Idle Speeds??

[dlmetzger]

This is related to the problem I was/am? having with my Vibe GT stalling at idle. GM's solution was to adjust the timing and idle speed. Previously, my idle was 800 rpms now it is about 1200 rpms. I was curious what other peoples cars were set at. I am just concerned that they didn't really fix anything and that whatever is wrong is just being masked by the higher idle setting. Just not acceptable in a new car in my opinion.Thanks,Dan

[d_m_kolb]

I can tell you for a fact if all they did was raise your idle RPM they didn't fix anything. The problem is still there it just might be masked by the higher RPM idle now. You should call and talk to the Severice Manager NO ONE ELSE and explain what happened and what they did. If that person wont do anything stop taking it to that dealership and find another Pontiac dealership. It will cost you nothing to change dealerships. I have done this myself.Your problem isn't fixed though and with you having a new car and under warrenty it should have been fixed right the first time. When you think about it, they can't ajust your timing. The computer does that. They can move the timing belt or chain where it is off one tooth either way. This is actually going to hurt performance since the computer will all ways be trying to put the timing where it's suppose to be and will never be able to do it because of them moving it. Plus if the idle needed to be increased the Idle sensor would send a message to the computer and it would ajust it. There for you still haven't gotten the problem fixed, it's now just masked until it gets worse and possably leaves you without a driveable car.Good luck with getting it fixed.

[emod50h51h]

I did a little research in on your idle problem, While your idle is controlled by the computer, the computer does not controll all the air that is needed to controll the idle. How the Idle Air Controll valve works is that a base idle speed, say 550-600 rpms is set when the throttle body is calibrated. this speed is obviously lower than what the desireable idle speed is. This is where the computer and and IAC valve come into play. the computer decides what speed the engine should idle at based on coolant temp, intake air temp, A/C demand vehicle speed and probaly another half dozen or so inputs. It then sends a pulse width signal to the IAC to open a passage that by passes air around the throttle plates. Longer the pulse width signal the more air that bypasses the more idle speed. I've been looking at the service info for the GT engine and it does not give a spec for the base idle speed. This is not unusual because our goverment considers any adjustment of this screw a violation of emissions laws. I do know from past experience if this base speed is to low due to misadjusment or carbon buildup that seals off the air flow around the throttle plate ,you will usualy get a stallon deceleration.The base idle or minimum idle speed adjustment is what they may have adjusted. Timing has no adjustment, your car has a crankshaft sensor and a cam shaft sensor to time your ignition through the computer and ignition module. While there is no adjusment some car have what is called crankshaft sensor variation learn. this is where the computer learns the position of the sensor and adjusts itself within the compuer th compensate for any varyations from top dead center. While I could not find any such info for a Vibe GT, The Service information may not be up to date. We often do the relearn process on cars, especialy after doing a update down load.I did see in the service ifo that it should idle down to about 850 rpm's with engine hot and left at idle for a minute or so, but there is some variables that you can't see or controll that could prevent this you would need a scan tool to be sure if all paramiteres are in place for this to happen properly. My Vibe Gt seems to idle about a 1,000 rpm but I haven't really watched it close yet. Sorry about the long winded spew. I'll try to watch it closer tomorrow

[dlmetzger]

I agree with you d_m_kolb but I don't think there is much I can do. This went past the service manager to Pontiac Service Department, then to the GM Tech Center. If it doesn't stall anymore there is not much I can go to them and complain about. Service departments here in the Detroit area are not what you would call "Customer Focused". They have a captive audience.Thanks for the info emod50h51h. I would be interested in anything you observe such as what happens when you come to a stop. It didn't stall yesterday. The idle varied between 1000-1200 rpms. It would imediately drop to 1000 when the clutch was in then bounced up some (I am thinking that is the idle control) then it would settle in at 1000-1200 rpms.Thanks,Dan
[Modified by dlmetzger, 7:43 AM 6/1/2002]

[d_m_kolb]

1000 to 1200 still seems high to me. I'm glad you contact Pontact customer service directly. I'm sure they will be more helpful than your dealership. You might even contact a toyota dealership since it's their engine in the Vibe. They might know right away what is wrong or could tell you what the Pontiac dealership should try.Good luck.P.S. Emod said everything I had all ready covered but was much more technical about it. Thanks Emod.

[emod50h51h]

Drove my GT to work to day, when I got home I forgot and shut car off right away and then I remembered to check idle. started back up about 2 min. after shut off, let run 3 min. in drive way A/C off and after the 3 min the tach needle was right on the mark just under the 1K mark. there maybe some variables that may prevent your car from idling down that far but should get there sometime.Also car was freshly spanked I forgot somthing at work I was taking to race track tonight for the car and had to go back and get it.

[vibb]

I have a Base Vibe automatic. It has a cold-start idle of 2000 RPM for about60 seconds, and a stable warm idle rpm of 650 RPM in Drive, or about 700 RPM in Neutral.The idle speed bumps up to 1000 RPM when the steering wheel is moved,or when shifting from drive to neutral. The elevated RPM lasts for a few seconds.