So this morning I noticed my check engine light came on on my way to work. There were about 4-5 codes, One saying the system was too lean, and the others were cylinder misfires. Any idea what is causing this? This is the second time I've noticed this in the last two months, both in the morning, and on those few morning that I don't even push the car.
Yes I have a SS tune and lightened pulley. No I haven't talked to Steven yet. We used the coilpacks from the Long block I bought which had 1200 miles on it, now there's about 5,000 miles on them. When I got tuned my rear o2 sensor was going bad, could this be do to it being completely gone now? I've noticed a drop in my MPG too.
Well I didn't go WOT this morning, but I did on my way to lunch and I could smell Gasoline! It also stalled on me at the stop sign while I was rolling, yes the clutch was engaged.
Mine stalls EVERY time I roll to a light after popping the clutch in Neutral. I'm troubleshooting it now. I've been told boost/vac leak but I doubt it. I think my IACV is clogged/dirty. I will try to update this thread too to help you out. (However I throw zero codes).
I would think the lean condition would be attributed to the O2 but the misfires I am not too sure...I get them but usually when beating the everliving shit out of my car. Thank god for 6mt I can do that now.
Ok, cel came back on. Its showing a p0171 code. System too lean (bank 1). I know for a fact I have a preturbo leak, could it be it finally opened up enough to effect it? I am noticing gas dumping when I am in boost. Looks like I'll be limping around at 1/4 throttle until this gets resolved. Aside from my gas needle rapidly dropping the car is running fine.
ENGINE (DIAGNOSTICS)(H4DOTC) > Diagnostic Procedure with Diagnostic Trouble Code (DTC) DTC P0172 SYSTEM TOO RICH (BANK 1) DTC DETECTING CONDITION: • Two consecutive driving cycles with fault • GENERAL DESCRIPTION TROUBLE SYMPTOM: • Erroneous idling • Engine stalls. • Poor driving performance CAUTION: After repair or replacement of faulty parts, conduct Clear Memory Mode and Inspection Mode . STEP CHECK YES NO 1.CHECK EXHAUST SYSTEM. Are there holes or loose bolts on exhaust system? Repair the exhaust system. 2.CHECK AIR INTAKE SYSTEM. Are there holes, loose bolts or disconnection of hose on air intake system? Repair the air intake system. 3.CHECK FUEL PRESSURE. WARNING: • Place “NO FIRE” signs near the working area. • Be careful not to spill fuel on the floor. 1) Release the fuel pressure. (1) Disconnect the connector from fuel pump relay. (2) Start the engine and run it until it stalls. (3) After the engine stalls, crank it for 5 more seconds. (4) Turn the ignition switch to OFF. 2) Connect the connector to fuel pump relay. 3) Disconnect the fuel delivery hose from fuel filter, and connect fuel pressure gauge. 4) Install the fuel filler cap. 5) Start the engine and idle while gear position is neutral. 6) Measure the fuel pressure while disconnecting pressure regulator vacuum hose from intake manifold. WARNING: Before removing the fuel pressure gauge, release fuel pressure. NOTE: If the fuel pressure does not increase, squeeze fuel return hose 2 to 3 times, then measure fuel pressure again. Is the measured value 284 — 314 kPa (2.9 — 3.2 kg/cm2, 41 — 46 psi)? Repair the following items. Fuel pressure too high: • Clogged fuel return line or bent hose Fuel pressure too low: • Improper fuel pump discharge • Clogged fuel supply line 4.CHECK FUEL PRESSURE. After connecting the pressure regulator vacuum hose, measure fuel pressure. WARNING: Before removing the fuel pressure gauge, release fuel pressure. NOTE: • If the fuel pressure does not increase, squeeze fuel return hose 2 to 3 times, then measure fuel pressure again. • If out of specification as measured at this step, check or replace the pressure regulator and pressure regulator vacuum hose. Is the measured value 206 — 235 kPa (2.1 — 2.4 kg/cm2, 30 — 34 psi)? Repair the following items. Fuel pressure too high: • Faulty pressure regulator • Clogged fuel return line or bent hose Fuel pressure too low: • Faulty pressure regulator • Improper fuel pump discharge • Clogged fuel supply line 5.CHECK ENGINE COOLANT TEMPERATURE SENSOR. 1) Start the engine and warm-up completely. 