FIXED: Return of the P0171 and P0174

[upallnight]

So the video that you posted with the automatic trans light coming on was this before you replaced fuel pump or after?

[diddy0071]

Originally Posted by upallnight

So the video that you posted with the automatic trans light coming on was this before you replaced fuel pump or after?

Afterwards.

[bcredliner]

Could it have been junk in the tank that caused the problem last time and is doing the same thing to the replacement pump? Did you check the tank when you replaced the pump and/or check the pump screen on the old pump to know if it was clear? Filling the tank from anywhere close to empty stirs up anything that shouldn't be in the tank. Could it be the pump was a symptom rather than the root cause? Did you purchase gas at the same place as last time?

[diddy0071]

Originally Posted by bcredliner

Could it have been junk in the tank that caused the problem last time and is doing the same thing to the replacement pump? Did you check the tank when you replaced the pump and/or check the pump screen on the old pump to know if it was clear? Filling the tank from anywhere close to empty stirs up anything that shouldn't be in the tank. Could it be the pump was a symptom rather than the root cause? Did you purchase gas at the same place as last time?

It could have been, but the pump screen looked ok, no sediment, and the gas tank looked clean without sediment. I pumped 21.801 Gallons (gotta love my gas tracker log on my iphone) so it wasn't too dry. The pump definitely be the symptom not the root cause, but what can I do? Drop and replace the tank?

[upallnight]

Originally Posted by diddy0071

Afterwards.

So these are new codes. Just because the codes cleared up doesn't mean the problem went away. The auto trans light came on when you were driving aggressively. If you are still driving aggressively and the light hasn't come come on fine, but if you change your driving habit to drive more conservatively that mean the problem could still be there if you starts driving aggressively again. I would not call this a fix.

[diddy0071]

Originally Posted by upallnight

So these are new codes. Just because the codes cleared up doesn't mean the problem went away. The auto trans light came on when you were driving aggressively. If you are still driving aggressively and the light hasn't come come on fine, but if you change your driving habit to drive more conservatively that mean the problem could still be there if you starts driving aggressively again. I would not call this a fix.

The P0171 and P0174 are new codes.

[diddy0071]

Timeline:

Vehicle was broken down July 5th, 2013 at 212,619 miles.

Vehicle up and running July 15th, 2013 with replacement fuel pump.

Fuel filter and fuel rail replaced July 21st, 2013. Mileage est: 212,859

Road trip to Fresno, CA on 7/23-7/25, over 500 miles put round trip, 2 tanks of gas.

Vehicle suffers issues week of 7/29-7/31 with starting.

8/4-Vehicle has sluggish performance issues at 213,535

About ~950 miles from last breakdown to this issue.

[upallnight]

Get some starting fluid and spray it around the injectors. If the engine pick up speed you found the source of your vacuum leak. As always have a fire extinguisher nearby.

GL

[bcredliner]

My thinking is the transmission related codes were always there, are false error codes somehow caused by the pump issue or new codes indicating a new problem.

My assumption is that you verified, by driving hard and easy, that the replacement pump eliminated the symptoms you were having? And, as I understand the current codes were not there when you checked for codes before?

If that is the case, I suggest the first step is to check fuel pressure as the symptoms are the same as before you changed the fuel pump. I asked about junk in tank because that would be higher probability than the replacement pump doing the same thing, especially since it worked fine for a reasonable amount of time.

The less likely possibility is that the pump performance was a symptom caused by something else not associated with the replacement. That would mean the symptoms went away even though you addressed the wrong cause, IMO that doesn't make sense.

[diddy0071]

Originally Posted by bcredliner

My thinking is the transmission related codes were always there, are false error codes somehow caused by the pump issue or new codes indicating a new problem.

My assumption is that you verified, by driving hard and easy, that the replacement pump eliminated the symptoms you were having? And, as I understand the current codes were not there when you checked for codes before?

If that is the case, I suggest the first step is to check fuel pressure as the symptoms are the same as before you changed the fuel pump. I asked about junk in tank because that would be higher probability than the replacement pump doing the same thing, especially since it worked fine for a reasonable amount of time.

The less likely possibility is that the pump performance was a symptom caused by something else not associated with the replacement. That would mean the symptoms went away even though you addressed the wrong cause, IMO that doesn't make sense.

Possibly, but there are no transmission codes currently. Unless I download a BMW specific software to check.