95 Eclipse...idles erratically

[vzfox]

erratically <~~spelling.

with the a/c running the idle is around 1200 rpm and with the a/c off it will idle at 2200 rpm's. what should i look at and test? it starts and drives smoothly.

2.0L DOHC (non turbo)
5 spd

[david-b]

Test your IAC and TPS. I'm going to guess the IAC though since that controls the idle. If you have a Haynes manual it shows you how to hook a voltmeter up to it and check the resistance. I think pin 1 and 3 IIRC... but a book says better. Sorry I don't have it here though.

[SilvrEclipse]

Check for vac leaks as well.

[vzfox]

Originally Posted by SilvrEclipse

Check for vac leaks as well.

I did find one hard plastic vacuum line that was broken. I replaced it and now with the a/c running it will idle smoothly at 800 rpm. But when i turn the a/c off, the idle will become erratic again.....jumping from 1200 to 1700, back and forth over and over until i turn the a/c back on. I searched all over the engine and found no other vacuum lines broken or cracked.

Where is the IAC and TPS on my car? i havent bought a manual yet, but intend to soon.

[david-b]

IAC and TPS are on the throttle body, facing toward the firewall. Buy the book and it shows all the sensors and how to check each one. Pays for itself time after time. It's all online too, but you really have to look for it.

That's weird, because the cars will usually do the EXACT opposite with the A/C on. Not sure.

[vzfox]

Originally Posted by david-b

Buy the book and it shows all the sensors and how to check each one. Pays for itself time after time

I went to purchase a Haynes manual yesterday and found that the book covers 1995-2005 models. I asked the clerk and he told me he owns a 96 model Eclipse and has the same manual. He told me the Haynes manual was useless for our model of Eclipse and that book only has a couple things I might be looking for. I put the book back on the shelf.

Anyone else here have the same Haynes manual, and has it helped ALOT with 95-99 model Eclipse's?

[david-b]

Originally Posted by vzfox

I went to purchase a Haynes manual yesterday and found that the book covers 1995-2005 models. I asked the clerk and he told me he owns a 96 model Eclipse and has the same manual. He told me the Haynes manual was useless for our model of Eclipse and that book only has a couple things I might be looking for. I put the book back on the shelf.

Anyone else here have the same Haynes manual, and has it helped ALOT with 95-99 model Eclipse's?

I have the Haynes. I had the 4g63, 420a and the 3G V6 motor in there. Has never done me wrong in he 4 years I've had. Hell, it's so beat up and dirty the thing is hard to read and you can't touch it without dirty.

[vzfox]

I took the IAC out that is located just below the TPS and cleaned it and the air intake housing and throats with carb cleaner. I put the IAC back in and plugged it back up. Start the car now and it idles at 4000 rpm steady. I let the car run like that for about a minute before getting worried that I might cause damage if I continue at that high of rpms. It never went down, even when tapping the gas pedal.

While I was cleaning the IAC, I depressed the "nozzle" completely down. I turned the key on and let it sit for a few seconds before starting it back up so the "nozzle tip" would extend back out. It just idles at 4000 rpm steady now.

Now what?

[vzfox]

Originally Posted by vzfox

I took the IAC out that is located just below the TPS and cleaned it and the air intake housing and throats with carb cleaner. I put the IAC back in and plugged it back up. Start the car now and it idles at 4000 rpm steady. I let the car run like that for about a minute before getting worried that I might cause damage if I continue at that high of rpms. It never went down, even when tapping the gas pedal.

While I was cleaning the IAC, I depressed the "nozzle" completely down. I turned the key on and let it sit for a few seconds before starting it back up so the "nozzle tip" would extend back out. It just idles at 4000 rpm steady now.

Now what?

Here is what I found when I took the IAC back off...

It had not extended at all. It was completely open allowing max air flow...causing high idle rpms. Now the question is why wont it extend...

I cant pull the tip out physically and when its plugged in it wont extend. The tip does however screw into the IAC module. I can unscrew it and make it longer (extended), but I dont think its suppose to be that way.

I tested the four prong connector going to the IAC using a multimeter. I grounded the black (ground) end and turned the ignition to the on/run position. Three prongs tested around .08 volts and the fourth prong tested at .28 volts. I then applied 12V from the battery to the IAC itself going from one prong to another, one at a time to see if the tip would extend....nothing happened.

So....have I tested the IAC and connector correctly? What else should I do or check for before condeming the IAC?

[YAMMAN]

sound like you need an IAC. replace it.
that little thing is a motor and the computer controls how far in and out that pintle moves. if it doesn't move when you applied power to it, then it's F__ked.

first check if it works with 5V or 12V. then test it one more time (and make sure you are on the right pins). while you have power to it, tap it with a screwdriver or something to shock it, and check if it moves.

if it doesn't move at all-replace it
if it moves only when you hit it-replace it
if it move one way and when you change pins, it moves the other way-then it's still good. look somewhere else.


SORRY DUDE...I DIDN'T SEE YOUR OTHER POST

GLAD YOUR PROBLEM IS FIXED

[Eclipser80]

Ok so I have the same problem on my 2.0L non-turbo, It idles high at about 2-3k and sometimes it surges between 1500-2500. I replaced the Manifold Absolute pressure sensor, the Idle Air control, the Intake Air Temperature, and the Throttle position sensor. There are no vaccum leaks anywhere and all the spark plugs are good. The only other thing I could think of is to check the wiring controlling the systems. Its as if the IAC quivers but doesnt want to work. If the wiring is good then the only other thing is to check if the Computer is the one thats messing up.

If theres anything else I missed please let me know and the solution.

[Eclipser80]

Along with all of the above I got the Cel code of P0505(IAC Valve System Fault) even after installing the new IAC and resetting the ecu.

[SilvrEclipse]

Then your problem lies with with the IAC more than likely. Check the wiring around the EGR pipe to make sure it hasn't burned threw

[Eclipser80]

Just went out and checked, it's all fine. My dad said that another problem with this model is a capacitor in the ecu leaks and destroys the board could that be the culprit? Other than that the only thing is to check everywire make sure they all work.

[LandoAWD]

Smell the ECU and inspect it. If it smells like fish, or you find popped caps, it is the ECU to blame.