Code 122 Even After Setting Tps

Discussion in '1994 - 1995 Specific Tech' started by from6to8, Jun 22, 2013.

  1. I Put on a new IAC from autozone few wks ago and was having a hung idle since put it on. Last nite got a CEL that stayed on for awhile last nite. Stopped at a gas station for bout 20 mins waiting on my boy to come home and when I left to go to his house, the engine light was gone. Got there and did a koeo and koer test. Only during the koeo test did I get a code 122 for TPS being too low. Drove home and no more engine light last nite. Today I read up on idle set procedures though I've done them before. Basically I backed off on the stop screw and got it set within the .10 and with IAC unplugged, I just went ahead and put 2 turns on the IAB screw since 2 is the max that you should go with that screw. When my son started the car up, it wanted t die so I turned the stop screw clockwise in small increments then revved up to see at what point it would stay running.

    I then backed off a little bit and got it set to where it would run without cutting off, at it's lowest idle. Thing is, the lowest it would idle without cutting off was about 900. I cut the car off and checked the TPS and it was .99 It had the 5 volt ref too. I drove her around for about 10-15 miles and it felt ok but still doesn't feel quite as it has when it has run its best and I'm talking throttle response. I stopped at one of my friends for about 5 mins and cut car off. When I started back up, the temp was at 210 and as I drove out his yard the CEL came on and the temp didn't decrease, it increase just a little so I cut the car off and waited about 30 mins or so. When I cut the car off it was around 180 degrees when I cut off at first stop so I'm wondering why when I started back up it said 210. After bout 30 mins drove her home and temps were around 180 and no CEL but when I did another koeo test, I got code 122 again and wondering why

    i'm going to just replace the T stat also just in case it's sticking but still trying to figure out this code and why
  2. What do you see as the voltage range from the idle position to WOT? Progression should be smooth with no dead spots.
  3. would I check that by revving the engine and watching the voltmeter and what range should it be?

    and if it isn't smooth?
  4. No, key on engine off . How did you check it earlier to arrive at the .99v? I didn't say what the range would be as I wanted you to test the range and report back so we could tell if you are testing correctly or if the TPS readings made sense.
  5. .97 was the reading with koeo and it was steady

    the .97 was the 2nd idle set procedure I did today and instead of going ahead and putting the IAB screw to 2 turns, I slowly turned it counter clockwise to get the idle at the lowest setting with IAC unplugged. I think the IAB screw is maybe a half a turn to one turn. But from everything I have read if I am within range the idle set shouldn't be a problem to where things have to be spot on as long as the car is idling.

    I think I might have a MAF issue and wish I had someone's to try out
  6. I guess we both should have been more clear lol . Someone from another forum said with engine off and key on I would rev the engine but not actually rev but as if the car was running , I would use the throttle blade to slide it
  7. just checked TPS from idle to WOT and it seemed smooth to me,increased as to how quickly I slid the blade. I did it slowly, then a lil faster. Max voltage at WOT was 4.68 though.

    There is a 5 volt ref when I probe the corresponding wire on it's own with the koeo test though
  8. 4.68v is okay for WOT. What you didn't want to see were times that the voltage didn't change or dropped off and then increase as the throttle was opening. The idle speed is a ECU commanded parameter and as such the ECU will do whatever it can to hold that spec. Without looking it up again it's about 650 rpm for a manual and 700 rpm for an auto.
    A key component to all this are the battery to engine and engine to chassis grounds as well as the ECU ground. Make certain they are good as it will affect every sensor.
  9. the thing is, I cannot get it to idle that low and it's a manual. With the idle set screw set to the .10 and turned 1 1/2 more turns, when I unplug the IAC and start up the car I have to rev it via the throttle blade and I have to turn the screw clockwise to get it to idle and stay running without cutting off. That position, the lowest it will idle without cutting off is 900. At that time, turning the IAB screw counterclockwise from it's tight position to opening it will raise the idle. So what do you say about the car not idling below 900 without cutting off?

    I still wish I had someone's MAF sensor that was calibrated for 24's to try. I'm wondering how good a shape mine is in? I recently cleaned it and have learned over the yrs how sensitive it is. I think next on the list to check are the grounds though everything appears to be fine. I want to take to a shop and let them check more in depth, as well as for vacuum leak that I checked for actually but they can probably do more in depth, and then trying another MAF. Also on a side note my exhaust while I'm at it but I checked header bolts and stuff recently too and will let them go more in depth though an exhaust leak from what I 've heard won't cause the issues I'm having