Car stalls when in neutral

Discussion in 'Modifications & DIY how-to' started by Cool_____, Aug 27, 2008.

  1. Cool_____

    Cool_____ Banned

    I've searched and ran across a few things that didn't work at all.

    My issue is the car will not catch it's idle and die if I press in the clutch and let the rpms fall when I coast to a light or something. I found a thread that said to clean the IACV and I did. The IACV was sticking a little and it doesn't now but the problem is still there. I also cleaned my MAF by sticking it in a bad with rubbing alcohol like I have in the past.

    I have no intake/vaccum leaks and the car runs fine WOT and cruising with one exception. If I come up on a car and have to ease off the throttle and cruise at full vac (boost gauge reads 20ish vaccum) the car is studdering and jerk very bad.

    I've also replaced the front o2 and that didn't help at all. No CEL's at all other than the rear o2 heater circuit that popped up last night (p0032). Also my EWG is stuck open but that's another issue and this was going on prior to the EWG being stuck open.

    Can anyone think of ANYTHING else? I'm swapping with my buddy to see if the MAF itself may be bad but is there anything else?
     
  2. Kokopelli

    Kokopelli Active Member

    And the results of the compression test are?
     
  3. nsvwrx

    nsvwrx Active Member

    he said 160 across the board
     
  4. Cool_____

    Cool_____ Banned

    Yep 160 across the board. Rick is having similar issues guys.
     
  5. clemsonscooby

    clemsonscooby Active Member

    Does it lurch like its still slightly in gear?
     
  6. Cool_____

    Cool_____ Banned

    Yes! It's horrible! Someone on Nasioc said it could be my TGV sensors? Could that be the case?
     
  7. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    Wierd... when did it start doing this?
     
  8. Cool_____

    Cool_____ Banned

    Well it cut off like twice a week after you tuned it. I thought I lugged the motor too low so I ignored it. Then it started getting worse and now it does it every time. It's NOT the tune though....just as a test I tried Scotts old map and it still did it.

    It's AGGRAVATING and dangerous.
     
  9. Kokopelli

    Kokopelli Active Member

    Rick thinks his maybe related to the dccd wiring. Have you checked yours?

    I would log the tps sensor and see if it is acting wierd because of the controller.
     
  10. WRXCoupe

    WRXCoupe Active Member

    Bump tps sensor. possibly MAF? Any codes?
     
  11. Cool_____

    Cool_____ Banned

    No codes other than the dead rear o2. Swapped MAFS with a known good one. Not a change. I also checked the wiring at the ECU. It's fine. Maybe I should kill the power to the DCCD controller?
     
  12. wrxin8or

    wrxin8or Mullitt Staff Member

    Reset the ECU after you swap MAFs (You probably did, but just to make sure)
     
  13. WRXCoupe

    WRXCoupe Active Member

    If the tps is easy to get to swap one out with somebody and try that, other than that maybe it's a fuel pressure issue, simply because idle at neutral is a couple of rpms down and it sound like fuels not getting there at lower idle. Used to have these problems with Mustangs allot, granted I am an amatuer:)
     
  14. Cool_____

    Cool_____ Banned

    Actually I didn't bc I was in the parking lot at work. Following my Suby buddy home for further investigation. Keep the suggestions going though.
     
  15. techlord

    techlord Active Member

    sounds like yours is worse than mine as my car has not cut off in quite sometime. I took it on a 2 hr jouney the other day and it seems like it does it on decel right as I am about to apply pressure to the gas pedal. I did however notice that it got progressively worse as the car heated up, I still think I hear a preturbo exhaust leak. I will check the dccd when I get home...the fam is out for the night so I will finally have some time to play.
     
  16. techlord

    techlord Active Member

    hey delette just curious did you have any C16 since your last tune? If so that is the only thing we MAY have in common since our tune.
     
  17. Cool_____

    Cool_____ Banned

    Nope....no C16.
     
  18. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    Check the canuter valve. Some times the stick causing an idle issue
     
  19. Cool_____

    Cool_____ Banned

    What in world is a canuter valve?
     
    Last edited: Aug 27, 2008
  20. wagunz_pwn

    wagunz_pwn Active Member

    Last edited: Aug 27, 2008
  21. Cool_____

    Cool_____ Banned

    Oh jeez now you got me good there. I was like What in the Heck is that? LOL

    Seriously now guys I have a tune appointment Wednesday....I need this fixed before then.
     
  22. wagunz_pwn

    wagunz_pwn Active Member

    :slap:

    Sorry, had to. Good luck with everything...damn, I was hoping to hear you got everything installed and was ready to install the OAT. :keke:
     
  23. Cool_____

    Cool_____ Banned

    I don't think my IACV is borked. I swapped with Daniel and it made no difference. Also swapped MAfs and no difference. I'm sick of this.....what else.....paging WJM....
     
  24. Cool_____

    Cool_____ Banned

    What else plays a role in the idle?
     
  25. josh booth

    josh booth Active Member

    I am not sure but my car started doing this after I got my trans rebuilt and had a light weight flywheel put in. I was thinking this was my problem but after reading this maby I was wrong . Let me know if you find what the problem is.
     
  26. Cool_____

    Cool_____ Banned

    Someone has mentioned TGV sensor but I don't think it has ANYTHING to do with catching the decel idle does it? It'll fall to zero, catch and stumble slightly and the idle will bounce very little from like 0-500 and sometimes it catches and sometimes it dies. If I hit the brakes while this idle 'hunt' is going on it'll die. Could the battery have 'ANYTHING' to do with this because of voltage? The turbo timer stays at 13.9 Voltage for the most part.
     
  27. WJM

    WJM Banned

    TGV has nothing to do with it. TGV's are only closed upon cold start. As soon as the vehicle has motion or the throttle is moved, they open. Warm and hot start they cycle open-closed-open as a system check.

