IAC and base Idle

Topic: IAC and base Idle (Read 1046 times) previous topic - next topic

IAC and base Idle

March 12, 2009, 11:40:40 PM

Ok I have read through this several times and still have yet to get my car just right, still wants to idle 1000 to 1500 based on temp. 2.3 t in an 86 xr7. Base timing with spout removed is 10 deg, TPS is showing 9.1 v. First question is when you set the base idle, should the iac be plugged in or not? With it un plugged and the idle at 700, when you plug it in the idle goes to 1200. No matter where you put the idle screw, hell take it out, I still get 1000 rpm. Whith it unpluged I can can back the idle off enough to kill the car. After much reading, and checking for air leaks, I decided to pull the iac and clean it. It was not dirty but i did notice i could blow from one side to the other so I seperated the solonoid from the valve. With them seperated I could not blow through. Looking at the solonoid part of it I could see there is a spring in the end of the actuator that is slightly stronger than the spring in the valve (which does not seem to be very strong btw). When I mate them together it opens the valve very slightly. Is this normal? Is the IAC bad or am I just an idiot? thanks for the help and the wealth of info on here!!!

IAC and base Idle

Reply #1 – March 13, 2009, 12:12:09 AM

:D yes your an idiot:rollin: jk

now,, go back and take a new reading on the TPS green wire to ground with the key on only.

if you have any voltage above 1 volt,,,,,,,,,,,you are WRONG and you just found your problem:D

now,, since you seemed to be completly ok with the tps showing 9.1v,, explain exactly where each meter lead was , how they were connected and where did you get your ground. YOu might help us help you by explaining this mystery voltage.

with a 9volt reading to ground,, you have an open tps so start there.

once you plug in a new or spare tps, just let it dangle and start the car up,, if the idle is better, move on to proper tps installation as well as modification to the mounting holes (ie- chainsaw / rat tail / round file) so you can mount the tps snug. After it is mounted, you can rotate the tps either way to obtain > .6 to .9 volts DC on the green wire to ground.

IAC and base Idle

Reply #2 – March 13, 2009, 04:15:48 AM

Well oh great bitter one???? It was a typo much like the one you have there on line 6 of your reply. It was indeed .91 volts. Still does not explain it. I read plenty about how to set a tps, but thanks for the tip. I think the problem is in the iac, would anyone agree?

edit: green and black wires!

IAC and base Idle

Reply #3 – March 13, 2009, 12:21:29 PM

Quote

if you have any voltage above 1 volt,,,,,,,,,,,you are WRONG

Acceptable voltage range for the TPS is actually .6V - 1.1V...The ECU takes a base reading every time the vehicle is started....WOT settings are 2.71 Volts + base reading.

Have you run codes at all?

IAC and base Idle

Reply #4 – March 13, 2009, 04:22:58 PM

I have no codes being thrown. Kinda why I am thinking iac. The car runs really well. Nice smooth pull through the rpm range. Just a high idle. Is the IAC supposed to be cracked open a little when unpluged?

IAC and base Idle

Reply #5 – March 13, 2009, 04:39:22 PM

Quote from: Superdavesds;261402

I have no codes being thrown. Kinda why I am thinking iac. The car runs really well. Nice smooth pull through the rpm range. Just a high idle. Is the IAC supposed to be cracked open a little when unpluged?

Do you mean you have an 11 code or no check engine light?

IAC and base Idle

Reply #6 – March 13, 2009, 05:42:30 PM

Sounds to me like the EEC is activating the solenoid to step-up the idle.
Question is why would it do that?

IAC and base Idle

Reply #7 – March 13, 2009, 06:16:47 PM

Quote from: softtouch;261422

Sounds to me like the EEC is activating the solenoid to step-up the idle.
Question is why would it do that?

It is opening slightly even if it is unplugged. I had it off and on the bench. When you mate the sol and the valve, it opens about an 1/16". Maybe that is normal, I don't know.
And yes I meant no engine light, I read on here somewhere before how to pull the codes. Not sure where it was at. Link?

Edit: I can pull codes tomorrow or maybe tonight and get that info back to ya!

IAC and base Idle

Reply #8 – March 13, 2009, 06:38:49 PM

Does the engine light come on when the key is in the on position?
You do need codes if possible. It would explain more if you have them.