Username or Email Address
Do you already have an account?
Forgot your password?
  • Log in or Sign up

    VWVortex


    Results 1 to 12 of 12

    Thread: 2.0 people, does you car idle high when coasting to a light?

    1. Member
      Join Date
      Oct 22nd, 2007
      Location
      New Haven, CT
      Posts
      1,664
      Vehicles
      Mk3 windsor Gti 2.0, Mk1 Jetta 16v
      08-05-2013 08:27 PM #1
      My car has just always done this. I dont know how it happens, it just does and I never wondered why until now.

      When Im driving and Im approaching a light, cruising in 4th ill use the brake to slow down and then just put it in neutral and coast to the stop.

      The engine will idle around 1000 rpm until just after I stop completely, then it goes back down to 650 or where ever its supposed to be.


      Any reasoning for this


    2. Member crestfallen's Avatar
      Join Date
      Dec 2nd, 2010
      Location
      Wheeling, West Virginia
      Posts
      1,176
      Vehicles
      68 baja bug (sold); 96 Jetta Gls (LY3D); 94 Jetta Gls (LB5T) parted (RIP); 99 (mk3) jetta Gl (LN5Y)
      08-05-2013 08:37 PM #2
      Every one I've had/driven does. I believe it's to keep it from lurching/stalling if you were to release the clutch before you rolled to a stop. Could be mistaken though
      Quote Originally Posted by SiDGh2 View Post
      ""I've never been to the junkyard just to look if they got anything new this week"
      My 99 Windsor Blue project.
      http://forums.vwvortex.com/showthrea...one-from-three

    3. Junior Member jtman79's Avatar
      Join Date
      May 6th, 2013
      Location
      Halifax NS
      Posts
      37
      Vehicles
      1997 Volkswagen Jetta Trek, 2005 Saturn Ion
      08-06-2013 12:45 AM #3
      1997 2.0L Jetta does the same, close to 1000rpm until a full hult, pressing in the clutch or putting it in neutral. I don't see anything wrong with it, but hey, I'm dumb but typically i engine brake
      Last edited by jtman79; 08-06-2013 at 01:12 AM.
      One day i will own a not sh*t car, but not for a long timeeeeee

    4. Member OddJobb's Avatar
      Join Date
      Nov 6th, 2004
      Location
      Greenville SC
      Posts
      1,811
      Vehicles
      2004.5 Jetta GLI, 1995 Golf III City
      08-07-2013 10:31 PM #4
      All cars will do this. When the car is in motion and in neutral there is less parasitic drag on the engine.
      Quote Originally Posted by LG6R View Post
      I never understood this and don't take it personally because people come on here and say that all the time. But if you don't know what it is or what it does, why don't you leave it the hell alone?

    5. Member Sky-Fi's Avatar
      Join Date
      Jan 19th, 2008
      Location
      Charleston, SC
      Posts
      1,963
      Vehicles
      97 LG5R Jetta GLS
      08-07-2013 11:03 PM #5
      I rarely observe this since I downshift until just about idle in 2nd when coming to a stop. I only see it for a a few seconds until just after I have made it to a complete stop. As far as I can tell, that's normal. Less normal is if after it returns to ~850 where it should be, it goes back up over 1000 for no apparent reason.

      However, A/C running may make it idle a tad higher, or as I've noticed occasionally, when the SAI pump kicks on, that 30A draw will put a brief load on the engine thanks to the alternator, so it idles at 850, then drops to 650 when the load hits and goes up over 1000 to compensate and levels back out to 850 all in the course of 2 seconds.
      We need a series like this state-side. I'm in if there is one, or will be one. VW Cup 2014/5, anyone?

      Odometer: 157884mi | 249 full tanks | 78,161.3mi | 2,724.709gal | 28.68611mpg | US$0.10297/mi

    6. Member BFalk628's Avatar
      Join Date
      Dec 29th, 2012
      Location
      215
      Posts
      134
      Vehicles
      1999 Mk3 Jetta Silver Arrow 2.0
      08-08-2013 02:08 AM #6
      I have noticed this too and same as was said above about the AC kicking on but i have also noticed it will hang at about 1200 rpms after i go in reverse and then press the clutch pedal in. Dont know why and doesnt bother me too much though

    7. Member
      Join Date
      Oct 22nd, 2007
      Location
      New Haven, CT
      Posts
      1,664
      Vehicles
      Mk3 windsor Gti 2.0, Mk1 Jetta 16v
      08-08-2013 01:23 PM #7
      Thats weird< when my AC is on my rpms drop wayy down when I put the clutch in. I think its going to stall sometimes it goes so low.

    8. Member Sky-Fi's Avatar
      Join Date
      Jan 19th, 2008
      Location
      Charleston, SC
      Posts
      1,963
      Vehicles
      97 LG5R Jetta GLS
      08-08-2013 10:30 PM #8
      Quote Originally Posted by Mileperhr View Post
      Thats weird< when my AC is on my rpms drop wayy down when I put the clutch in. I think its going to stall sometimes it goes so low.
      Same, but we're talking about in neutral whilst rolling up to a stop. With the A/C on and starting to roll from a stop, you put a lot of load on the engine. I've almost stalled mine a few times with the A/C running.