    I've had several cars come in with this idle issue and each solution was not similar to the other.

    Did you check for manifold vacuum leaks? Did you check the IC piping for leaks? Did you check the MAF to turbo compressor housing for leaks?
     
  28. Cool_____

    Cool_____ Banned

    I did a boost leak test and heard nothing. However I'm wondering if the BOV isn't seal under vaccum? Think that may be the issue? I tightened it but that didn't do anything. I wish I could figure out how to use the stock BPV.
     
  29. Cool_____

    Cool_____ Banned

    We tested up to 12 psi. Do we need to go higher? How do you check the manifold for vacuum leaks? Spray carb cleaner while the car is idling? The IC piping is definately not leaking. Maf to turbo compressor is silent under 12 psi.
     
  30. WJM

    WJM Banned

    Ok.

    Is the engine under increased rotational friction? Meaning does it sound like its harder for the starter to turn over?

    Its starting to sound like a sensor issue to me.

    Unplug the MAF and start the car. Obviously, the CEL will come on for MAF and IAT. But the important thing is: Does the car run well now?
     
  31. Cool_____

    Cool_____ Banned

    Will the car idles just fine. Starts fine and idles just fine and dandy. It only dies when the rpms are higher than 2000 ie cruising and you put it in neutral and let the rpms fall. It won't 'catch' its idle everytime.

    I had Daniel test his car and he said he noticed his car catches (or should say the rpm drop speed slows down) at 1500 rpm then 1000 rpm and then it's set idle. Mine not doing that....it just falls straight to set idle or less. Once it establishes the set idle it idles perfect. If the car stalls off then I crank it right back up and it's all fine and dandy until I pop the car into neutral again and let the rpms drop.

    Does that make sense? I can make a vid if it helps.
     
  32. Cool_____

    Cool_____ Banned

    Just got off the phone with SS and we think I may have an electrical issue with a battery going out or a grounding issue. I'm getting that checked at lunch time.
     
  33. Cool_____

    Cool_____ Banned

    Battery and alternator are in perfect working order. Back to the drawing board.

    WJM you think TPS may be it?
     
  34. WJM

    WJM Banned

    Sounds like the ECU is not recognizing that the engine is returning to an idle state...aka the 'idle switch' which is now a parameter built into the ECU and not a separate switch.

    You could have a defective TPS. Swap that.
     
  35. Cool_____

    Cool_____ Banned

    Will do. Is there a gasket I need to worry about or is it an o-ring deal like the MAF?

    I'm also gonna swap coil packs even though they are running fine. I have had 1 of them go bad in the past.
     
  36. WRXCoupe

    WRXCoupe Active Member

    "You could have a defective TPS. Swap that."

    Yup that's what I thought
     
  37. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    What BOV is on your car?
     
  38. Cool_____

    Cool_____ Banned

    The APS 50/50 recirc one. Siegel told me to buy it.
     
  39. Cool_____

    Cool_____ Banned

    After EXTENSIVE searching in the worst search database known as Nasioc I came across a thread where a guy was having the exact same symptoms I did. He did everything I did and then he remembered when he cleaned his IAC that you could tilt the IAC motor some. He adjusted it and it fixed his problem. However I think the manual says not to fix idle issues this way.

    WJM can you shed light on this or anything? Worth a shot? I'm getting retuned so if it affects that but can be fix with a retune that's fine by me.
     
  40. WJM

    WJM Banned

    Swap TPS first.

    No gaskets/orings or anything fancy. You can swap the TPS with the TB on the manifold, but you'll need some JDM moves to get one of the phillips screws out....so you could just take the TB off and do it that way.
     
  41. Cool_____

    Cool_____ Banned

    10-4! Nice to have someone so willing to help me ;)
     
  42. Doug@DBW Motorsports

    Doug@DBW Motorsports Active Member

    Check to make sure the aps valve is closing all the way, I have seen some that get stuck in the open position. Doing a pressure test will not show this as the pressure usually closes them. Its not untill you drive the car around under normal conditions IE: vaccum that the valve becomes stuck. If it does get stuck open then the car will most likely stall.

    Just another thought.
     
  43. Cool_____

    Cool_____ Banned

    That is what I'm going to check. I am going to take it off and plug the holes and drive the car without a bov but stay OUT of boost.
     
  44. WJM

    WJM Banned

    Doug speaks truth. I've seen the APS stick open. The TXS and others stick as well.
     
  45. Cool_____

    Cool_____ Banned

    I took the APS off but left it hooked to the recirc hose. Plugged the other hose and it still did it. However that wasn't a good test because I had no BOV.

    Doug can you 'see' this sticking on the dyno? WOT I should be fine right? Tuning should be fine and I'll just need to get the BOV replace right? Maybe you guys have one lying around the shop that I can swap real quick to test that theory.


    Meanwhile I adjusted the IACV so now it won't die. It was getting dangerous dieing at turns and stop lights. Tomorrow I am spending a lot of time pressure testing.
     
  46. WJM

    WJM Banned

    Yes you can see this on the dyno.
     
  47. techlord

    techlord Active Member

    any news here? Just picked up another $&*^ so I have been too busy to mess with mine.
     
  48. Cool_____

    Cool_____ Banned

    No but it's not nearly as bad since I adjusted the IACV. However it idles high for a few seconds before dropping to desenated idle but I can deal with that. LOL
     
  49. Cool_____

    Cool_____ Banned

    Maybe Scott will see something when I am on the dyno Wednesday.
     
  50. techlord

    techlord Active Member

    did the surging stop? Mine does not die or has not but maybe once in the past 2 months but the surging is getting annoying. Especially since I will be driving her more in the upcoming months.
     

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