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View Full Version : IACV Cleaning, Vacuum routing, Fixing idle problems

xsparc
10-12-2008, 07:33 PM
So my car started having the stupid bouncing idle and sometimes dying.

I did all the basic stuff like looking for vac leaks and sparying TB cleaner into the IACV tube. Nothing seemed to help really. It was very intermitent.


Here is an exploded view of the IACV after i cleaned it
http://i121.photobucket.com/albums/o229/x86sparc/PA110266.jpg

There is a brass set scew covered in epoxy that you can take out to really get everything clean. BE VERY CAREFUL NO TO STRIP THIS.
http://i121.photobucket.com/albums/o229/x86sparc/PA110274.jpg

When reassembling this just tighten it so the valve is just barly on the seat and the spring is just touching the valve. Mine was loose.
http://i121.photobucket.com/albums/o229/x86sparc/PA110271.jpg
http://i121.photobucket.com/albums/o229/x86sparc/PA110272.jpg

Next just set the idle screw to half way.
http://i121.photobucket.com/albums/o229/x86sparc/PA110273.jpg

Last just recoat the brass set screw in some new epoxy so it wont move
http://i121.photobucket.com/albums/o229/x86sparc/PA110275.jpg

Now just reinstall it and adjust the idle per the FSM



Ok so here is where it gets really fun. If you are in the 5-10% like me and this DOES NOT fix the problem, go check EVERY vacuum line. There is a crap load behind the head and under the intake mani. I replaced all of them and rerouted some to make it easier to get to. This seemed to fix it... for about 30 minutes.

Looking over everything else i found that the EGR valve seemed to be sticking open sometimes when the car went back to idle after reving it. You can check this but putting your finger under it and seeing if it seats all the way when you rev the engine. Sometimes mine was not.

The EGR was not the problem either. When i turned the car off and pressed the diaphram it ALWAYS seated right. I hooked a vac guage up the the vac source for the EGR and noticed sometimes the vac would not go back to zero.

The only thing that could do this is the EGR control solenoid. Either is is bad (closing too soon) or there is a weak signal going to it making to close too soon. I havnt check wither out yet but thats the only thing that can cause it to hold a vac when it shouldnt.

For right now i just have it unpluged and everything seems to be ok. Rock solid idle at 700 but the EGR is always on, kinda makes your car bog abit but doesnt die at idle.

You can always just remove the EGR or just plug the vac line to it, but if your in cali like me, you will never pass smog like that.
surreybc
10-12-2008, 08:39 PM
Nice pics. I guess you dont have an aiv in california. the computer does the job of aiv in california. somebody made a tutorial on making second grounds for some of the valves. (not the iacv as it isnt grounded.)

my car has a bit of stall problem when the air pressure is low. i doesnt stall but the idle drops to far at stop etc.. I did get a new iacv but it had the wrong plugs. Im selling the car in a year or so so lost interest in chasing this darn problem.
xsparc
10-12-2008, 10:48 PM
yes there is an aiv in cali... however you can just get the aiv plug from nissan and your good on that end.

grounds cant fix everything
ROIDMONKEY
10-12-2008, 11:26 PM
im having that problem . I just ordered a new IACV to see if i finally can get rid of that damn problem. ive changed a bunch of crap check for vacum leak and more... have that problem since my first SR setup and this is anothe setup but using that IACV from my old setup...
miklos
04-30-2009, 10:14 PM
Isn't there a gasket for the IACV to use when bolting it back on?
carcrossy
04-30-2009, 10:50 PM
Isn't there a gasket for the IACV to use when bolting it back on?


yeah, ive seen it for sale. there was no gasket originally. same with egr.
dreaMervaj
08-05-2010, 08:21 PM
Bump from the dead but I had a question.

How did you guys take off the epoxy? It is hard as sh!t.
s13-ghost
08-09-2010, 08:40 AM
ok guys i got the here seems like we all have the same problem. dis is wat mine does i turn my car on and on cold days or at night my car has trouble turning on and then when it does my rpms drop low wanting to die but as the guy mention when i come to a full stop my car wants to dies its turn off on me 3times n it starting tot bother da f outa me. idk but when i move around the tps wire around it seems to drop idle too and dis is my 2nd tps by the way any help
locoluna825
08-12-2010, 02:47 PM
Make sure that the AACV on the IACV is engaging when your key is in ON position. Take it off. It unscrews. and put some power to it from your battery. If it doesnt the aacv is shot. If it does. check the harness coming to the AACV with a multimeter and check to see if its getting voltage.

Your tps may be loose. make sure the bolts on it are tight. or you might be getting a bad connection with the harness end. but wigglin the harness may cause the whole thing to move so make sure its tight.
JonathanPrem
10-19-2010, 07:24 PM
I need some help. I did my 5 speed conversion but during the conversion i broke the FICD solenoid and got it replaced. But i have problem know. When i start the car it die if i dont touch the throttle or if its warm day the throttle jump pretty bad for 5 seconds or so. I got the idle adjusted to 750ish but know its back up at 900. Second problem is that when im in gear i can never be under 2k?