IAC question

[fordmuscle395]

I was just wondering...
When i start my car I usually have to crank it twice to get it to run and is usually followed by rough idle until you drive it for a little . One of the things I'm looking at is the IAC. So I disconnected the IAC while it was running...should it act different? Also, I know on most cars when you turn on the A/C, the idle changes to compensate, does the idle change on these cars?

 

[Jack's95gt]

Another thing to look at is the fuel pressure. Rent a gauge (Autozone) if you don't have one and watch it through the startup and idle, and shut down. You should be around 35- 40 psi and it should hold that after shut down.

 

[HISSIN50]

On the same fuel note, you can try cycling the key a few times before ever cranking the engine over (to build fuel pressure). If you do this and then it starts immediately, that suggests a pressure issue.

The IAC will compensate your cold idle, and loaded idle (like when the AC is on, as you noted). The hot (non-loaded) idle might not be affected, depending upon how your mechanical idle is set.

Good luck.

 

[fordmuscle395]

I cycled the key a couple a times, like you said. Turned the key over...started up, but immediatly started losing idle speed, luggin' and crap, till its just on the verge of dying then picks itself up (w/o me touching the throttle) and idles fine. what do ya think?

The check engine light has never come on. Im gonna hook a scanner up to it to see if its throwing any codes, also Ill probably try that fuel pressure tester.

 

[HISSIN50]

Codes and FP testing definitely are next steps. It can still be an IAC issue but because it's tough to test an IAC on your own (it has a square wave output), you kind of replace one after deductive observations.

Good luck.