Code P0171?

Hi,

If there are no vacuum leaks, the next thing to check is the fuel pressure. If the pump is weak, it can cause a lean fuel mixture.

Here is a link that explains how in general to check pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

If you look below, I attached the manufactures directions for testing specific to this vehicle. The directions include the pressure specifications.

You will need a fuel pressure gauge. Often times, a parts store will lend one to you if needed.

Let me know if this helps, if you have other questions, and what you find.

Take care,

joe

See pics below.

Thanks will check and keep you posted.

Good day, the fuel pressure was low, I replaced the fuel pump and no more P0171 code after driving for a few days now.
One other thing I found since a while back gas consumption is kind of high. I service injectors, new spark plugs, throttle and idle air valve service. And other ideas.

Hi,

There is a chance the excessive fuel usage was caused by the computer trying to compensate for a lean mixture. You may find it increases now that it is running properly.

If it doesn't, make sure the coolant temperature sensor is sending the proper signal to the PCM. If it is off, it can affect the air/fuel mixture. Also, make sure the air filter is clean, and no brakes are dragging.

Let me know how things work out for you or if you have other questions.

Take care,

joe

Thanks will keep you updated.

Good day, after about a week of driving the car, gas mileage is not too good and still a few cranks before starting. I did a scan and code P0327 is showing. I inspected the wire harness, and it looks good. Could you send me testing procedure for the knock sensor?

Hi,

I attached the directions from my manual below. Note that it really isn't a test procedure of the present sensor. Instead, they indicated that you should replace it with a known good one to check. Ugh! Take a look and let me know your thoughts.

If you have a live data scan tool, you should be able to check the sensor parameters when the engine is at operating temperature.

Are you hearing any valve ping or knocking?

Take care,

Joe

See pic below.

I'm hearing valve pinging, I don't have one to try, so I will replace the sensor, I cleared the code and I drove the car so will check to see if the code comes back. But will this cause long cranking to start an high gas consumption. I got 300 km on a full tank of gas.

Hi,

It could cause all that you mentioned. The sensor is used to fine-tune ignition timing to allow the engine to run more efficiently.

If you have a chance, let me know how things work out for you.

Joe

Good day, I replaced knock sensor, no more codes. Still getting a few cranks before start up.Will monitor an let you know.

Hi,

Thanks for the update. I'm glad you got it taken care of. As far as the delay starts, let me know if it worsens. We could have fuel pressure drop off causing that to happen.

Let me know. If I don't hear back from you, I wish you and your family a Merry Christmas.

Take care,

Joe

Hi, I already replaced the fuel pump, and same issue. Will double check the fuel system and see.

Hi,

If you have a leaking injector, it will cause pressure to drop off. If you have a chance, let me know what you find.

Joe