I’ve got a 1997 Hyundai Elantra wagon which I can obtain for basically nothing… high miles… about 192kmi. The CEL is on and the owner had the code read… it came back as a problem with the EVAP. I had a hard time starting it, and it only started when I gave it a little gas while cranking it on the pedal. Even after it had ran for a few minutes, the exhaust still smelled a bit on the rich side, and its getting not so great MPG.
My questions:
1. What does the EVAP code mean? Is it something to do with the evaporative emissions system?
2. Given the lousy MPG, hard starting, etc, any ideas on what needs to be replaced and $$ involved?
I’d look for any broken or cracked vacuum lines. Also, try replacing the gas cap. The EVAP system is basically controls to prevent fuel vapors from being leaked to the air. This includes a vacuum line to a charcoal canister under the hood that captures fuel vapors, and additional lines that run to the fuel tank to suck out the vapors there. There is a purge valve that is controlled by the computer to keep the canister from saturating. This valve will pull excess vapors from the canister to the engine to be burned. If the gas cap is leaking air, then it will set a code. If there are vacuum leaks in the evap system overall, then this will cause some of the other symptoms you’re having, since air is entering the intake that is by-passing the Mass Air Flow Sensor. The computer is, therefor, trying to compensate for the extra air, but has no idea how much is getting in, because it is unmonitored by a sensor.
Also, if vacuum drops, then the fuel pressure regulator could be forcing the pressure too high, causing the rich smell and poor mileage. Some of these newer cars have so few vacuum lines, that I would not be surprised if the fuel pressure regulator line is also connected to the evap system. A fuel pressure check should also be done.
Another thought is a bad intake gasket somewhere. This could also cause these problems with letting in unmonitored air. Also, check the condition of the intake hoses. They should be sound, with no cracks or breaks.
There is more than one code involved with the EVAP and we do not know what that existing code is.
The codes related to EVAP have to do with the gas tank venting system, canister, etc. so you would have to know the specific code, get the manual, and troubleshoot it.
That being said, the hard starting, lousy MPG may not have anything to do with the EVAP system. If it’s that bad I would be leaning towards a leaking fuel pressure regulator; maybe.
There’s just not enough info to get too deep into this car, but considering a price at near nothing it’s definitely worth getting and dinking around with.
Chances are the problem(s) are not as serious as one might think; and 192 KMs is not that high of a mileage IMHO.
You need to have the codes read again. Some places will read them for FREE. Try Autozone or Advanced Auto Parts. Get the exact code (like P0123) not just their translation into English and post it back here.
Regarding warning lights:
-
if the coolant temp light comes on, shut off the engine ASAP
-
if the oil warning light comes on, shut off the engine ASAP
-
if a FLASHING MIL/CEL comes on, shut off the engine ASAP
ASAP means driving to the berm of the highway right now and not waiting for the next exit.
But if the MIL/CEL is not flashing, then it’s not an urgent indicator.