1998 Civic: code P0171: fuel pressure regulator?
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From: jim beam on 30 Jun 2010 19:00 On 06/30/2010 01:19 PM, Tegger wrote: > Kaz Kylheku<kkylheku(a)gmail.com> wrote in > news:20100701020701.901(a)gmail.com: > > >> >> There is also a test described for a stuck or leaking EVAP purge >> control valve. >> > > > > Asking for the THIRD time: > Are you sure you get a P0170 code in addition to the P0171? > > any "P0XXX" code is from the universal list, not a manufacturer specific list like "P1XXX". P0170 is "Fuel Trim Malfunction (Bank 1)" http://www.obd-codes.com/trouble_codes/ -- nomina rutrum rutrum
From: jim beam on 30 Jun 2010 19:01 On 06/30/2010 03:57 PM, Tegger wrote: > Kaz Kylheku<kkylheku(a)gmail.com> wrote in > news:20100630135833.210(a)gmail.com: > >> On 2010-06-30, Tegger<invalid(a)invalid.inv> wrote: >>> Asking for the THIRD time: >>> Are you sure you get a P0170 code in addition to the P0171? >> >> Yes; I think I can read the screen! Two different OBDII diagnostic >> programs show the same two codes. Both codes come back eventually >> after reset. >> > > > > Honda does not use P0170. it's not a honda-specific code because it's on the universal obdII list! http://www.obd-codes.com/trouble_codes/ > > Does your Check Engine light come on for two seconds when you first turn > the key to "II", and then go off and stay off, even after the engine > starts? > -- nomina rutrum rutrum
From: jim beam on 30 Jun 2010 19:09 On 06/29/2010 08:02 PM, Scott Dorsey wrote: > Kaz Kylheku<kkylheku(a)gmail.com> wrote: >> I don't currently have a fuel pressure gauge to be able to investigate >> pressures. >> >> But is there enough evidence that it may be purely a mechanical fuel pressure >> problem, (rather than, say, faulty O2 sensor readings?) >> >> Is there anything I can diagnose with OBDII before I shop for a fuel pressure >> gauge? > > When did you last change your fuel filter? highly unlikely this is an issue. filter congestion symptom is starvation when you're on a hill, fully loaded, and with a strong head wind. not before. honda filters are high capacity and are typically good for hundreds of thousands of miles. > >> I don't think I have an exhaust manifold leak, either. I had one previously >> which was so bad, you could smell it from the ventillation; and there was no >> such code coming up. The driveability was way worse than now. I recently, >> about two months ago, changed the top O2 sensor (for a working used one, which >> came from my old broken manifold), at which time I inspected the exhaust for >> cracks; didn't see any at that time. > > I'd still get out a propane torch and make a basic test for leaks. > --scott -- nomina rutrum rutrum
From: Tegger on 30 Jun 2010 19:09 Tegger <invalid(a)invalid.inv> wrote in news:Xns9DA7C0BCF4507tegger@ 208.90.168.18: > Kaz Kylheku <kkylheku(a)gmail.com> wrote in > news:20100630135833.210(a)gmail.com: > >> On 2010-06-30, Tegger <invalid(a)invalid.inv> wrote: >>> Asking for the THIRD time: >>> Are you sure you get a P0170 code in addition to the P0171? >> >> Yes; I think I can read the screen! Two different OBDII diagnostic >> programs show the same two codes. Both codes come back eventually >> after reset. >> > > > > Honda does not use P0170. > > Does your Check Engine light come on for two seconds when you first turn > the key to "II", and then go off and stay off, even after the engine > starts? > Just to clarify why I've asked this: spurious codes usually mean the ECM is going bad. I suggest you pull the ECM, remove its cover, and check for moisture or corrosion inside the ECM case. Your ECM should be behind the passenger-side kick panel, under the dashboard, just ahead of the door. -- Tegger
From: jim beam on 30 Jun 2010 19:11
On 06/30/2010 12:41 PM, Kaz Kylheku wrote: > On 2010-06-30, Kaz Kylheku<kkylheku(a)gmail.com> wrote: >> I'm going to do the O2 sensor test described in the service >> manual. (Hold engine at 3000 RPM until fan comes on, then >> scan the output of #1 O2 sensor, which should be 0.3 to 0.6V. >> If it's out of that range, it should be replaced.) > > I did some driving while monitoring the O2 sensors and fuel trim. > Some interesting findings. > > The #2 O2 sensor basically has binary behavior it either reads about 0.9xx > volts most of the time except during DFC0 (driving in gear with foot off > throttle), when it reads a low voltage of 0.0xx at 0% fuel trim. > > The #1 fuel trim and O2 reading can be described as having demonstrated two > personalities. > > During the first fifteen minutes of the run, fuel trim was usually at 46.9%, > when accelerating, driving steadily at around 50-60 km/h, and even when idling > in neutral at stops. The O2 sensor was reading about 0.485 to 0.505 volts all > the time, except when coasting to a stop (DFCO) it would drop down into the > 0.2xx range. > > Then while I was cruising on a stretch of highway at 90 km/h, the fuel trim > value adjusted down to 35%. The #1 O2 sensor value dropped, to about 0.465. > Next, after I coasted to stop at a red light, the fuel trim cut to 5.5%, and > the O2 reading was only 0.2xx. Big difference from previous stops, when it was > 0.4xx and trim at 46%. > > After that, there was a bit of street driving at 50-60 km/h before arriving at > my destination. Now, the fuel trim did not go above 35%, and the oxygen sensor > stayed in the 0.3xx range. At each stop, the trim dropped to 5.5% and > the sensor to 0.2xx. > > My interpretation is that this may be a bad O2 sensor, since peak value I > observed was 0.505V, even at high fuel trim. It never indicates a rich > mixture. Come on, the car eats a lot of gas, and its exhaust stinks of > unburned fuel. You would think the O2 would indicate rich at some point? > > The observed change in behavior could be that the ECU realizes that the O2 > lean indication is garbage, and cuts back the rich fuel trim. > > Hmm; looks a lot like the repair bucks should be spent in the direction of a > new O2 sensor. Will check for that possible exhaust manifold leak, though. those trim percentages seem crazy high. normally, "trim" means deviation in the average from stoichiometric, and that should be just a few percentage points. i'd two two things at this point: 1. because of the age of the vehicle, i'd go to http://oxygensensors.com/ and get a new oem sensor - ngk or denso, not bosch on a honda. 2. i'd double check on the potential vacuum leak scenario. as scott dorsey says, use a propane source to diagnose. -- nomina rutrum rutrum |