Engine Stalling Problem

[Flashover]

I'm pretty sure there has never been pure water in the cooling system. Every year I get an inspection, I have the mechanic check/add/replace all the fluids.

For the battery symptoms I have never had a problem starting the car and all electrical accessories work fine with no problems. The headlights dim for about a second (then go back to full blast) when I turn on the blower or A/C.

As for the engine, it seems to run and feel the same as since I first drove it. It picks up amazingly, can still pull some heavy stuff and I drove up a pretty steep hill today with no problem (I didn't let off the gas this time until I was pretty much up).

When the alternator was replaced, I honestly don't know what kind/model he put into my car. All I know is that the car runs. I had it replaced because the car was sitting for a while and no one was driving it (occassionally driving it). Battery was changed and still didn't work so it was brought to the mechanic and he replaced it.

 

[Pontisteve]

Well, if the car runs fine then all is well, right? The IAC motor could be taken off and cleaned inside the non-electrical half of it, that might help. The symptoms you mentioned are a little too vague to really pinpoint things, but we could be talking about a compressor that is maybe starting to lock up (go bad), or possibly just a corroded battery terminal.

The rust I saw on the compressor clutch could just be rust if you have a northern car. A worn out belt auto-tensioner could cause the alternator to charge inconsistently. The fan speed issue could be a blower fan motor starting to go bad. Too many maybe's. See what the car does, and report back.

 

[Flashover]

Alright so I finally got a chance to clean out the IAC and it was DIRTY, the cleaner liquid all turned brown and kept pouring out.

I started it and it started a lot smoother than before and no more clicking noise/dimmign headlights from the blower.

One more question, is 500RPM too low of an idle? Like if I pull up to a red light and hold the brake?

Also thanks to everyone who helped, I really appreciate it!

 

[Pontisteve]

500 rpm is too low. Chances are it's supposed to be around 650 or 700. But could also be a misleading tachometer. Does it FEEL like it's idling too slow?

When you start the vehicle cold, the normal routine is that it idles fairly high at first, like 12 - 1400 rpm, and the RPM steadily drops as the engine warms up, until it finally bottoms out at around 650 - 700 rpm. This is all in park, starting car cold, and not touching anything until it warms up.

Using carb cleaner and some sort of small brush, clean everything inside those 2 holes in the IAC, especially around the valve head that separates those 2 chambers.

 

[Flashover]

I started it up this morning and the RPM was about 1000-1200 and after a few minutes of driving, when I put the car in park before I turned it off it was a little above 500RPMs.

The car feels "smooth" like it's nice and quiet and when I accelerate it seems fine.

I had my brake pad and rotor changed about a week ago and since then the RPMs seem to run lower than before. For example, at 40MPH I used to run about 2500RPMs but now I run about 1500RPMs or so. Maybe that's a factor?

 

[Pontisteve]

Just to know the engine behavior, I would try starting it up cold, and leaving it in park while watching it warm up. The engine should start around 1200 (or more if very cold out), and slowly drop down to the desired idle rpm. I'm not sure what that is in your car, but it's usually around 650 rpm. Tach accuracy could contribute to an error here.

There's nothing on a rotor or pad, or in that area, that contributes to engine RPM. The large difference in RPM you mention sounds like the difference between being in 3rd gear or overdrive.

If you feel you have cleaned the IAC valve thoroughly, and it's pretty much dead clean, and if you don't have any more stalling issues, or issues with idle fluctuating, then I would say your main problem is solved.

 

[Flashover]

I tried what you suggested and the engine felt smooth and everything else seemed fine so I guess my problem's fixed.

Anyways thanks for the help, saved me a ton of money!