Massive Flow Sensor Problem-2002 Accent

Just heard from my buddy with the 2001 Accent, the one with the
defroster problem. He's not worried about the defroster anymore;
the Accent is now barely running. He was trying to pass somebody
(!) the other day and the "Check Engine" light, which has been on
for a month or so, started flashing and the car lost power.

He took it to AutoTechPartsAdvanceSpeedZone or something, and
they put the scan tool on it. He doesn't have the codes, but they
said:

"Mass Air Flow Sensor"

"Misfire Cylinders 1, 2, 3"

"Main Catalyst Below Threshold"

"Bank 1"

OK, it's a little garbled... but MAF sensor bad, causing bad
mixture, misfires and emission control problem wouldn't seem too
far off the mark at first glance.

However, it's not my area of expertise. I would welcome any
advice or suggestions as to what to check or how to proceed.

Right now, the course of action if I don't get more info either
here or on Google is to replace the MAF. Unless I find a dead
mouse in the air filter or something. This car has not had
regular maintenance. He wants to drive it to Florida next week....

The parts place wanted to know what engine he has; the VIN is
KMHCF35GX1U12xxxx. If nobody knows off the top of their head, I
will try the Hyundai site but it only works with Windows so is
not simple for me the next few days.

Thanks to anybody for assistance!

PB

 

Plague Boy wrote:

<I'm not going to snip, just this once>
The car seems to be fixed. He couldn't get the MAF until Tuesday,
so we decided to go ahead with the new plugs, wires, and air
filter that I have been recommending for *months*.

Air filter was very dirty; vacuumed out the box while it was
open because it was full of debris. Sprayed the MAF with "Zero
residue cleaner" for tape decks and sprayed the contacts of the
connector (looked OK) with contact cleaner.

Removed the old plugs (looked old, but not too bad) and replaced
with new Bosch Platinum Plus. Went smoothly.

Two ignition wires broke when I removed them (connector remained
on spark plug) and replaced with four new wires.

Fired it up, and it seemed better. So we drove over to
AdvanceSuperCenterPartPlaceZone to pick up oil. The MIL was on,
but steady, on the way over. Ran the scan tool, and the MAF code
was gone, but the ones for the misfire(P0300, 301 etc.) were
still stored. Cleared the codes, and the MIL went out and stayed out.

So I changed the oil, because there was something...odd...about
the oil. I thought maybe it was diluted with gas, which is what
the guy at the parts place said something about.

So, since I didn't try the engine after each step, I don't know
which thing actually fixed the problem. My guess is the wires
were bad. Still, all "routine maintenance" and good to be done.
Friend is very happy to not blow $100+ on MAF and says car runs
better than ever since he bought it. I'm happy, because I have a

 

I'm betting the catalyst efficiency code will come back. Driving a car
while the engine is badly misfiring (indicated by a flashing check engine
lamp) will typically cause catalyst damage.

 

Well, the MIL has stayed off as of today....we'll see what
happens. He's going to drive the car to FL Thursday.

Thanks for the reply.

PB

 

He picked me up and took me to the airport Dec. 19th. Check
engine light was on, I noticed. I presume he's still in FL but I
will see how it went when he gets back and post anything interesting.

PB