Running Rich, Code 31

+ Reply to Thread
Results 1 to 2 of 2

Thread: Running Rich, Code 31

  1. #1
    Great White mysupratoy94's Avatar
    Join Date
    Nov 2003
    Duarte, CA

    Running Rich, Code 31

    Hey guys, so a while back my 93.5 NA was stalling after a few seconds. We determined it was an ECU issue because I was not getting my CEL with key in ignition and my scanner would not communicate with my ECU. I had some leaking resistors so I had the ECU repaired.

    I went ahead and installed it and now the car stays on, I get my CEL and so on but it was idling very low and got a CEL 31 code.

    While I was checking for vacuum leaks I checked my spark plug wires and noticed some arching. Wires were bad. I went ahead and replaced plugs, cap and rotor, wires, valve cover gaskets, PCV valve, EGR and Throttle Body gaskets and cleaned both EGR and Throttle body. Also cleaned the IAC valve.

    Now I can actually drive the car without it stalling but its running super rich and I'm still getting code31. I went ahead and removed the air flow sensor since that's what code 31 is for and it looked fine. I have been cleaning that sensor since ive owned the car which has been almost 15 years or so with no problems. I just now notice everyone says we shouldn't be cleaning them. Anyhow I don't visually see anything wrong with it.

    One thing that makes me feel like its a bad sensor is because if I disconnect it while the engine is running, nothing changes. Is that normal?

    Like I said, I can now drive the car and it has power but while driving and coming to a stop it hesitates as if its going to stall but doesn't.

    Besides replacing the air flow sensor, is there anything else I can try? I'm so close to being able to drive my car, any help will be greatly appreciated.

  2. Remove Advertisements

  3. #2
    Great White mysupratoy94's Avatar
    Join Date
    Nov 2003
    Duarte, CA
    Quick update, I received a new MAF sensor from eBay. I installed it and the car won’t start with it installed. I removed it, installed my original one and the car started right up. It still up and down from like 400 rpm to 900. If I accelerate it does so smoothly. Just on idle it fluctuates. Again, if I remove the connection from the sensor nothing happens.

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

List your Car(s)

Where you live

Please select your insurance company (Optional)

Your Supra's Vehichle Identification Number (Not visible to the public)


Similar Threads

  1. Running Rich, Real Rich.
    By redsphill in forum MKIV Technical
    Replies: 1
    Last Post: 09-14-2009, 06:45 PM
  2. Help! Code 25 & 26 - Running lean and rich?! WTF?
    By Astig Boy in forum MKIV Technical
    Replies: 13
    Last Post: 08-22-2007, 10:43 PM
  3. Rich rich rich
    By hornick in forum MKIV Technical
    Replies: 10
    Last Post: 05-18-2007, 09:09 AM
  4. Code P0172 (running too rich; I have an HKS AFR)
    By michaelvanle in forum MKIV (1993-1998)
    Replies: 2
    Last Post: 12-22-2004, 04:19 PM
  5. Code 51 and Code 31
    By Trent in forum MKIII (1986.5-1992)
    Replies: 9
    Last Post: 02-22-2003, 11:17 PM

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts