i have a 3.1 rs and it keeps stalling
the reason that i think it may be electrical is because i find that when i turn my rear defrost on my battery gauge drops dramatically
also every time my turn signal ticks the battery gauge moves
i cant seem to figure out what it is

ps. when i am parked and push my brake pedal or turn my wheel my rpms drop down (dunno if that helps)

 

The rear defrost sucks tons of juice so a drop in voltage is normal. The drop in rpms when you turn the wheel is normal too because the power steering pump is operating and stealing power from the engine. The turn signal thing is also normal. My car exhibits all three of these and I have no problems.
What other things are happing when you stall?

Matt

 

Matto's right. Those are all normal symptoms (except the stalling). Does your computer have any error codes? Usually something that will stall your engine will also set a code.

What are the conditions in which it stalls? Cold engine? warm engine? tranny in drive? neutral?

 

If the battery is weak or dying, it could be putting an unreasonable amount of strain on your alt as well. When you turn on something that sucks alot of juice, the alt may not be able keep up and also dropping voltage to the ignition as well causing the stalling. Bad alternator could be the problem as well. Just guessing.

I would 1st start with making sure all your power (pos. & neg.)cables are clean and tight at the battery, alt. and starter. If the problem persists. Have the battery and/or the alt tested.

 

my car seems to only stall when inching forward with the wheels cut and applying the brake. my car used to stall when taking it from drive to reverse as you would when parallel parking but i got a vaccum leak taken care of and that seemed to take care of the problem. the battery is about 3 or 4 months old because my dumb @$$ did my stereo install at night and kept dome light on w/o car running.

my alternator looks pretty dingy and that was also what i was suspecting to cause these stalls

ps. i know nothing about ignition systems or starters....

 

What is your voltage gauge reading when it stalls? It's normal for voltage to drop some when you turn on high amp accessories, or when you put a load on an idling engine, but if it drops too far the alt may not be up to snuff.

Take a look at your voltage gauge once with the key on and engine stopped. Take note of where it's at. That's your voltage with no alternator current. It should be roughly 12 1/2 volts. With the car running, if the voltage drops below that point, it means you're pulling more current than the alt can produce, and that extra current has to come from the battery.

You don't by chance have underdrive pulleys on it, do ya? Some of them underspeed the alt, and that will cause reduced alt output at idle.

You might also check that the idle speed is set properly, and check for proper IAC function.

 

no my car does not have underdrive pullies and i just replaced the whole iac a week or two ago

 

Did you get the IAC set properly?

Here's some directions
https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

 

i am not any way shape or form a mechanic and know very very little about how to do things....i just get info about my car and see what others think may be wrong with it when a problem occurs.

with that said....

i didnt change the iac myself i took it to my local garage. i assume that they set it right but ill ask next time i go down there. i think that i am just going to end up replacing my alternator and if the problem isnt fixed then ill keep searching for the answer

ok black, i just checked the volts (using the gauge in the car) and w/ key turned but car off the volts showed around 12.5. when i started the car they went up to about 15volts. i let the car idle for a little while and as time went by the volts kept dropping. what does this sound like to you?

 

If I had to guess, I'd say they just stuck it in there, without setting it. If you think about it, it makes sense. You had a component that is greatly important to your cars idling ability replaced, and now it won't idle.

Do your volts come back up if you bring rpm up to or above 1500rpm? If so, you're probably seeing the normal voltage drop that occurs with any electrical load with the alternator at idle speed. When the volts dropped, did they go under 12.5? If not, then the alternator is probably not suspect. FWIW, even with a dead alternator, the car should run for as long as the battery has enough power to crank over the engine. If you want to see proof of that, unplug your alternator , and go for a short drive.

Alternators are a little to pricey (my opinion) to go replacing them just because they are "suspected" of causing a problem. I'd get it tested first. Any parts store that sells alternators should have the ability to test them. Some places even have the equipment to test alternator and battery while they are still in the car. An AutoZone near where I used to live could do that (don't know if they all do). At the very least, they should be able to test it off the car if you bring it in to them. When I test an alternator that way, I usually go to that store's driveway, and borrow their tools to pull out my alternator in their driveway. It only takes 5 minutes.

