CEL from humidity?

taejinah · 07-24-2007, 06:53 PM

I've had my injen cai installed for over a year now. Never had a single CEL til now...

scanned it and found it to be P0172 system running too rich. I guess it was only a matter of time before I got it? I just think it's weird how it never showed up until recently.

I reset my ECU, hoping it would go away. It came back within 12 hours.

I've been reading up on possible causes for P0172 and it could be a multitude of things. I'm leaning toward it not just being the cai since mine has had no problems for such a long time.

One thing I was wondering though, could humidity cause the car to throw this kind of CEL?

The only thing that changed before I got this light was that I was driving in very humid weather. The night my CEL came back after I reset it, it was also very, very humid.

iknowmysh1t · 07-24-2007, 07:04 PM

DTC P0171: Fuel System Too Lean

DTC P0172: Fuel System Too Rich

NOTE:

* Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
* If any of the DTCs listed below are indicated at the same time as DTC P0171 and/or P0172, troubleshoot those DTCs first, then recheck for P0171 and/or P0172.

P0101, P0102, P0103: Mass air flow (MAF) sensor
P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor
P0133,P1172,P1157,P2195,P2238, P2252, P2AOO: Air fuel ratio (A/F) sensor (Sensor 1)
P0134, P0135: Air fuel ratio (A/F) sensor (Sensor 1) heater
P0137,P0138,P0139,P2270,P2271: Secondary HO2S (Sensor 2)
P0141: Secondary HO2S (Sensor 2) heater
P2646, P2647, P2648, P2649: VTEC system
P0400,P0401,P0404,P0406, P2413: Exhaust gas recirculation (EGR) system
P0443, P0496: EVAP canister purge valve

1. Check the fuel pressure. Is the fuel pressure OK? YES - Go to step 2. N0 -

o If the pressure is too high, replace the fuel pressure regulator, then go to step 7.
o If the pressure is too low, check the fuel pump, the fuel feed pipe and the fuel filter. If they are OK, replace the fuel pressure regulator, then go to step 7,

2. Check for vacuum leaks at these parts:

o PCV valve
o PCV hose
o EVAP canister purge valve
o Throttle body
o Intake manifold
o Brake booster
o Brake booster hose
o Air Intake duct

Are the parts OK?

YES - Go to step 3.

NO - Repair or replace parts with leaks, then go to step 7.

3. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
4. Check for these conditions:

o ECT SENSOR 1 above 176 F (80 degrees C)
o Transmission in neutral
o All electrical loads off

5. Monitor the ENG SPEED in the DATA LIST with the HDS, and hold the engine speed at 4,500 rpm . Once the engine speed is met, hold the accelerator pedal steady for more than 10 seconds . Did the engine speed vary more than 100 rpm from 4,500 rpm ? YES - Repeat step 5. NO - Go to step 6.
6. While holding the engine speed at 4,500 rpm , check the MAF SENSOR in the DATA LIST with the HDS. Is there about 14-20 gm/s ? YES - Check the engine valve clearances and adjust if necessary. If the valve clearances are OK, replace the injectors, then go to step 7. NO - Replace the MAF sensor/IAT sensor, then go to step 7.
7. Turn the ignition switch ON (II).
8. Reset the ECM with the HDS.
9. Do the ECM idle learn procedure.
10. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle.
11. Test-drive under these conditions:

o ECT SENSOR 1 above 176 degrees F (80 degrees C)
o Transmission in neutral
o All electrical loads off

NOTE: DTC P0171 and/or P0172 may take up to 80 minutes of test driving to set. Using the HDS, monitor the long term fuel trim (LT FUEL TRIM) or the air fuel feed back average (AF FB AVE). If the long term fuel trim/air fuel feed back average stays within 0.80-1.25 , there is no problem at this time.

12. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0171 or P0172 is indicated, go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Troubleshooting is complete.

iknowmysh1t · 07-24-2007, 07:31 PM

bump for info?

taejinah · 07-25-2007, 01:20 AM

thank you soooooo much!

iknowmysh1t · 07-25-2007, 02:34 AM

no problem

taejinah · 07-25-2007, 09:09 PM

i dont think ive seen this posted anywhere before pertaining to the engine running rich scenario (especially for those with the injen cai).

someone should sticky this somewhere? unless of course it's already somewhere.. and im just blind -_-

taejinah · 07-25-2007, 09:11 PM

after reading through that I decided it might be my intake manifold cuz i installed the hondata IMG a couple months ago. I've tried to re tighten all the bolts and reset the ecu... so far about a compiled hour or so of driving and cel hasn't come back yet... i also regrounded the fuel rail just in case that might be the problem.

If cel comes back, I'll have to take it to the dealership to check all the fuel stuff

hopefully not though.

07-24-2007, 06:53 PM	#1 (permalink)
taejinah Senior Member Join Date: Mar 2006 Posts: 399 iTrader: 0 / 0%	CEL from humidity? I've had my injen cai installed for over a year now. Never had a single CEL til now... scanned it and found it to be P0172 system running too rich. I guess it was only a matter of time before I got it? I just think it's weird how it never showed up until recently. I reset my ECU, hoping it would go away. It came back within 12 hours. I've been reading up on possible causes for P0172 and it could be a multitude of things. I'm leaning toward it not just being the cai since mine has had no problems for such a long time. One thing I was wondering though, could humidity cause the car to throw this kind of CEL? The only thing that changed before I got this light was that I was driving in very humid weather. The night my CEL came back after I reset it, it was also very, very humid.

