreciate all the help I can get.

[jawsofire]

I have the same engine and everything. Live in the same area, also have leaks on both sides of the cat. I get about 220 on a full tank and i drive it rough. At least 50 on streets and about 80 on highway. I don't think the leak is the problem. You might just need a tune-up.

[speedy25]

I get 300-350 on a tank in my wagon.

There are a LOT of things that would make your mileage poor. You just need to attack them a little at a time. Start with a leakdown test of the engine to make sure it is in good enough condition to make a difference in mileage.

-SP

[itreflop117]

Originally Posted by jawsofire

I have the same engine and everything. Live in the same area, also have leaks on both sides of the cat. I get about 220 on a full tank and i drive it rough. At least 50 on streets and about 80 on highway. I don't think the leak is the problem. You might just need a tune-up.

I just recently got a tune up before winter. new plugs and wires. got the whole shot and oil changed. I don't know what else it could possibly be. damm..

[itreflop117]

Originally Posted by speedy25

I get 300-350 on a tank in my wagon.

There are a LOT of things that would make your mileage poor. You just need to attack them a little at a time. Start with a leakdown test of the engine to make sure it is in good enough condition to make a difference in mileage.

-SP

sorry i'm a newbie at this. what do you exactly need to do in order to leak down an engine? sorry, thanks

[speedy25]

cheap leakdown testers are available at Harbor Freight but you have to change the gauges because they are crap. You also need an air source. Basically you put air in the cylinder at TDC and see how much leaks out. Great for finding out how bad your rings and valves are.

I do this test on EVERYTHING I work on just so I wont be wasting my time if the engine is worn out or has bent/leaky valves.

-SP

[trife96]

Originally Posted by speedy25

I get 300-350 on a tank in my wagon.

There are a LOT of things that would make your mileage poor. You just need to attack them a little at a time. Start with a leakdown test of the engine to make sure it is in good enough condition to make a difference in mileage.

-SP

Yes, ALOT of things can cause bad fuel mileage...Why not start with checking tire pressure first? That would be easiest

[Bitter]

also don't drive 70mph with the 3spd, do the speed limit. If 70 is the speed limit then get in the slow lane and do 55.

[Monkey123]

What year is your car? I have a 1993 Corolla with an exhaust leak near the flex pipe and I'm getting 27 to 30 mpg on a 3 speed transmission with no overdrive. The engine has 266700 miles on it. Since you did a recent tune up, the gas leak will be on your fuel lines.
There are 3 or 4 lines if I remember right. You have the main fuel line, the return line, the evap line, and the overfill line. If the car is old, likely there will be a small leak. Mine leaks at the overfill line and the return line. I changed all of them and I ordered from Schaumberg Toyota in Chicago land. One more thing, don't forget the gasoline tank. If the gas tank leaks, likely will be at the seam. Why don't you fill the gas tank to 5 gallons and drive to see if you get more milelage. This would test your gas tank or fill the tank full and drive a bit and jack the car up and check for dampness or wet spot around the tank. Also the the smell test. Good luck!

[itreflop117]

holy jesus. thanks for all the replies. i appreciate all the help. I think i'm just gonna get fed up with this car and all the problems it has had and buy a newer WRX... lol but thanks for the help i really do appreciate it.

well this is what i'm going to do. according to websites like i previously stated the 3spd auto should be getting 23 city and 27 highway. so mixed i'm guessing 24, 25...

what i just did was that i filled my tank to 9.6 gallons... so technically i should be getting around 230 miles with 9.6 gallons.

if it doesn't come out to be about 230 miles. then i know somethin is wrong..

but yea thanks for the help and advice, i'll keep you all updated. thanks once againnn