Idle too low

[kentb]

just when i start the vehicle idle is about 1k, but after a few seconds or minutes
it goes down to 525 -570. that will be my idle rpm throughout my whole drive.

is there a fix for this?
i've tried the throttle cable ziptie mod and that doesn't work.

vehicle is 2000 ford explorer sport 4.0L SOHC, automatic

thanks in advance!

 

[kentb]

anyone?

 

[jlsparky7]

Your idle is supposed to drop about 500rpm after your engine warms up. The vehicle runs rich when its cold so it can stay running easier. After it warms up (45 secs-1min) or so then your idle should drop to right around 500-600. You have nothing to worry about.

 

[kentb]

Your idle is supposed to drop about 500rpm after your engine warms up. The vehicle runs rich when its cold so it can stay running easier. After it warms up (45 secs-1min) or so then your idle should drop to right around 500-600. You have nothing to worry about.

oh ok, but is there a way to surpass this? i actually want a higher idle, about 800.

 

[CHEESYPOOFS]

I thought it was supposed to be around 650-750 or so. It could be your IAC valve. Pop it out and see how nasty it is. You can kind of clean these with electric component cleaner from your local auto parts store. Usually i'd say replace the gasket but i searched for half an hour and couldnt find just the gasket (go figure :S) so i guess just wipe it clean with some gentle cleaner or if you felt so bold you could use a sheet of gasket material to cut your own. You can buy that stuff at auto zone and use ur old one to trace a new one and use a scalpel to cut it out (make sure to be as accurate as possible as not to impede airflow or not create a complete seal). Whole deal may help with your problem and the cleaner and gasket stuff wont cost you but about 10 bucks.

 

[Willard]

Why would you want a higher idle? If it doesn't die at idle, then what is there to worry about? All you would be doing is wasting gas. Having an idle just over 500 rpm is perfectly normal. Mine has always idled there, and it's always been fine.

 

[kentb]

Why would you want a higher idle? If it doesn't die at idle, then what is there to worry about? All you would be doing is wasting gas. Having an idle just over 500 rpm is perfectly normal. Mine has always idled there, and it's always been fine.

i just want a higher idle because i have a High output alternator and at 500 engine rpm it doesn't do much.

 

[Willard]

i just want a higher idle because i have a High output alternator and at 500 engine rpm it doesn't do much.

Then get an overdrive pulley for the alternator. You can't adjust the idle RPM on these trucks without an engine tune. The computer controls it.

 

[kentb]

Then get an overdrive pulley for the alternator. You can't adjust the idle RPM on these trucks without an engine tune. The computer controls it.

oh ok. i have a 2"(3:1 ratio) overdrive pulley already. most H/O alternators come with that.
im working on getting a 1 5/8" overdrive pulley. but that still won't get me to 2400 alternator rpm unless i increase the idle.

 

[2000StreetRod]

closed throttle stop

There is an adjustable closed throttle stop (screw) on the throttle body to keep the throttle plate from closing all the way and sticking. You can adjust the stop so the throttle plate closes less but the PCM will attempt to lower the rpm via the IAC valve. Eventually you will exceed the lower range of the IAC valve and the rpm idle speed will increase to what you desire. If you then cycle battery power, the PCM will "learn" the new closed throttle TPS voltage.

One caution about increasing the idle speed with an automatic transmission. An increased idle speed usually equates to an increased ATF temperature which if too high can shorten the life of your transmission. I notice you live in a hot zone but even there 800 rpm should not be a problem.

 

[PIHB]

your idle is fine with ur alt. Ur battery will give you plenty of amps for thumping music.
don't tamper with ur idle screw who ever mentioned it is an idiot. Ur idle is normal don't worry about it.

 

[2000StreetRod]

the "idiot" responds

your idle is fine with ur alt. Ur battery will give you plenty of amps for thumping music.
don't tamper with ur idle screw who ever mentioned it is an idiot. Ur idle is normal don't worry about it.

I agree that adjusting the throttle plate stop screw is not the preferred method to increase idle speed. The best method is with a custom tune. The alternator overdrive pulley is a reasonable solution for insufficient alternator output at idle.

The method I described is from the Ford Motorsport procedure for adjusting the idle speed for racing engines.