      [Lots of text from here, most of it is optional/trivial, feel free to skip it]

      Anyway, I had another thought about this one earlier today, and it does actually make a lot of sense. There is still a reading coming from the speed sensor (VSS), so the ECU adjusts the idle up 2-300 RPMs for two reasons: a few more RPMs gives the power steering pump a little more power for steering and control, and a higher RPM gives you more vacuum for vacuum-assisted brakes.

      Someone asked me a few years ago why I learned downshifting pretty much from day 1. My answer has always been a multi-part/benefit answer:

      Part 1 is in modern fuel-injected engines, when the RPMs are higher than the throttle is asking the engine to turn, this is called "overrun." During overrun, the injectors either completely stop spraying fuel, or they spray less than they would at idle, so you waste less fuel coming down to a stop than you would if you just drop it in neutral.

      Part 2 is that by keeping the drive line coupled with the engine, in the rain or sleet/snow/ice, you have less potential for losing control since the tires are still "in contact" with the engine.. so if you start sliding in one direction, you can turn the wheel and apply some gas to pull the opposite way. This also keeps you from locking a wheel up if you don't have ABS (or making it much more difficult/likely to lock one up).

      Part 3 is that with the higher RPMs, it gives you more power-steering power to maintain control, as well as more vacuum for your brakes, so you don't end up having to stand on them with both feet unless it is an absolute emergency.. have you ever tried stopping a car that doesn't have power brakes? Or being the towed car that does the manual braking for both vehicles to keep the chain/strap taught? It's a lot of work, and downright scary sometimes.

      Part 4 is by having the engine do a lot of braking, especially if the A/C is running, you don't use your brakes as hard/much, giving them more life and keeping them much cooler. Unless you get ceramic pads, as the pads heat up, they wear faster. A couple of weeks ago, I was on the Interstate and had to get on them pretty hard a few times, and later that day, I noticed they felt A LOT different than earlier that morning. But around town, if you get on them once or twice pretty hard, once they cool off, you don't notice much, if any, change in how they feel. This is the reason why my pads have just over 50,000 miles on them and still have about half the material remaining. Hell, the rotor has more wear on it than the pads do, and I did new rotors and pads at the same time.

      So by downshifting, you end up doing a lot of things, and it also makes it less likely for the engine to stall or shut off for whatever reason until you're just about down to a stop anyway, whereby it wouldn't really matter from a safety standpoint if it does at that point.

      If you want to give it a shot, unplug the VSS on-top of the transmission and try rolling up to a stop in neutral again. It will probably be at 850 instead of just over 1000, because the ECU is not getting a reading from the VSS.
      We need a series like this state-side. I'm in if there is one, or will be one. VW Cup 2014/5, anyone?

      Odometer: 157884mi | 249 full tanks | 78,161.3mi | 2,724.709gal | 28.68611mpg | US$0.10297/mi

    9. Member
      Join Date
      Oct 22nd, 2007
      Location
      New Haven, CT
      Posts
      1,664
      Vehicles
      Mk3 windsor Gti 2.0, Mk1 Jetta 16v
      08-09-2013 01:05 AM #9
      Well lol it seems we also have the same driving habits. Obviously there are times when I just neutral coast it and thats where my question came from originally. I have driven a car with pump brakes (85 chevette) and I really cant say anything bad about that either. Coincidentally, I just got my power steering back online after at least a year of not having it.. which is a bit of an adjustment keeping control.

      But my original question came about because sometimes my rpms are up to around 1300 and sometimes they are 1000. But I think Ill just leave the sensors alone lol. I dont need something to break


    10. Member OddJobb's Avatar
      Join Date
      Nov 6th, 2004
      Location
      Greenville SC
      Posts
      1,811
      Vehicles
      2004.5 Jetta GLI, 1995 Golf III City
      08-10-2013 09:20 AM #10
      Quote Originally Posted by OddJobb View Post
      All cars will do this. When the car is in motion and in neutral there is less parasitic drag on the engine.
      I correct myself here. All cars don't do this. I decided to pay attention to this when driving my MKIV GLI yesterday. When in neutral and coasting the idle is right where it sits when the car isn't moving.

      Quote Originally Posted by LG6R View Post
      I never understood this and don't take it personally because people come on here and say that all the time. But if you don't know what it is or what it does, why don't you leave it the hell alone?

    11. 08-10-2013 02:39 PM #11
      Funny enough, my car idles / coasts at roughly 850 rpm all the time, even when the A/C is on it holds steady. I have a 99 Jetta Mk3 Wolfsburg.

      I used to downshift to lights / stops until I learned about the stress being put on the engine / transmission while doing so. It's much much cheaper to replace pads / rotors than it is to replace an engine or more likely a transmission, adding a few thousand miles onto my brake pads life isn't worth the stress for the drivetrain.

    12. 08-10-2013 02:54 PM #12
      Mine does it on occasion. At speed, push the clutch in, and it may drop to idle (850) or a little above (1000). If it's a little high, a light tap on the throttle will settle it.
      Quote Originally Posted by mhjett View Post
      I'm convinced you commuted through a salt mine.
      Quote Originally Posted by Mk3_Addicted View Post
      Bariman82 is the king of rust patching...He is the guy you want to talk to.
      My take on fixing a rotten mk3.

    Posting Permissions

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