Author Topic: bad idle  (Read 20439 times)

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #15 on: July 15, 2008, 12:47:08 PM »
Another update.  Replaced the engine temp sensor with no positive... or negative effects.  Still hesitates/dies upon initial startup.  After 30 seconds to a minute it is perfectly fine and runs great.  I would feel bad about spending the $180 in parts that this has cost so far, but the car runs way better than it did before after warm up... so even though I haven't found the problem, the car is way more fun to drive.  Going to take it in to a local shop and have them do a smoke test on it to see if there are ANY vacuum leaks from the gaskets.  Need to try the TPS too.  Also going to do a COP conversion when i get some more $$$.  Hopefully one of these 2 will fix the situation as it is kind of annoying having to wait for the car to stop hesitating.

1. ICV (replaced)
2. Vacuum Leaks (did TB heater delete and replaced hoses)
3. o2 Sensor (replaced)
4. Plugs & Wires (replaced as part of maintenance)
5. Fuel Injectors (mustang 19#)
6. Exhaust Header Gasket (had a leak)
7. AFM (replaced)
8. Engine Temp Sensor (replaced)


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

jrobie79

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 350
    • View Profile
bad idle
« Reply #16 on: July 15, 2008, 11:59:20 PM »
swapped in my sisters AFM, same thing, although i didnt really drive it for any extended amount of time, so this weekend i might take it out and swap again for a while this time. lemme know your progress

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #17 on: July 16, 2008, 12:45:58 PM »
Quote from: jrobie79;53350
swapped in my sisters AFM, same thing, although i didnt really drive it for any extended amount of time, so this weekend i might take it out and swap again for a while this time. lemme know your progress


I'll keep you updated.  Remember to disconnect the battery to clear the codes.  10 minutes is fine.  My car runs great for awhile after resetting the codes, but always comes back within an hour or two.  Out of curiosity, do you have an exhaust leak at all before the o2 sensor?


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #18 on: July 28, 2008, 10:24:51 AM »
Any updates?  I tried swapping my throttle position sensor... no luck.  Now I am going to take it to a local shop that I trust and have them do a smoke test to look for any leaks that might be present.  We'll track this down yet!


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

EN318isPDX

  • Hero Member
  • *****
  • Thank You
  • -Receive: 0
  • Posts: 650
    • View Profile
    • http://www.cardomain.com/id/ItotheAtotheN
bad idle
« Reply #19 on: July 28, 2008, 10:37:13 AM »
Quote from: AcSchnitzer318is;53899
Any updates?  I tried swapping my throttle position sensor... no luck.  Now I am going to take it to a local shop that I trust and have them do a smoke test to look for any leaks that might be present.  We'll track this down yet!

Have you checked your fuel pressure? my m42 had starting out and idle issues because of the fuel pump. Filters are wicked cheap always replace them. I had to take my car down to the dealer to get my running issue figured out.. Local BMW shops couldn't figure it out for some reason.

My list of parts.

Intake Gaskets
O2
OEM Injectors
Fuel Filter
Intake L Boot
All Vacuum Lines
New OEM ICV
OEM TPS

Even with all that my car still ran poorly.

Fuel pump is what gave me all my horsepower back.
« Last Edit: July 28, 2008, 10:39:38 AM by EN318isPDX »
WTB 97+ M3 Front Strut Assembly and 97+ M3 Control Arms (caster is important)
WTB Driver side Diamondschwartz fender PST

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #20 on: July 28, 2008, 10:46:52 AM »
Quote from: EN318isPDX;53903
Have you checked your fuel pressure? my m42 had starting out and idle issues because of the fuel pump. Filters are wicked cheap always replace them. I had to take my car down to the dealer to get my running issue figured out.. Local BMW shops couldn't figure it out for some reason.

My list of parts.

Intake Gaskets
O2
OEM Injectors
Fuel Filter
Intake L Boot
All Vacuum Lines
New OEM ICV
OEM TPS

Even with all that my car still ran poorly.

Fuel pump is what gave me all my horsepower back.


lol I've done everything on your list plus some but not the intake gaskets.  Well, the car runs great after initial 1 or 2 minutes of stumbling.  I put down 122rwhp after the stumbling so I don't think I am losing any performance.  Would think if it were a fuel issue, it would stay the entire time the car was on?  Plus it gets better if I reset the computer.  But always comes back within an hour.


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

EN318isPDX

  • Hero Member
  • *****
  • Thank You
  • -Receive: 0
  • Posts: 650
    • View Profile
    • http://www.cardomain.com/id/ItotheAtotheN
bad idle
« Reply #21 on: July 28, 2008, 10:53:16 AM »
I thought the same thing. I thought my car wouldn't run with a bad fuel pump. But it turns out that carbon had eaten past the intake filter and had slightly clogged up my pump. So part of the time i had 80% power but cold i had 30% of my power. If i filled it up i would put down a little more power. It was way more intermittent than i could have thought which is what made me think sensors like crank or cam.
WTB 97+ M3 Front Strut Assembly and 97+ M3 Control Arms (caster is important)
WTB Driver side Diamondschwartz fender PST

big red

  • Newbie
  • *
  • Thank You
  • -Receive: 0
  • Posts: 24
    • View Profile
bad idle
« Reply #22 on: July 31, 2008, 04:25:11 PM »
Here,s wishing you luck. I'm sure I'm not the only one hopeing you find the issue. Realy apreaciate the thread, I'm sure I'll refer to it alot when I get time ( and $$$ ) to do mine. Keep your heads up! :)

jrobie79

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 350
    • View Profile
bad idle
« Reply #23 on: July 31, 2008, 05:57:48 PM »
no dice, my fuel pump and filter have both been replaced within the last year or year and a half, i did change my valve cover gasket, so maybe thats the problem, when i tackle the timing chain ill see if the problem is back when im done. any one get any luck?

