gsean400

I fixed the hose that was leaking. I cleared my chek engine and it hasnt come on for a month now. I pretty much put in 10$ everytime i go somewhere. i took my last 10 and drove to my cousins. Now i dont think im going to make it home. Happy thanksgiving

MasterKwan

I'd fill it up and see if the gauge is reading right. If you really are using that much gas, you probably shouldn't drive it because you'll kill the cat's (if you haven't already). I'm thinking I'd suspect a lying gauge.

gsean400

I thought the gauge was a liar too but what has been telling me i have been getting a 7 mpg average was my navi. I also have noticed my gas needle goes down fast!

brainsurge

CEL on? (edit: just read your post again..what were the last faults?) With that gas consumption i would check the gas tank for leaks^^ Maybe oxygen sensor gone bad, but still thats a terrible mpg.

MasterKwan

You're depending on instruments but, not making direct measurements. Fill it with fuel, drive it, see how much fuel you use.

IF it really is using that kind of fuel, it sounds like the evap system might be sucking fuel out of the tank. This can happen if it's plumbed wrong. The intake manifold vacuum is only supposed to be connected to the tank through a switch so, the ecu can control when it sucks out the fumes then close off the vacuum. If you have constant vacuum to the tank. That might explain this.

Considering it started with you messing with the evap system. That's where I'd go.

RamAirRckt

Evap leak kill mpg, no, that isn't the problem. If you are getting 7 mpg, that is a huge amount of fuel being wasted somewhere, leaks (is it leaking fuel on the ground?) .

Gotta be something else making it that rich to burn THAT much fuel if it NOT leaking it. Look for a leaking fuel line (solid fuel, not vapor fuel, a solid fuel leak will NOT trigger a OBD2 fault)

The evap system is really simple. The tank is a closed tank (non vented), so any vapors must be manually vented out or the tank would expand like crazy when it is warm out. So the top of the tank has 3 lines, 1 vent (vapor), 2 solid fuel, one is supply, one is return. The vent goes to a canister with a solenoid valve (closed engine off and engine on throttle closed) with a a charcoal bed in it and it absorbs the vapors, then when the car is running, and when throttle is opened, it will open the canister fully to the allow the engine to suck (negative pressure) the vapors out of the charcoal canister and the tank. Simple really.

Now a evap leak is measured by closing the solenoid and looking for it to hold a negative pressure between the engine and the canister, and if it has the solenoids, it can measure between the tank and the canister. it COULD have a solenoid on the tank side to check the line between the tank and the canister, or it will have to trust that the gas cap is on and suck down the tank and the line between the canister and the tank. All depends on how far they went.

A loose/bad cap will fail evap. And will get worse mpg due to vapor loss of the fuel. But 7 mpg? No. I would not think so.

You should notice a hiss/rush of air when you remove the gas cap. That is air going IN the tank, not out. Make some smoke (no flame!!!!) near the cap when you loosen it, you will see it suck it in the tank.

gsean400

^^^ very helpfull. I learned something today Lol so is my car running rich then? I dont see any leaks on the ground. But when i did do a leak test i found a leak by the gas tank. It wasnt that bad and the one in the front was, so i did the one in thefront cleared my check engine and it hasnt come on since.. But when the check engine came on all this started happening.

brainsurge

If you have an obd reader with live data function, you can just see your oxygen sensors. if one of the front ones is giving faulty data, it could cause the ecu to rich one bank up.This with an Android Smartphone + App Torque (around 4$) can show you all 4 oxygen sensors on one screen.
A leak in front or close to the oxygen sensors might also cause that condition.

islexusred

i was getting a poor MPG also and CEL ( P0430) comes on 2-3 times between fill ups. tried switching o2s to determine if an o2 sensor is bad but the same CEL came back again.. so i decided to look for exhaust leaks .... to my surprise i found a gasket leak right after the left cat before the o2 bank 2! went to autozone got 2 gaskets for about $12 and went to Midas they swapped them out for $50. the old gaskets looked horrible, they were deff leaking and fooling the o2 and make'm think the engine needs more gas. i was getting bout 250 miles per tank ( if am lucky) ... now i drove 230 miles and barely passed half of tank... My point is check ur car for leaks