2000 ECHO Check Engine On code P0171 System Too Lean

[sj22]

Greetings:
First owner, 192000 miles. Check engine light came on during last winter, I put fuel injector cleaner with gas and it went away for a while. It came back on, if i reset, I can drive for about 50 miles before it comes back on line. Also, may be two or three times a week, when moving after a stop, the vehicle stalls, i have to take the feet of the gas pedal and give gas again.

I called up the dealer asking for fuel filter and fuel injector parts prices. Fuel filter is in the gas tank and not meant to be replaced. The fuel injector I was told 4 x $155 each.

For diagnostics they need $100

See attached, I was able to clean sensor 1. I could not unscrew sensor 2, the screw is rusted, plus there is no room to get a longer screw driver and turn

Thanks for your help
-Shaw

[sj22]

here is the image

http://www.hotlinkfiles.com/view/full/1713883_uvwjy

[toyomoho]

For some reason the engine A/F ratio is running lean. The ECU is compensating for this by adding extra fuel (running the system richer then the ECU states the engine should be when normal).

Issues that can cause this code are: Exhaust or air intake leaks, low fuel pressure, plugged injectors, engine coolant sensor, O2 sensor (Bank 1 or 2, Sensor 1), MAP or MAF sensor.

Typically if clogged injectors the engine idles and runs rough.

You cleaned the MAF sensor? Disconnect the electrical connection to the sensor and determine if the engine no longer stalls when you press on the gas.

From the photo not sure what the number 2 sensor is.

[sj22]

toyomoho,

I will disconnect the MAF sensor electrical connection and see if the engine runs ok.
Currently it stalls once in a while

After MAF sensor troubleshooting, how do I determine if I have low fuel pressure or plugged injectors ?


Thanks

[toyomoho]

For fuel pressure need to install a pressure gauge.

Injectors are more difficult to test but don't think this is your problem.

If you reset the CEL it will always take some time to return because the computer needs to run through a diagnostic test. As such adding the injector cleaner may have done nothing.

Suggest you pick up a Haynes manual on this car or post to the various Yaris only clubs on the internet that might have more details on this specific car.

[Nad1370]

Almost 200k?
I'd also check a leak at the intake manifold gasket.
It's just rubber and get gets brittle and leaks over time.
Have the engine running and spray some carb cleaner around the manifold gasket.
If engine idle changes...theres your problem.

[sj22]

Nad1370,
Done the carb cleaner, didn't notice a change
I will check the intake manifold gasket.

toyomoho
is it easy to install a pressure guage. any idea on rough cost of the guage

-Shaw

[sj22]

Nad1370,
how do I check the intake manifold leak, just putting hand around and feeling for air ? is there another way ?

Thanks
-Shaw

[Nad1370]

Originally Posted by sj22

Nad1370,
how do I check the intake manifold leak, just putting hand around and feeling for air ? is there another way ?

Thanks
-Shaw

Spraying carb cleaner while it's running is the best way to find an intake leak.
As of your findings, the idle didn't change at all. Did you take the plastic cover off the valve cover to get a better spray on top of the manifold?

You mentioned cleaning the MAF and still had the problem.
I'm just thinking it's beyond cleaning and needs a new one. Although I can't say for sure w/out diagnosing it with a scanner or swapping it with a known good MAF sensor.

[sj22]

nad1370,

I will call the dealer and find if i can get a MAF sensor with option to return in 3 days, if it don't solve the problem.
Can i get MAF sensor from any place other than the dealer.

Also, could you pls confirm that the component marked #1 in the image below is indeed the maf sensor.

http://www.hotlinkfiles.com/view/full/1713883_uvwjy

Thanks
Shaw

[Nad1370]

Yes, image #1 is the MAF sensor.

If you have the option to return the part w/ in days. Then that's the best thing to do.
Good luck !

[new echo owner]

Try taking the MAF sensor and clean it with electrical contact cleaner, and see if that help your problem. I had the same code, cleaned it with the cleaner, has not come back on yet.

Good Luck,

N.E.O.

[sj22]

Hello Everyone,
I was able to pick up a used MAF sensor (from a totaled 2003 echo 27,000 miles). Car runs great now - no check engine.

Thanks for your help!!!!

PS - Moderator - Do I need to do anything to close this thread?

[drshawn]

I am having the same problem with my 2000 Toyota Echo. My check engine light is on. Last year the mechanic did his check and had me by an O2 Sensor. The check engine light still came on.

This weekend i went to Auto Zone and bought some MAF cleaner. I was told to spray the cleaner on the thin wires inside the hole. So I sprayed it several times. The instructions told me the check engine light should go off at the next system check....

My question is the little part that is labeled #1 in the photo. When I pull off that part, is that the sensor? And am I supposed to spray that as well?

Does that make sense?

Thanks

Shawn

[sj22]

drshawn
yes #1 is the maf sensor. You can pull that off and try to clean it. But i think you will be better of replacing it. I paid $50 for a used one

Rgds
Shaw