Quote:
Originally Posted by gio240sx
alright so my 97 s14 won’t psss smog, keeps throwing a p0171 code when the check engine light turns on and the engine bogs hard, car shut off on me at a stop sign about 1 minute after leaving the smog shop too. here’s a photo of the paper from the shop if anyone could know the culprit. already replaced the MAF sensor the o2 sensor and i don’t see any leaks anywhere. here’s a photo of the smog sheet if anyone could help i’d appreciate it https://ibb.co/dQthtzw |
P0171 Fuel Injection System Function (Lean Side)
Detected when: Fuel injection system does not operate properly. The amount of mixture ratio compensation is too large (ratio is too lean).
Check Items (Possible Cause):
-Intake air leak
-Front heated oxygen sensor
-Injectors
-Exhaust gas leak
-Incorrect fuel pressure
-Lack of fuel
-Mass air flow sensor
You've already replaced MAF and O2 sensor, so it's probably one of those other causes. Trouble shooting steps begin at page EC-143 in this document:
http://www.nicoclub.com/FSM/240sx/1997/ec.pdf
On a car that old, I'd fully inspect the intake boots & hoses (like take them off the car and really inspect them). Every one of my cars has had a torn boot or a cracked hose that wasn't easy to spot from a basic "visual inspection." The other one that actually happened to my 97 was the EGR hard pipe was cracked and needed to be replaced, was easy to hear that exhaust leak however. Other things could be faulty/clogged injectors or a failing fuel pump even. Looks like you're up over 250k miles, stuff just wears out.