2) Read the data of engine coolant temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedure, refer to the “READ CURRENT DATA FOR ENGINE”. • General scan tool For detailed operation procedures, refer to the General Scan Tool Instruction Manual. Is the temperature more than 60°C (140°F)? Replace the engine coolant temperature sensor. 6.CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE. 1) Start the engine and warm-up engine until coolant temperature is greater than 60°C (140°F). 2) Place the shift lever in neutral position. 3) Turn the A/C switch to OFF. 4) Turn all accessory switches to OFF. 5) Read the data of mass air flow and intake air temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedure, refer to the “READ CURRENT DATA FOR ENGINE”. • General scan tool For detailed operation procedure, refer to the General Scan Tool Instruction Manual. Is the measured value within the followings? Ignition ON: 73.3 — 106.6 kPa (550 — 800 mmHg, 21.65 — 31.50 inHg) Idling: 24.0 — 41.3 kPa (180 — 310 mmHg, 7.09 — 12.20 inHg) Replace the mass air flow and intake air temperature sensor. 7.CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR. 1) Start the engine and warm-up engine until coolant temperature is greater than 60°C (140°F). 2) Place the shift lever in neutral position. 3) Turn the A/C switch to OFF. 4) Turn all accessory switches to OFF. 5) Open the front hood. 6) Measure the ambient temperature. 7) Read the data of mass air flow and intake air temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: • Subaru Select Monitor For detailed operation procedure, refer to the “READ CURRENT DATA FOR ENGINE”. • General scan tool For detailed operation procedure, refer to the General Scan Tool Instruction Manual. Subtract ambient temperature from intake air temperature. Is the obtained value −10°C — 50°C (14°F — 122°F)? Contact your SOA Service Center. Check the mass air flow and intake air temperature sensor.
code P0171 may mean that one or more of the following has happened: The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry. There could be a vacuum leak downstream of the MAF sensor.
On the fuel side MAYBE: fuel fill cap may need to be replaced, driver's side access panel short in the wires at the fuel tank, wires shorting out at the fuel tank pressure sensor, clogged fuel filter, clogged injector
Thank you everyone for your suggestions, I think I found the problem... a little hose on the manifold came lose, time to zip tie that bitch down! How much does an o2 sensor costs?
If its the one that goes to the fpr then you will go lean under boost as the fpr will not be able to compensate for the boost. If there is any slack in the line I would cut a little off the end and then zip tie it.
FPR? What is that? It was a tiny vacuum flange tube coming directly off of the manifold. I can hear another leak closer to the turbo, I wonder if its the plug on the TGV, we did plug it with jb weld and then put the sensors back on the side. One day this week I'll pull the sensor off and feel for the plug.
Is it poping and backfiring when it is more than quarter throttle? if it is we need to GTG and ponder cause mine does it every once and a while. Not sure as to what is causing mine maybe bad/old coils or wrong sparkpugs but I do notice that my car runs realy rich all the time. I am going to hook up air/fuel ratio gauge tomorrow. When mine does it ,it feels like it ran out of fuel or the maf sensor is not hooked up.
Mine backfires once in a while at or around idle no codes, nature of the beast once you un-strangle it. Misfires should be addressed though! Mine sounds very happy just talken' a little! Reminds me of my69 Chevelle SS just talken' lean at idle but open that 396 up & gettf out of the way!
The FPR is the fuel pressure regulator. The FPR has a vacuum/boost line to it so as the boost rises it can add fuel pressure. The stock regualtor runs 43 psi and for each pound of boost it adds one pound of fuel pressure. If it didn't, the fuel injector wouldn't be able to inject as much fuel or atomize the gas as well. Crushing the top of the fpr to increase the load on the spring inside is a common mod to stretch the capacity of the injectors. My FPR is modified and runs around 50 psi intead of 43.