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07-24-2007, 07:04 PM	#2 (permalink)
iknowmysh1t Senior Member Join Date: Mar 2007 Posts: 970 iTrader: 0 / 0%	DTC P0171: Fuel System Too Lean DTC P0172: Fuel System Too Rich NOTE: * Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. * If any of the DTCs listed below are indicated at the same time as DTC P0171 and/or P0172, troubleshoot those DTCs first, then recheck for P0171 and/or P0172. P0101, P0102, P0103: Mass air flow (MAF) sensor P0107, P0108, P1128, P1129: Manifold absolute pressure (MAP) sensor P0133,P1172,P1157,P2195,P2238, P2252, P2AOO: Air fuel ratio (A/F) sensor (Sensor 1) P0134, P0135: Air fuel ratio (A/F) sensor (Sensor 1) heater P0137,P0138,P0139,P2270,P2271: Secondary HO2S (Sensor 2) P0141: Secondary HO2S (Sensor 2) heater P2646, P2647, P2648, P2649: VTEC system P0400,P0401,P0404,P0406, P2413: Exhaust gas recirculation (EGR) system P0443, P0496: EVAP canister purge valve 1. Check the fuel pressure. Is the fuel pressure OK? YES - Go to step 2. N0 - o If the pressure is too high, replace the fuel pressure regulator, then go to step 7. o If the pressure is too low, check the fuel pump, the fuel feed pipe and the fuel filter. If they are OK, replace the fuel pressure regulator, then go to step 7, 2. Check for vacuum leaks at these parts: o PCV valve o PCV hose o EVAP canister purge valve o Throttle body o Intake manifold o Brake booster o Brake booster hose o Air Intake duct Are the parts OK? YES - Go to step 3. NO - Repair or replace parts with leaks, then go to step 7. 3. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle. 4. Check for these conditions: o ECT SENSOR 1 above 176 F (80 degrees C) o Transmission in neutral o All electrical loads off 5. Monitor the ENG SPEED in the DATA LIST with the HDS, and hold the engine speed at 4,500 rpm . Once the engine speed is met, hold the accelerator pedal steady for more than 10 seconds . Did the engine speed vary more than 100 rpm from 4,500 rpm ? YES - Repeat step 5. NO - Go to step 6. 6. While holding the engine speed at 4,500 rpm , check the MAF SENSOR in the DATA LIST with the HDS. Is there about 14-20 gm/s ? YES - Check the engine valve clearances and adjust if necessary. If the valve clearances are OK, replace the injectors, then go to step 7. NO - Replace the MAF sensor/IAT sensor, then go to step 7. 7. Turn the ignition switch ON (II). 8. Reset the ECM with the HDS. 9. Do the ECM idle learn procedure. 10. Start the engine. Hold the engine speed at 3,000 rpm without load (in neutral) until the radiator fan comes on, then let it idle. 11. Test-drive under these conditions: o ECT SENSOR 1 above 176 degrees F (80 degrees C) o Transmission in neutral o All electrical loads off NOTE: DTC P0171 and/or P0172 may take up to 80 minutes of test driving to set. Using the HDS, monitor the long term fuel trim (LT FUEL TRIM) or the air fuel feed back average (AF FB AVE). If the long term fuel trim/air fuel feed back average stays within 0.80-1.25 , there is no problem at this time. 12. Check for Temporary DTCs or DTCs with the HDS. Are any Temporary DTCs or DTCs indicated? YES - If DTC P0171 or P0172 is indicated, go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting. NO - Troubleshooting is complete.

07-24-2007, 07:31 PM	#3 (permalink)
iknowmysh1t Senior Member Join Date: Mar 2007 Posts: 970 iTrader: 0 / 0%	bump for info?

07-25-2007, 01:20 AM	#4 (permalink)
taejinah Senior Member Join Date: Mar 2006 Posts: 399 iTrader: 0 / 0%	thank you soooooo much!

07-25-2007, 02:34 AM	#5 (permalink)
iknowmysh1t Senior Member Join Date: Mar 2007 Posts: 970 iTrader: 0 / 0%	no problem

07-25-2007, 09:09 PM	#6 (permalink)
taejinah Senior Member Join Date: Mar 2006 Posts: 399 iTrader: 0 / 0%	i dont think ive seen this posted anywhere before pertaining to the engine running rich scenario (especially for those with the injen cai). someone should sticky this somewhere? unless of course it's already somewhere.. and im just blind -_-

07-25-2007, 09:11 PM	#7 (permalink)
taejinah Senior Member Join Date: Mar 2006 Posts: 399 iTrader: 0 / 0%	after reading through that I decided it might be my intake manifold cuz i installed the hondata IMG a couple months ago. I've tried to re tighten all the bolts and reset the ecu... so far about a compiled hour or so of driving and cel hasn't come back yet... i also regrounded the fuel rail just in case that might be the problem. If cel comes back, I'll have to take it to the dealership to check all the fuel stuff hopefully not though.