IACVU Removal and Cleaning with pictures.

Catman · Jul 8th, 2004, 11:04 PM

Last week I removed the Idle Air Control Valve on my Sentra. It was full of carbon, and after cleaning it the car did not stall or hesitate when warm like before. So far, about a 75% improvement overall. In my enthusiasm, my first post was confusing. I am a little dyslexic, and words can get jumbled in my head. So, in the interest of clarification, I removed it a second time, took some pictures to outline the procedure I used. I am not a mechanic. Just a poor DIYer. I cannot say all info is accurate. I did use Alldata as a reference. I am showing you all I know. Before removal of the IACVU, I did try to adjust the idle. It did not help, so I set it back to where it was. I also tested the Auxiliary Air Control Valve using an ohmeter. It was supposed to be about 10 ohms. It tested at 10.5 ohms, so I assume it was OK. As a last resort, I removed the IACVU with great results. I think all the carbon that deposited on the spring caused the mechanism to bind, especially when the engine was warm, since after cleaning process it rarely stumbles or hesitates. I installed an aftermarket cruise control on my car. Ignore the extra cables, vacuum hoses, and the big vacuum reserviour. Hope this helps. This is my first time attaching pictures. Cross your fingers that is works!

fos160se · Jul 9th, 2004, 02:07 AM

No pic's yet - Please it would help me a lot because I plan to do it tomorow morning. If you can't post it send it to me fouchecj@nampak.co.za I realy need it before tomorow - thanks

Catman · Jul 9th, 2004, 11:51 AM

Sorry everyone. Brain overloaded. Was not able to get the pictures to display no matter what I did. I am able to email them. Will try to figure this out again tonight.

sno · Jul 9th, 2004, 01:38 PM

check out the newbie section to find out how to post pictures.

Catman · Jul 9th, 2004, 07:56 PM

Hope it works this time!

Catman · Jul 9th, 2004, 08:23 PM

Picture 0001 is the location, looking at the front of the engine, it is one the left side of the intake manifold.

Picture 0003 I am removing removing the wiring harness. I just sqeezed and moved the clips back and forth, then they pulled out. Then removed three bolts, and last removed the hose coming out of the bottom.

Picture 0006 is the AACV turned on its side. The top part with the purple plastic connector is the fast idle control solenoid valve. I did not mess with it. Alldata did not show how to test it. You can check the resistance of the AACV with an ohm meter across these two terminals (in the reddish brown plastic). It should read approximately 10 ohms. There are two small screws that hold this AACV to the entire unit. It has a plunger and a spring (the section with the lettering). You are supposed to be able to pull it out to see if the spring is broken. I could not get mine out, but it moved freely and the spring seemed to work. So, I just put it back together. This plunger pushes against what looks like another plunger, diaphram, and spring that is exposed to the carbon in the intake. That was filthy and binding.

Picture 0009 shows the spring after it was cleaned. Used throttle body cleaner and a toothbrush. Was careful not to use anything sharp. It looks like it has a diaphram that could be punctured. After cleaning, blew it dry with air. Seemed to move freely.

Picture 0029 shows all the crud in the intake manifold. I had some high temp RTV, so I coated the old gasket with a thin coat. Was able to get a good seal both times I installed it. Torqued to 5 ft. lbs. Used a 10 mm socket with a short adapter.

Put everything back together reverse of the way I took it off. This is on the 1.6 motor. I have no idea what it will be like on the 2.0 motor. I plan to clean this unit again during my next 30,000 mile throttle body cleaning, since it is exposed to similar carbon deposits. Hope that helps.

Catman · Jul 9th, 2004, 08:30 PM

One last thing. Thanks for your patience. Guess I was tired last night. Had good intentions, but 2 hours after I took these pictures on Monday a storm came through that blew down trees and limbs. No power for three days. Better late then never. Enjoy!

Catman · Jul 9th, 2004, 09:59 PM

I stand corrected. I double checked and Alldata did show how to test the FICD. Supposed to apply battery voltage to the terminals after disconnecting the harness. You should here a clicking sound. If not, then you can remove the solenoid (it looks like it unscrews) and check for a sticking plunger or broken spring. If it fails the above test it needs to be replaced. I did not check mine, but since it is running so well, I may skip that step. Just didn't want to mislead anyone in case your FICD is bad.

bast525 · Jul 11th, 2004, 10:01 PM

Thanks for that! Been hoping someone would post something like this since I first signed up here

Too bad for me that this is a 1.6 though... I have the 2.0 and the placement is a little different. Still on the left hand side of the manifold, however it's a bit lower down in the engine bay, and there are A/C hoses/pipes and I believe a power steering hose running in the way of it... VERY hard to get to for me. So I've been kinda afraid to try it. Gonna take another look today and really try to plot out exactly how to get to the bolts and get everything and be sure I can get it back in.

fos160se · Jul 12th, 2004, 01:45 AM

Thanks for the pictures, at least I know how the unit looks like. I tried to take it off Saturday morning but couldn?t get to the unit because I got the hi port motor SR20DE and to make things worse its also right hand drive which mean that the brake booster is in the way. I tried but couldn?t even get the 10mm in there , whish my hands were as small as a six year old.