The idle stop screw is not as "sacred" as Ford would have you believe. In fact, early Ford EFI systems had a "base" idle adjustment spec on the screw. IIRC it was 400 rpm on my '86 Turbo T-bird. But people got to monkeying with them so Ford put locktite on the screw and warnings to NOT TOUCH IT. But it's not that critical. I still set them on my trucks with the IAC valve disconnected, I usually go for about 500 RPM. I usually have to do this because some PO has fiddled with it and got it all out of whack. The 460 I just put in my F150 was idling at 1500 RPM warm because some PO had screwed the base idle screw all the way out and broke it off in the process.

 

I figured it wasn't that big of a deal like Ford lets on. When I turned it in about 1/4 of an inch or less, it didn't really do nothing. I didn't unplug the IAC valve when I did it. I took the air intake hose off the throttle body and the plate still closed all the way, didn't stick or anything.
It's back to normal now. I don't have a tachometer to read the rpm. I'm just listening trying to get it back to as close as it was before I messed with it. I'm guessing it's around 900 rpm or so. It has dual exhaust on it also.

I bet that sucks having a idle rpm level at 1500 rpm!

 

You may have a point here, but can't setting the screw too far in [so that the butterflies aren't sealing all the way] create unmetered air at idle which would then cause stumbling or other issues? I'm thinking it would be comparable to a vacuum leak.

 

By "it's not that critical" I did not mean you could put it anywhere you want, I just meant if your base idle with the IAC unplugged was 400 or 600 RPM, it wouldn't make any diff.

BTW if the air is going by the throttle plates, then it is being metered in a MAF system like he has, so, no, it would not be like a vac leak.

OTOH, if it was an SD system, there would not be any diff between a hole in the throttle plate and a hole in the intake, except the air going thru the hole in the throttle plate would be filtered. However, if you screw in (or out, depending on your lexicon) the throttle stop screw to raise idle, the TPS is going to see this the same as you pressing the gas pedal a little bit, so I don't see how that is going to cause a stumble. It's just gonna make it so that the IAC cannot control the idle the way it wants to.

 

My truck has the speed density system. It don't have a mass air flow sensor.

 

Cool. Glad you got it worked out.

 

Me too. Now I think my EGR tube line is cracked or something I gotta loud ticking noise.
The EGR valve line was cracked on my 97 Ford Explorer 5.0 it had a ticking noise also.

 

There is no mystery about a stop screw. The reason the factory warns you is to basicly not muck it up If you want remove your throttle body. Remove the butterfly plate and inspect.If there are extreme ridges in the bore after you clean the TB. You will have to replace it If it looks well not so bad get the finest stelll wool you can Take a few swipes aroundt the ridge and please afew swipes Your are trying to accomplish smoothing the ridge and NOT deburing it Do the butterfly aame way Clean it up litely making the edge smooth NO More Don't try to remove any bad scars on the BF edge this very important. Assembly the TB Adjust the hold down screw gingerly tight until your final torgue down Move the BF up and down without any hang ups. Bring the screw out until you feel some resistance when its shut Then carefully turn the screw in a 1/8th of a turn. if you still feell it bind go in at 1/8th turn increment. If you have to turn it in past 9/16th of a turn you can consider that TB finished. Remember it has no bearing on your idle. Reset your PCM If your a layman and lack a scan tool disconnect the battery. If you have an alarm and a lock out you have to reset the PCM a different way and that's another story. It will take about 30 miles or abit more to relearn the new TB position. But don't trip if it idles abit high Keep driving and all will be fine Ive personally done about 8 cars this way. There is another way and when I have time I will post the pictures of a factory procedure however you must have $5600 for the jig

 

Congratulations & welcome to FTE.

You've managed to resurrect a 4 year old thread & address a guy who hasn't logged on to the site in 2.

But we're glad you're here...

 

My bad My old eyes are not what they used to be and long hours in the shop does not help I misread the date,thought it was afew monnths old.
Jim

 

Not a problem. Stick around & contribute.

 

I accidentally adjusted the throttle stop screw and ever since my truck jerks when i go to accelerate . .... what can i do to fix this

 

after messing up the throttle stop screw adjustment... how do i adjust it back....?? please help! 02 escape xlt 4wd!! ive replaced tps and rear end and it still jerks