installed some ignition parts, now idle sticks. WTF?

[astronut1885]

Hey guys. Yesterday I installed: MSD wires, dist. cap, blaster TFI coil, and dist. rotor, and a pair of Denso O2 sensors. I went on a trip to the pick+pull today for a new taillight, and every time I was in neutral, my idle was stuck at almost 2k RPM. At one point it was even pulling the car along in 4th gear with no gas. When it does finally come down, it takes a while, like it stops at 1500, at 1100, then finally drops to 700. This is pretty aggrivating, especially when you're sitting at a stop light and it won't come down from 2k. I didn't touch timing or TPS, so I don't know what could be causing this. I tried adjusting the idle screw, but it's at the point where the butterfly will bind if I back it off any more. Any ideas?

 

[86T-Top]

Check your IAC valve. When mine went bad, it would keep the idle stuck at 2K also. You can take your IAC off and apart and clean it with carb cleaner to get the buildup out of it. Make sure you didn't forget to plug anything back in that you unpluged.

Mario

 

[astronut1885]

It's freshly cleaned actually, and freshly replaced. Everything's plugged in, and it ran fine yesterday when all the parts went on. It does it more when the motor's hot then when it's cool, too. Maybe it's just being a bitch today, sometimes my car likes to remind me who's in control lol.

 

[kdog_x]

My car does the exact same thing. It'll run like new for about the first 1/2 hour or so. Then I'll pull up to a red light and it'll stick at about 2000 RPMs. After doing this about 5 times I actually jumped out and physically pulled the throttle forward and it dropped back down to about 750. If you figure out what caused this let me know, it's been driving me loco.

 

[jrichker]

See http://www.members.tripod.com/sparkplugs/idle.htm or http://www.mightyap.com/index.htm for some help on your surging idle.

Both sites point to bad TPS sensors as being the culprit in the surging idle that goes high and sticks until you shut off the engine.

 

[astronut1885]

My tps reads fine through the throttle cycle, but I know it has gotten wet before, and when it does it reads poorly. What I don't understand is A) why it only does it when the car's hot, and B) why it started doing it after I added all the ignition stuff.

 

[wrathchild]

I kinda have the same problem. I replaced the ect, act, egr positioning sensor and map sensor. When i got it started up it would idle fine as long as i havent moved. When i come to a stop the idle will hang around 1800 rpms and then finally after coming to a complete stop the idle will drop down to 1100 rpms. I cant get the idle any lower than 1100 rpms either. Ever since i built the motor it will not idle any lower that 1100 rpms. I can take the set screw out completely and it idles right at 1100.

I have replaced pretty much every sensor except the o2 sensors. They will b e replaced within the month.

 

[HISSIN50]

i will toss out something else, though highly unlikely..any chance you have a vac leak?

Jrichker, i did not have a chance to read your links (i will later. - since you are the computer man, would disconnecting the battery have any affect on things being re-learned, since he replaced some stuff? im wondering if something so simple might help him out.

good luck.

 

[wrathchild]

I have unhooked my battery 3 times now. Did nothing. Things are never simple for me though.

 

[astronut1885]

I did unhook the battery, and a relearn did cross my mind. I was having issues before with power loss and such, and someone mentioned a vac leak. maybe I hit something and made it worse. I need to get some carb cleaner and go hunting.

 

[HISSIN50]

sounds good. most folks have 15-20 inches on a stock set up (stock cam, etc).
good luck.

 

[astronut1885]

Well, I think I finally got it. I swapped back in the stock MAF, and that stopped the surging at startup and during idle. The RPMs still stuck around 2k, so I disassembled my IAC and cleaned it out good, and lubed it, but that didn't help. Then it dawned on me. I now have working O2 sensors monitoring the emissions. I have the FRPP idle adjuster plate that goes on the IAC, and I had it wide open , allowing more air into the motor than it wanted . It was essentially like the IAC being stuck open. I screwed it closed, and boom, no more sticky idle. It revs good, and has more power, which I attribute to having the right MAF directing the fuel flow. I might be buying a Tweecer off a friend, so when i get that I can reprogram the computer and put the Pro-M back on with the 19s. Isn't technology cool? I'll never have to buy a MAF again if it works. Until then, I'm stuck with the shrimpy stock MAF.

 

[HISSIN50]

nice work - i am glad to hear i was of absolutely no help at all (as usual).

 

[astronut1885]

I might still have vacuum leaks, hissing. you never know... and you were motivational support..lol

 

[HISSIN50]

i suppose my name is enough to motivate someone to look for vac leaks, huh? good luck hunting - i hate searching for leaks.

 

[astronut1885]

Well, I did't fix it. I took it out this morning and the idle kept climbing up and sticking. If I unplug my IAC and just use my adjuster plate, it idles fine, but if I plug in the IAC, it shoots the idle way up. What a pain in the butt.

 

[jrichker]

Back to the bad TPS... They don't last forever...

 

[astronut1885]

It got alot better today, did it less and less until it finally stopped. I think it might have been the computer relearning, because it did this same thing when the motor was finished. Hopefully it'll stay running normal. If not, I will look right at the TPS.

 

[astronut1885]

Well, I did end up finding some vacuum leaks, I tore a hose under the intake on accident, so that's fixed. I unplugged the battery yesterday to install the 3G alt, and it's doing the idle stick and surge again. It's gotta be the computer. A few days after my last post, it cleared up completely and idled like a dream. I hope it does again, only sooner. I need to get an A9L and get rid of this stinky ass conservative 93 computer.