Lost Idle

So this is the very 1st time my truck presented a problem in all the 12 years I owned it. But I caused it. The other day I was dickin around and adjusted the slack out of the throttle cable. Then I went and bought a rubber plug from the hardware store and replaced the "J" shaped resonator on the intake tube with it(and unplugged the EFI fuse for 20 mins. then replugged that) Everything was fine, till today when on the freeway, I was changing lanes to get into the fast lane and some knuclehead in a beemer-3 tried to shut out my opening-so I stabbed the gas and it kicked into second (at 60mph yikes, bad) but then as it got third I got ahead of him. Still everything was normal till I stopped in traffic and then realized I had no idle. No idle all the way home. Got home, and wound up adjusting the idle screw to bring her back to normal. She idles fine now, never threw a code, and runs precisely as well as ever.
So my question to you guys is WTH did I do to it-stretch the cable? Tweek the arm or throttle cam? And the other question is will she eventually sense the change and not like it?
I used to work on my own cars in the day but never once had to touch this one, and am not thrilled that I got my mitts in there where I shouldn't be messin'.
Thanks for any help.
Where ya at bamatoy

 

Rodger that buddy-and I do appreciate the direction! Nevermind anybody-I got help from the best (you all were gonna leave me hangin' anyway lol)

 

Damn bro, I am sorry that I missed this thread. I admit there are days that I am so busy that I miss a lot of the cries for help sent my way. If you ever have any problems, just shoot me a PM and I will usually always reply within an hour during the day, or shortly after in the evening.

Chris mentioned this thread so I will post up my thoughts here as well. When you mentioned taking up the slack in your throttle cable, it had me curious. I have done that myself before because face it, some vehicles do not actually get wide open throttle when you floor the pedal. Time and wear can eventually cause a cable to stretch small amounts, or bind. However it is never a good idea to adjust all of the slack out of a cable. I usually adjust mine to the point where I can rest my foot on the gas and not pull the throttle. This leaves a small amount of slack. Why would you want this? Because you also have a computer that controls your idle, and may need to close the throttle plates entirely for diagnostics and self calibration. Another issue with adjusting the cable too tight is that some TPS sensors will go out of range if the throttle cable pulls the throttle plates open too far. It is not a common problem, but I have seen it happen. the results are usually a default throttle position, with minimal or no power, and most of the time it will set a code for the TPS sensor out-of-range. Your sudden "WOT" acceleration may have done this. But after shutting it down and restarting, the sensor was within parameters, and all was good. I would suggest putting a little bit more slack into the cable adjustment and go drive it again. See how that works out for you.

Oh yeah, replacing that resonator is not always a good idea. it helps with things such as a suddenly closing throttle plate.

Sorry again for missing your post. I am beginning to think I need to start my own technical help thread....lmao.

 

Bama glad you jumped in here. Hey now ya know that you're read often and respected by lurkers like myself who actually seek the real and useful stuff in this forum.
I did return the cable back to its original position yesterday along with resetting idle. Call it retirement boredom or a need to tweek stuff on an engine like the old days-but I shoulda never F'd with perfection and regret it. Oh well, it still runs perfectly so really not a loss.
But since you & Chris both say that my idle is computer controlled, what is that screw I adjusted that successfully returned my idle called? Chris I think said it is a butterfly valve stop-I forgot that part of his explanation. It's the allen screw that sets sideways at front mid-left on throttle body. I went after that one because it was the only thing I saw that was making contact with an appendage on the throttle arm. Thanks again BamaToy for your input.

 

That is called your "stop idle". It is used at the factory, or sometimes by dealership techs, to set your base idle after doing certain repairs. For instance if you took your truck to me and I replaced your throttle position sensor, I would disable your Idle Control and set the base idle adjuster screw to about 600-650 RPM. That allows the minimal amount of air to get past the throttle plates if the entire control system failed.

 

The thing is, you are not supposed to touch that screw unless you are setting base idle with a properly running engine. If there is an underlying problem with the idle, then messing with that screw can cause all sorts of problems. You have to get the idle problem fixed first, without touching that screw.

 

ok I'll have to run it into the dealer and get it looked at. But I've got to say, after running around all day with it, it's very smooth and running just as right as always. I even have the idle set with that screw at an ever so slightly higher RPM than was stock, and it downshifts into 1st smoother, have yet to have that typical axle wrap clunk yet, and the 1/2-second cough I always had off the line is totally gone, as well as the usual hot start idle bog. Go figure. It's like it wants a little more idle to operate more flowingly. So if they wind up correcting this thing, I hope I don't lose what I seemingly gained by accident.
Hope this doesn't annoyingly fly in the face of your expertise, but it is what it is.
Maybe since no codes were thrown my little foible fell within the tolerances?

 

Yeah I feel like it's a safe move Chris taking your advice and BamaToy thanks again. This truck is just awesome-and pretty forgiving too. Chris, when I finally get a new vehicle, I'm keeping this truck. Rosie agrees-can ya beat that? The high step-in is killing her bad knee, but she doesn't want to see it go either. It's been that good to us.

 

I think Chris is right, run it like it is now, unless another problem crops up.

 

ok BamaToy appreciate that! Not thrilled about my dealer here-try to only use it for oil changes&brakes but leave the more serious stuff to the one I bought it from in Burlingame. So if I can stay outta there I will