EN318isPDX

  • Hero Member
  • *****
  • Thank You
  • -Receive: 0
  • Posts: 650
    • View Profile
    • http://www.cardomain.com/id/ItotheAtotheN
bad idle
« Reply #24 on: July 31, 2008, 06:01:22 PM »
Quote from: jrobie79;54119
no dice, my fuel pump and filter have both been replaced within the last year or year and a half, i did change my valve cover gasket, so maybe thats the problem, when i tackle the timing chain ill see if the problem is back when im done. any one get any luck?


If i was you i would look for intake leaks by spraying brake cleaner in and around your intake..
WTB 97+ M3 Front Strut Assembly and 97+ M3 Control Arms (caster is important)
WTB Driver side Diamondschwartz fender PST

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #25 on: July 31, 2008, 11:25:24 PM »
Well another swing and a miss guys.  Replaced my TPS with no luck.  Only thing left for me to change are the intake gaskets... but I sprayed a bunch of carb cleaner around the intakes... got no change in results.  I think I am going to take it to my local indy to have them do a smoke test and find any and ALL leaks the car has.  Will keep the updates coming.

1. ICV (replaced)
2. Vacuum Leaks (did TB heater delete and replaced hoses)
3. o2 Sensor (replaced)
4. Plugs & Wires (replaced as part of maintenance)
5. Fuel Injectors (mustang 19#)
6. Exhaust Header Gasket (had a leak)
7. AFM (replaced)
8. Engine Temp Sensor (replaced)
9. Throttle Position Sensor (replaced)


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

EN318isPDX

  • Hero Member
  • *****
  • Thank You
  • -Receive: 0
  • Posts: 650
    • View Profile
    • http://www.cardomain.com/id/ItotheAtotheN
bad idle
« Reply #26 on: August 01, 2008, 11:00:56 AM »
Quote from: AcSchnitzer318is;54131
Well another swing and a miss guys.  Replaced my TPS with no luck.  Only thing left for me to change are the intake gaskets... but I sprayed a bunch of carb cleaner around the intakes... got no change in results.  I think I am going to take it to my local indy to have them do a smoke test and find any and ALL leaks the car has.  Will keep the updates coming.

1. ICV (replaced)
2. Vacuum Leaks (did TB heater delete and replaced hoses)
3. o2 Sensor (replaced)
4. Plugs & Wires (replaced as part of maintenance)
5. Fuel Injectors (mustang 19#)
6. Exhaust Header Gasket (had a leak)
7. AFM (replaced)
8. Engine Temp Sensor (replaced)
9. Throttle Position Sensor (replaced)


Have you checked your fuel pressure yet? Replace your fuel filter? Wouldnt you feel dumb if you pay a shop to figure out you need a 10 dollar fuel filter :eek:
WTB 97+ M3 Front Strut Assembly and 97+ M3 Control Arms (caster is important)
WTB Driver side Diamondschwartz fender PST

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #27 on: August 02, 2008, 12:22:05 PM »
Quote from: EN318isPDX;54144
Have you checked your fuel pressure yet? Replace your fuel filter? Wouldnt you feel dumb if you pay a shop to figure out you need a 10 dollar fuel filter :eek:


LOL yes I would feel dumb.  But I did replace the fuel filter when I had a line go bad on me back there.  Also replaced the injectors.  Have not replaced the fuel pressure regulator or fuel pump but I wouldn't think that they would only affect the car on first start.


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

AcSchnitzer318is

  • Sr. Member
  • ****
  • Thank You
  • -Receive: 1
  • Posts: 469
    • View Profile
bad idle
« Reply #28 on: August 04, 2008, 07:13:56 PM »
Car is in the shop... will keep everyone updated... pray it does not cost me an arm and a leg :)


"A good memory for quotes combined with a poor memory for attribution can lead to a false sense of originality."

EN318isPDX

  • Hero Member
  • *****
  • Thank You
  • -Receive: 0
  • Posts: 650
    • View Profile
    • http://www.cardomain.com/id/ItotheAtotheN
bad idle
« Reply #29 on: August 04, 2008, 08:07:16 PM »
Quote from: AcSchnitzer318is;54349
Car is in the shop... will keep everyone updated... pray it does not cost me an arm and a leg :)


I hope it turns out to be something simple!
WTB 97+ M3 Front Strut Assembly and 97+ M3 Control Arms (caster is important)
WTB Driver side Diamondschwartz fender PST