system too rich
 

So the other day i was sitting in rush hour traffic on the freeway, when all of a sudden my check engine light comes on. When i got home i took out my MAF and clean it started and the light came of, but the code stored in the ecu say the p0172 system is to rich(bank 1). My car studder when i start moving in first gear like it has no power. I'm stumped on the problem.

Sounds like an O2 sensor fault code to me... check your front O2 sensor out. The rear one could have set this code.

At the risk of being a post whore, I think I should add a little more detail. If something is wrong with the front O2 sensor (low voltage), it could tell the ECU to run rich. The rear O2 sensor would set the fault because it would recognize the rich condition. In an OBD2 car, the front O2 sensor does the work (regulates between rich and lean) and the rear O2 makes sure that the catalysts and front O2 are doing their job.

Hi Juddz, I took ur advise and i replaced my front O2, and the car still studders. What other possibilities could it be??

check the TSB's...possible MAF issue..Mazda extended the warranty up to 75,000 miles on 1.6L's

Sorry my idea didn't fix the problem...

Macdaddyslomo, where can jster28 go to review Technical Service Bulletins? Aren't these something that only the dealers have access to?

Roddimus, do you have any thoughts on this? C'mon, man - we need your ASE-certified expert opinion!

I have another question for you, jster28 - are there any other P-codes that you are getting? If so, what are they? And, after you replaced the O2 sensor, did you disconnect the battery to allow the ECU to reset itself?

You can go to the protege faq to get the tsb's
http://web2.airmail.net/theman/protegefaq/tsb/

macdaddy, the maf warranty doesnt apply to california emissions car. I been to the dealer and they said that there isnt one for my car. It shouldn't be the maf, cuz i replaced it a few months ago with a used one from a junk yard. I checked the tsb cant seem too find anything, but thanks though. I might just end up taking it to a shop :(, more money, i rather not spend.

Alright, jster28 -
I have one more suggestion for you before you take it in to the shop. Your problem could be related to a stuck fuel injector. Why don't you pull your spark plugs, and take a look at them? Keep them in order, so you know which cylinder each one came from. And, check to see if one looks different from the others (black deposit, raw fuel, etc). If one looks drastically different from the others, it could be an indicator of an injector issue.

If you can confirm if there are any other fault codes, it would help me to diagnose your problem further. I half expect to see a misfire code (P0301, P0302, P0303, or P0304).

Please try the above if you get a chance, and let me know what you come up with. Lets see if we can take care of this issue without breaking your bank account.

Is the CEL code still active in the system? If so please give me the code number.

Rough idle, vibration, and poor running can be NUMEROUS things. On something so vague I tend to not give specific advice.

I understand the first code was a system rich code. The code could be thrown by the o2 sensor but only after it realizes a problem somewhere else in the system. For example. Your primary o2 sensor says too rich. Well, your IAT sensor determines ambiant air temps and signals the ecu to adjust the amount of fuel need to warm the car up. If the sensor is faulting and telling the ecu it's -120* outside the Ecu is going to DUMP fuel into the motor. The ecu is doing this and thinking it's doing everything right but your o2 sensor is seeing tons of unburnt fuel and throwing a "rich" code.

Macdaddy is also right. It could be another MAF problem. This is another piece that is used by the ECU to determine the correct A/F ratios.

make sense? I wish I could help, but Id want to see the car in front of me before telling you to replace parts.

p.s. juddz is right, check the plugs and let us know what you see....pics are MOST helpful

Is the CEL code still active in the system? If so please give me the code number.

Rough idle, vibration, and poor running can be NUMEROUS things. On something so vague I tend to not give specific advice.

I understand the first code was a system rich code. The code could be thrown by the o2 sensor but only after it realizes a problem somewhere else in the system. For example. Your primary o2 sensor says too rich. Well, your IAT sensor determines ambiant air temps and signals the ecu to adjust the amount of fuel need to warm the car up. If the sensor is faulting and telling the ecu it's -120* outside the Ecu is going to DUMP fuel into the motor. The ecu is doing this and thinking it's doing everything right but your o2 sensor is seeing tons of unburnt fuel and throwing a "rich" code.

Macdaddy is also right. It could be another MAF problem. This is another piece that is used by the ECU to determine the correct A/F ratios.

make sense? I wish I could help, but Id want to see the car in front of me before telling you to replace parts.

p.s. juddz is right, check the plugs and let us know what you see....pics are MOST helpful

Yes, send us pictures!

Well guys, here is an update on my car. the problem has been fixed :D . I check the plugs this morning and they were fine. I found out that a distant relative of mine owned shop, so i took the car their. First we ran the codes (P0172). then we verified that DTC P0172 was present in FREEZE FRAME PID data. then he monitored the FH02s, checked the fuel line pressure. Make a long story short it was my MAF, it was really dirty. I only cleaned the little bulb thingy, but he spray some cleaner in the barral of the sensor and a lot of crap came out (why didnt i think of that). problem fixed. Thanks for all the replies and help everyone provided. Lucky me i didnt have to go break my piggy bank :D . All my he wanted in payment was a six pack of beer.
http://img.photobucket.com/albums/v233/jster28/maf.jpg

nothing like having a drunk mechanic!! I ended up with some WEIRD runnig cars using that payment method!!

told ya !!! that MAF is super sensitive..I might have to clean mine what kind of cleaner did he use???