engine check light after air filter change

[quark_man]

Hey.
While changing the air filter I forgot to plug in the sensor. While driving I got the engine light. When I popped the lid, there it was. I plugged in, but the light is still on. How do I get rid of it? Do I unplug the computer for a certain period of time? Do I need to go to a shop for them to scan and erase the code? Please help.

[BroncoJoe19]

Most likely after a half a dozen starts and warmups or ten mile trips, it will clear itself.

[vindctar]

Disconnect the negative battery terminal to reset the PCM .

Originally Posted by quark_man

Hey.
While changing the air filter I forgot to plug in the sensor. While driving I got the engine light. When I popped the lid, there it was. I plugged in, but the light is still on. How do I get rid of it? Do I unplug the computer for a certain period of time? Do I need to go to a shop for them to scan and erase the code? Please help.

[GraybeardAv]

Don't forget the vacuum hose on the back side of the intake tube.

[quark_man]

thanks. I did disconnect the bat.

[BroncoJoe19]

It is my understanding that one should NOT disconnect the battery to clear codes.
Does it work? Yes, but it also clears out the numbers that the computer has used and stored as a part of its adaptive strategy.

Adaptive Strategy
Now this one is a little complex. EEC likes to toy with the fuel ratio at random. It does this to run complex math equations. She is calculating how much fuel is required to reach certain lean or rich states. Why you ask? Because playing this cat and mouse game with the fuel ratio allows us to fine tune the engine parameters in other strategies. Confused yet? EEC cuts back on the injectors for a spit second and counts how long it takes for the HEGO to report back a lean environment. EEC leans and enriches at different amounts and get back different numbers. These numbers tell EEC if the engine needs a tune up, or if you’ve added a performance parts and allows us to actually alter the fuel amount delivered. What do we do with those numbers EEC collected? Well there is a Table called “Adaptive Fuel Table” (makes sense huh?) This table is used as a multiplier, it is held over the master load table. It then multiplies each number in the master table to get a better control of fuel delivery over time. In a computer that has been just connected to the battery it is full of “1’s”, if you multiply the master table by “1″ you get the same number. I’m not good at math and I understand it, 14.7:1 X 1 = 14.7:1, simple!. After many days of driving on the highway it begins to fill with multipliers like “1.2’s” and “0.9’s”, which will alter the master table. Don’t believe me? 14.7:1 X 1.2 = 17.6:1, and 14.7:1 X 0.9 = 13.3:1, and we just fine tuned our fuel curve without doing anything special. Isn’t that cool? Well not always, this entire technology depends on the Oxygen Sensors being fresh, clean, new, and in good condition. And it can’t be responsible for displacement changes, cam changes, or other big performance add-on’s. This technology is only meant to keep EEC on the same level as an ageing engine with diminished performance. It is not meant to be relied upon for performance engine tuning!

Ford Fuel Injection » Strategies

[mark v]

Yes never disconnect the battery just to remove a code, either use a reader to erase the code or after 25+ full ignition cycles it will erase its self.

[vindctar]

Roger that mark v, but I learnt this "dirty trick" here (see quoted text). Desperate times, desperate measures?

Originally Posted by phantom_smack

Try spraying some intake cleaner down the throttlebody to free up the intake runner.You may have to disconnect the maf sensor to run it with the intake hose disconnected.Then disconnect the battery to clear codes and go for a test drive.

[BroncoJoe19]

The adaptive fuel control strategy is designed to compensate for variability in the fuel system components. If, during normal vehicle operation, the fuel system is detected to be biased rich or lean, the adaptive fuel control will make a corresponding shift in the fuel delivery calculation.
Whenever an injector or fuel pressure regulator is replaced, keep alive memory (KAM) should be cleared. This is necessary so the fuel strategy does not use the previously learned adaptive values.

[Flyingjackal456]

hmmm, my van has good days and bad days with the stalling issue. I've noticed that the days it stalls are the days it also has less power. (Weak idle has weak 'punch' when accelerating) The days it doesn't stall, it doesn't hesitate and it has better power throughout the power curve.

The O2 sensors are original, but I really don't feel like spending money... What are my chances that they still work right at 251,000 miles? How many sensors are there for O2 and how can I check the EGR system? What's the cheapest price on decent O2 sensors? My guess is motorcraft all the way?