hey, my car usually idles around 500rpm during the summer, and 600 rpm in the winter... im pretty sure it used to idle at 650 all the time... is there anything i could look into for this? it drives normal, though it feels a lot slower than last year. maybe im just getting used to it.
could it be the fuel system? as far as i know, the fuel filter has never been changed or cleaned (but i do add injector and filter cleaner every 5K miles) and the injectors havent been looked at since the car was new.
any thoughts?
if you want to change the idle, see if there is an idle adjusting screw on the throttle body.
If you try to adjust the idle at the throttle body, the computer will attempt to compensate -- possibly messing up your mixture or timing. It's possible that you've got a problem with a sensor somewhere, or maybe even with the tach itself. (I know if my car ever tried to run at 500 rpm, It would shake itself apart or stall, whichever came first.) Otherwise, the only proper way I've heard to change the idle is to reprogram the ECM (i.e. with HP Tuners).
Edited 1 time(s). Last edited Thursday, December 06, 2007 10:12 AM
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im not to worried about it, as much as i think its time to clean something... it occasionally shudders on take-off when cold... last winter it would almost stall out and then recover when starting to move from a dead cold start.
Yeah mine is the same way, idle's around 500-600. Something isnt right. Goina check a few sensors and what not and go from there. Theres no engine lights on but just seems alittle weird idleing. Also driving, when going up a hill in overdrive i notice a slight miss of loss in power or fluctuating. I have no clue what it is yet?
Quote:
If you try to adjust the idle at the throttle body, the computer will attempt to compensate -- possibly messing up your mixture or timing.
So sitting with my foot on the gas to bring the rpms up to say about 1500 for it to warm up faster. (Very cold mornings) Is gonna mess up my timing? wow GM must have really messed up designing our timing system. When you adjust idle at the throttle body all your doing the same thing granted the locations are different. All that adjusting screw is, is just a stop. Also if adjusting idle at the throttle bady is bad, why do they put adjusting screws there? hmmmmmm......
I just must be dumb.
PS. I think my muffler bearings are going, doesnt anyone have a left handed screwdriver i could barrow to take the cover off to get to them?
i might have a left handed screw driver for you...
sweet i cant find a store that carries them. wait........ are we talkin about the same thing????
i thought you were joking about the left handed screw driver thing so i played along... haha
Tinkles wrote:So sitting with my foot on the gas to bring the rpms up to say about 1500 for it to warm up faster. (Very cold mornings) Is gonna mess up my timing? wow GM must have really messed up designing our timing system. When you adjust idle at the throttle body all your doing the same thing granted the locations are different. All that adjusting screw is, is just a stop. Also if adjusting idle at the throttle bady is bad, why do they put adjusting screws there? hmmmmmm......
I'll admit I was simply passing along info I got from old threads. My understanding is that adjusting the throttle body adjust screw wouldn't actually change the ECU's sensed throttle position, whereas holding the pedal would.
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my truck had low rpms and i adjusted the timing and they went up to 600 and it felt a lot more responsive.14 second responsive
Tinkles wrote:Quote:
If you try to adjust the idle at the throttle body, the computer will attempt to compensate -- possibly messing up your mixture or timing.
So sitting with my foot on the gas to bring the rpms up to say about 1500 for it to warm up faster. (Very cold mornings) Is gonna mess up my timing? wow GM must have really messed up designing our timing system. When you adjust idle at the throttle body all your doing the same thing granted the locations are different. All that adjusting screw is, is just a stop. Also if adjusting idle at the throttle bady is bad, why do they put adjusting screws there?
the idle on our cars is controlled by an Idle Air Valve (not sure if thats exactly what it's called). its on the TB and it opens and closes to allow more air thru when the car is idling. the screw is exacly that, a stopper, not an idle adjustment. it keeps the throttle plate from closing past the fully closed position. if you pull the intake off the TB you will see that at idle the throttle plate is fully closed (no air gap). the computer uses the idle air valve to control idle so if you adjust the screw and open the throttle plate you could mess up the timing or fuel or something because it thinks the plate should be closed when its not.
So answer me this: Why is it adjustable?? By what your saying the "stopper" should just be a precsion machinced surface, not and adjustable screw. And isnt the TPS on the other end of the shaft that bolts to the throttle plate????
The TPS is going to read how much the plate is open, thats its job. You turn the screw, throttle plate opens a smige, and the TPS reads throttle just a smige higher.
Quote:
I'll admit I was simply passing along info I got from old threads. My understanding is that adjusting the throttle body adjust screw wouldn't actually change the ECU's sensed throttle position, whereas holding the pedal would.
The TPS(Throttle Position Senser) on the other end of the shaft will read the adjustment.
Again off topic, but does anyone know where to get aftermarket performance muffler bearings??? Im at a loss none of the local part stores have them, they just look at me like im crazy.
Tinkles wrote:So answer me this: Why is it adjustable?? By what your saying the "stopper" should just be a precsion machinced surface, not and adjustable screw. And isnt the TPS on the other end of the shaft that bolts to the throttle plate????
The TPS is going to read how much the plate is open, thats its job. You turn the screw, throttle plate opens a smige, and the TPS reads throttle just a smige higher.
i agree that it would make sense for it to just be a precsion machines surface but what happens when a steel tab stops against a machined aluminum surface repeatedly and forcefully. the aluminum will wear and the throttle plate will be out of adjustment. then you would either have to get the surface on the TB built up and remachined or buy a new TB. the way its designed if the aluminum wears slightly it is as simple as ajusting the screw to get the plate back to fully closed