 

very good point

so tell me a little more about this paper clip thing....i read the thread but i have no idea where the thing is located

 

second post down, this thread https://www.thirdgen.org/techbb2/sho...ht=aldl+pinout

The aldl is behind a little black panel (1 1/2 inches by about 3 inches), that pops out of the under dash panel on the drivers side. It's basically right above/in front of your right knee, as you drive the car

 

That's exactly how it's done, there is nothing to set w/the IAC. The IAC is non-adjustable. The throttle stop is however. From the factory, the throttle stop is sealed and non-adjustable (because GM engineering is so damm good and something like that never needs adjusting )
When you do a minimum idle air adjustment, you're setting the IAC fully closed (ALDL diag mode and then unplug IAC) then tweek the throttle stop screw to get the minimum idle set, the ECM then adjust the IAC accordingly to get/hold it's preset idle speed.
As long as the throttle stop is within a reasonable tolerance of the min idle speed, the IAC has no problems controlling a steady idle but, no matter what you do, you can't adjust what the IAC does (unless it's behavior is able to be changed in the PROMor physically altering the IAC pintle)

 

Oh, I wouldn't go that far. Sometimes it needs adjusting because the cars previous owner thought it would help to open it way up. Or engine mods have reduced idle vacuum, and you need to open up your minimum air a little more.

But you are correct, it's not the IAC that is being adjusted here, it's the minimum idle speed. Now that I look at it in that light, it shouldn't need to be adjusted because of the IAC being replaced, but if it isn't a bad thing to consider when diagnosing idling problems

 

I was only being sarcastic about the throttle stop never needing adjustment (I'm not a big fan of GM's engineering on certain things). It wasn't anything towards what you said really.

With this said..
My guess is that with the PS pump working hard to cut resistive wheels (lack of movement makes it even harder on the pump) and hitting the brakes (dragging on the alt.), the poor little v6 (not badmouthing the v6 either) is just having a hard time producing the power at idle to keep up.

 

I didn't take it that way.

But you are right. Unless the something changes the flow characteristics of the motor, it shouldn't need to be monkeyed with.

If the minimum air is set too low, it's possible the IAC can't compensate enough for the load of the alt/ps pump.

back to 90v6 rs: what is happening when you do the paper clip thing is you are closing the IAC all the way. Then, when it's unplugged, your setting the absolute minimum air allowed for idle. If your minimum idle air is set too low (which could very well be causing this problem), the car may not even get enough air to idle. This would actually be a good sign, as it would suggest we've found the cause of your problem. Be sure to start with a warm engine (necessary to get setting right). If it won't run at all when the iac fully closed, just crank the idle stop screw open 2 or three turns. It should then run with an abnormally high idle, and you can work the adjustment backwards (from high idle down to the spec speed)

good luck

 

what should the idle rpms be and would you say that this paper clip thing is something that a total novice is able to do?

 

I think the emissions label under the hood says what the minimum idle speed should be. If not, set it for 450 or 500...that should be good. Remember to have the engine already warmed up when you set it, too.


As for whether or not a novice should do this, it depends on your confidence level. Do you understand the reason for each step in the procedure? This is a simple thing that is good to learn on. I say go for it. There's nothing to lose, and I don't really see a way anything could get goofed up, so there's no real risk of breaking anything either.

good luck

 

as of right now, in park, my car (warmed up) idles at about 1000.....

 

According to what I have (doesn't mean it's right though), minimum idle should be 550 ±25 rpm and the TPS voltage should be .55 ±.10v

W/o the IAC plugged in and it set fully closed (using the mulit-function diagnostic apparatus..... papaerclip ), the engine should be idling at one of the above rpms.
Once the IAC is plugged (back) in, the ECM uses the IAC to adjust the idle to a preset speed.

 

Dude, I gotta get me one of those. Can I order one from summit or jeg's?

 

with the iac and everything else hooked up.... after warmed up.....what should my idle rpm be?

 

WITH the iac hooked up, it will vary, depending on what the computer wants it to be.

During the setting process, WITHOUT the iac set up, you should (with a warm engine) manually set it to mfr. spec. (not sure, but probably in 450-550 range). Look on the white emissions label under the hood. idle speed setting may be listed in there.

To give you a ballpark figure what to expect, with the engine warmed up, in neutral/park, and no accessories running (ac, etc), it should idle between 750-1000. I can't give you an exact figure, because it changes depending on conditions, as determined by the ecm. If it's outside that above range, there may be something wrong somewhere.