Car starts and dies immediately. P0171 (too lean)
 

Hi guys, I'm hoping somebody has some advice on my issue.

Basic background: 2014 FRS, totally stock. Around 55,000 miles. ~8 month old battery. No issues previously.

I drove the car home from work on Thursday, got gas near my office (93 octane of course), drove the rest of the way home (~20 miles) and everything was totally normal. I didn't drive anywhere yesterday.

Half an hour ago I hopped in the car to go somewhere. It cranked fine, started for an instant then it sputtered out and died. I tried a couple more times with similar results. Once it hung on a little longer and the engine sounded really rough and the car started shaking before dying.

I plugged in my OBDII reader and got one Pending Fault code P0171: Powertrain System too lean (Bank 1).

Searching around it looks like a lot of people getting this error code have custom tunings or forced induction, which isn't the case for me.

Any ideas? Anybody seen anything similar?

What does the maf look like? What were the last few things you touched under the hood?

https://demos.starbase7.net/t3Portal...00WC30M6X.html

I checked the MAF sensor, qualitatively it looks ok. It's clean, not clogged up with any junk.

Nothing has been touched under the hood very recently. I bled the brakes in September, and replaced the battery and oil change a little before that. I replaced the air filter around the same time, I don't remember exactly when.

Thanks for the link, good info.

Look for the least exotic shit and work your way down. Good luck.

Yep, ....... I reckon I'd check the PCV connections and if all looks good, then clean the MAF thing.


humfrz

PS......Bubba says to unplug the battery then wait 23 seconds and plug it back in ......he has no idea why he suggests that ......:iono:

HOW TO PROCEED WITH TROUBLESHOOTING


DIAGNOSTIC CODE TROUBLE CHART

Cleaned the MAF sensor, didn't do anything.

We were able to keep the engine alive for a few seconds with starter spray which would seem to indicate it's not a spark plug problem. Combined with the "too lean" error code it points to a fuel delivery problem.

We can hear the pump priming (or doing something) when the key is turned so presumably that is ok.

Took the fuel pump/filter assembly out and looked at it. The filter embedded in the plastic sleeve is brownish looking, I don't know if that's normal. The mesh thing below the pump is also pretty brown (see pic below). Looking at some pictures and videos other people's look white, but maybe that's just when they're brand new.

https://i.imgur.com/pfTUdwr.jpg

Do these cars have an inline fuel filter or just the one in the tank?

Just that one in the tank. It's not the fuel filter. Clogged fuel filter causes starvation at higher fuel demand, not idle.

You got gas and then the car wouldn't start. I'd pump the tank out and put 5 gallons of fuel from a different station in it. Bad fuel can absolutely cause P0171. Unless the air intake is completely removed post MAF the engine would still run.


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I'd like to hear it cranking and not starting. Post a video

That does seem like potentially the simplest problem.

The audio isn't very good, I will get somebody to help me record a better one.

https://youtu.be/w19f9Ayy6tM

OK, so you have compression. Some security systems will kill fuel, that's what it sounds like. But that's a guess, you need to find out if it's not getting spark or not getting fuel and work your way back