I think I idle lower than normal....

[L0ckett]

As the title states, my idle seems awfully low. From what I've read through searches the car should normally idle around 950 or so (correct me if I'm wrong). My car will idle when started cold around 1042 dropping to the 950 range. When in gear, still after cold start, it drops to the 860 range. Now when the motor is warmed up and I'm at a stop it will idle between 673 and 763 and when I put it in park it idles around the 745 to 830 range. These are my rpms from what is displayed on my Neo and comparing those numbers to the tach itself it seems pretty dang close. I'm not sure if this is relevant info or a completely different issue but on my boost gauge I sit at roughly 13hg vac when in park (both when the motor is cold and warm) and when its in gear it sits at exactly 10hg. I've been told that I should be around 18 to 20hg. This doesn't seem normal to me but I'm also new to dsm's and it's also the first turbo car I've owned so I'm still learning all the norms and oddities.

 

[MLutin]

Whens the last time you did a boost leak test? Also check your idle screw on the throttle body.

 

[L0ckett]

I did a boost leak test about a month ago and everything checked out just fine with no leaks.

 

[MLutin]

Well your maf could be going bad too.

 

[Tranceworx]

Something is definitely off. Vaccum should be closer to 18-20 at idle. Typically during warm up my car idles closer to 2000RPM and slowly backs down to 750 on full warm.

 

[rich3389]

Factory spec is 750 RPM +/- 100 RPM.

 

[blktalon3]

I'm an auto and mine does close to the same thing. When your in park your vacuum should read higher than it is, but it will drop when you put it in drive. The same with your rpms, you could set the idle for 1000 rpms when your in park but it will drop when you put in drive because their is a load on the motor.

 

[DSM1G90]

I sit at 750 rpm when it's all warmed up sitting at a light in neutral...where it should be...

 

[my dreamt dsm]

My apexi rev reads around 750. It's normal.

 

[L0ckett]

Okay thanks for the info. I still don't understand why my car sits around 650 or so when it's warmed up and in gear.

 

[crimsondragon]

If you're idling normally yet seeing low vac, there's an unmetered leak somewhere. Do a BLT.

 

[L0ckett]

Thanks guys. I did do a boost leak test and there were no noticable leaks. Any other suggestions that would cause a low vac?

 

[2gGSXEclipse]

it also depends on who tuned ## car and what A/F ratio its running at idle, cause ive seen on mine when you make it richer the idle will go lower, leaner idle goes higher, and i mean no like 25 rpms it changes 150-200 rpms. what your A/F ratio at idle if you have a WBo2

 

[crimsondragon]

double post

 

[crimsondragon]

Thanks guys. I did do a boost leak test and there were no noticable leaks. Any other suggestions that would cause a low vac?

Do another. Unless you changed to some hardcore cams or skipped a tooth of timing, there's no other way vac can be lowered without an increase in RPMS unless your boost/vac gauge is off.

 

[L0ckett]

I'll definately do another blt when I get a chance. I gotta find my tester first. Also I don't have a wideband or logger (I know, they're next on my list) so I couldn't tell you my a/f ratios or any more vital information.