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-   -   P0172 system too rich bank 1 question (http://mustangforums.com/forum/4-6l-1996-2004-modular-mustang/697417-p0172-system-too-rich-bank-1-question.html)

cowman79 06-27-2013 05:00 PM

P0172 system too rich bank 1 question
 
On my 96 4.6 gt I have gotten a P0172 a couple of times so I started doing some investigating and found that when the engine was running the bank 1 sensor 1 was running around 1% and the bank 1 sensor 2 was running around -100%. I was wondering if this is a downstream o2 sensor problem or something else. I have attached a screen shot of my torque app with the sensor info.



http://i1146.photobucket.com/albums/...ps84499d35.png


Thanks for the help.

cariacou 06-27-2013 05:02 PM

o2 rear sensor

school boy 06-27-2013 05:56 PM

P0172 OBD-II Trouble Code

Technical Description

System Too Rich (Bank 1)

What does that mean?

Basically this means that an oxygen sensor in bank 1 detected a rich condition (too little oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.

Note: This DTC is very similar to P0175, and in fact your vehicle may show both codes at the same time.

Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a misfire.

Causes

A code P0172 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 can 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.
•There could be a fuel pressure or delivery problem

Possible Solutions

Possible solutions include:
•Inspect all vacuum and PCV hoses, replace if necessary
•Cleanthe MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
•Inspect fuel lines for cracks, leaks, or pinches
•Check the fuel pressure at the fuel rail
•Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
•Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)

cowman79 06-27-2013 07:57 PM

I have seen the same troubleshooting guide before. I have cleaned my mass air sensor and the light came on about a week later. That is why I got the Bluetooth code reader to try and get some better data for troubleshooting. I am now leaning towards the bank one sensor 2 oxygen sensor because of the way it is reading on the live data screen shot.

school boy 06-27-2013 09:35 PM

Well the reason I posted that is to do the small cheap things first. Im leaning towards a o2 sensor myself but I always like to check the small things first.

art02gt 06-27-2013 10:44 PM

rear o2 sensors only monitor cat efficiency and have nothing to do with the engine running rich or lean. you have a rich condition which means you either have too much fuel or not enough air. I wouldn't throw parts at it yet, the first thing I would do is check for vacuum leaks (pcv hoses, intake gaskets etc.).

cowman79 06-28-2013 08:18 AM

Quote:

Originally Posted by art02gt (Post 8239273)
rear o2 sensors only monitor cat efficiency and have nothing to do with the engine running rich or lean. you have a rich condition which means you either have too much fuel or not enough air. I wouldn't throw parts at it yet, the first thing I would do is check for vacuum leaks (pcv hoses, intake gaskets etc.).

If I have a rich condition then why isnt the bank one sensor 1 showing a high reading. If both sensors are in the same gas stream then wouldnt they both have similiar readings.

art02gt 06-28-2013 11:33 AM

Quote:

Originally Posted by cowman79 (Post 8239368)
If I have a rich condition then why isnt the bank one sensor 1 showing a high reading. If both sensors are in the same gas stream then wouldnt they both have similiar readings.

what you posted are fuel trim readings. o2 readings are in volts.

cowman79 06-28-2013 12:42 PM

Quote:

Originally Posted by art02gt (Post 8239430)
what you posted are fuel trim readings. o2 readings are in volts.

Wouldn't the fuel trim be derived from the o2 rreading. If all of the other fuel trims are around 0 then wouldn't the problem have something to do with that banks sensor 2.

art02gt 06-28-2013 04:18 PM

Quote:

Originally Posted by cowman79 (Post 8239475)
Wouldn't the fuel trim be derived from the o2 rreading. If all of the other fuel trims are around 0 then wouldn't the problem have something to do with that banks sensor 2.

fuel trims are calculated and adjusted from the upstream o2 sensor, not the rear.

cowman79 06-29-2013 03:45 PM

Quote:

Originally Posted by art02gt (Post 8239563)
fuel trims are calculated and adjusted from the upstream o2 sensor, not the rear.


Since it appears that I have a fuel air problem I guess I will check a little closer for vacuum leaks. The previous owner installed an aftermarket BBK throttle body and a BBK CAI. He didn't install the BBK mass air flow sensor it appears that he reused the factory one. I have already checked the mass air to make sure that it is clean and there was no debris or oil on the wires.


This is a picture of the CAI and throttle body

http://i1146.photobucket.com/albums/...ps63f93dd8.jpg

art02gt 06-30-2013 12:32 PM

Quote:

Originally Posted by cowman79 (Post 8240018)
Since it appears that I have a fuel air problem I guess I will check a little closer for vacuum leaks. The previous owner installed an aftermarket BBK throttle body and a BBK CAI. He didn't install the BBK mass air flow sensor it appears that he reused the factory one. I have already checked the mass air to make sure that it is clean and there was no debris or oil on the wires.


This is a picture of the CAI and throttle body

http://i1146.photobucket.com/albums/...ps63f93dd8.jpg

a mass air fault would cause both banks to run rich/lean. you have a bank specific problem. since you're running rich it could be a leaky injector on bank 1 or maybe something clogged that won't let proper airflow in to a cylinder in bank one. it is very rare, but maybe your upstream o2 could be at fault. or even rarer, it could be your pcm. I worked on an f-150 with your problem. I took the injectors out and turned the key on (engine off) and injector #2 would slowly start to form a little drop of fuel (leaking), BUT as soon as I would electronically disconnect the injector the leaking would stop. so it was a pcm problem. if it would have continued to leak disconnected, then it would have been a bad injector.

cowman79 06-30-2013 05:18 PM

I've never worked on injectors like this before can you lift them all off while connected to the fuel rail and perform the test you are talking about. Also how do you test these injectors. Or is there a certain lifespan for these Injectors. The car has about 150k on it.

art02gt 06-30-2013 07:42 PM

Quote:

Originally Posted by cowman79 (Post 8240455)
I've never worked on injectors like this before can you lift them all off while connected to the fuel rail and perform the test you are talking about. Also how do you test these injectors. Or is there a certain lifespan for these Injectors. The car has about 150k on it.

you can remove the fuel rail with the injectors still on it. just make sure they are still seated in to the rail when you turn the key on or the fuel pressure will pop them out of the rail. and remember you are only turning the key on DO NOT crank the engine. See if you can actually get some proper o2 readings first, I usually leave these kind of tests for last.

cowman79 06-30-2013 07:45 PM

I will check the o2 volts tomorrow. I though they were running around the same as bank 2. maybe .7 volts

cowman79 06-30-2013 07:47 PM

When I was watching the switching on the graph it appeared the there was a little bobble at the top of the sine wave on bank 1. The bobble wasn't there all of the time but occasionally I saw it. Not sure what caused that.


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