1990 na idling at 1200-1500...

[everpresentnoob]

So I have been having nothing but issues with my z for a while... Fix one thing to find something else has gone wrong, or think Ive narrowed down a problem, only to discover it wasnt the problem...
Well, here's my newest. My car idles high. Like 1200-1500 rpm. I replaced my iacv when I puled to old one to clean it and found the AAC solenoid was not working. I have sprayed wd40 on every vac line I worked near and some that I didnt work near looking for air leaks. nothing. Everything seems good. sprayed the IACV housing where it bolts to the block, and that is good as well.

I know how to set the idle, pull the yellow plug, agjust big screw to get idle to 650, plug back in. But even with the screw all the dang way in my idle is only coming down to 1200ish.

What the heck can I be missing??

[z.Leinbach]

Go on Facebook and look in the Z32 page addicts and enthusiasts page curing erratic idle file.

[everpresentnoob]

Been searching and searching for a vacuum leak on my car causing the high idle.. Got the brilliant idea today to pull the MAF off, block off the intake at that point and then blew smoke into the intake to hopefully find where the leak is. well bingo!! Found two leaks. First was the balance tube on the drivers side. the little oring had come unseated from its groove causing a nice leak. Fixed that. Still idled high, although not as high. Started looking for another leak and I found one. Pretty sure I know whats leaking and why its leaking, but not sure how to fix it..

when I removed the IACV I think I broke something...

On the outer and upper bolt from the IACV there was a metal ear that went around to the front of the IACV that I could not maneuver the dang thing around to remove the valve from. So I got mad and bent the ear out of the way. Did not realize that it was spot welded onto a vacuum hardline. the second leak is from this line. I think that when I bent the ear it ruptured the hardline at the weld. the line is a solid metal line that travels up the back corner of the valve cover and then goes into a 4 " rubber line that then goes back into a hard line and attaches to the balance tube small nipple by the large hose that feeds the air regulator and then the IACV.

My issue now is how the bleeping heck do I pull this hard line out to fix or replace it? under the iacv area i see it is "T'd" into another hard line. My thought is if I can get a pair of snips or something in there I can cut the hard line that I think I ruptured, and then get a longer rubber hose to make up the difference in length from the original hose.

I have pics, of the offending line, but cannot for the life of me figure out how to post them here... Normally used photobucket in the past but thats not viable now..

[everpresentnoob]

Ok tdrying this.....
In this pic you can see the hard line that I think I ruptured, red circle. Its the brass colored pipe right beside the wiring harness going down. the blue circle is the ear that I had to bend.


In this one it shows the top part of the rubber hose attaching to the hard line that goes to the ballance tube nipple, red circle. In yellow I atempted to draw the rest of the rubber line as well as where it attaches to the hardline I think I broke.


This is just another view of the rubber line that attaches to the hard line I may have broken.


Its really hard to get a pic of this thing as its buried pretty well, and moving things out of the way is rather difficult... I know to fix it Im gonna have to move a bunch of stuff, but Im not even sure what the hell this thing is or if I can just cap and eliminate it...

[everpresentnoob]

Ok, found a pic online that has a nice clear unobstructed view of the hose Im trying to describe... red circle. the blue arrow is pointing at the ear that I bent. Disregard all the lines that are numbered... I found this pic on aus300zx in the write up for a plenum pull and water hose bypass write up.



and because I stole their pic heres a link to the write up... http://tech.aus300zx.com/Rear_Water_Hos ... ement.html

[fastVG30DETT]

That point on the balance tube gets blocked off during the carbon canister delete. If you don't find a fix for the hardpipe, you can bypass it. Just search for the delete.

[everpresentnoob]

Yea... I have spent a few hours this morning on google and finally came to the same solution. tonight I am going to grab a few vacuum plugs, plug that one and the one on the bottom of the TB essentially bypassing the canister and see if that makes any difference in my idle issue. Im hoping it does.... after fixing the last leak under the balance tube I can get my idle to about 900 with the AAC unplugged, but not quite low as it should go. Hoping this solves it. If so Ill just do the full Canister delete.

Thanks for the response.

[fastVG30DETT]

That sounds about right. Good luck! Hope it works out.

[everpresentnoob]

well last night it was raining pretty good and I am lucky enough to only have a gravel driveway to work on my cars in but I still managed to go out and cap off the vacuum nipple at teh throttle body and on the balance pipe as If I was doing the carbon canister delete. I was able to get my idle down to 900 with the AAC unplugged and once plugged it it went to 1000 or just a little higher. So its getting better!! This weekend Ill try more smoke and see if I can find another leak. Or I might just see if I can live with a 1000 rpm idle... I mean thats only 250 off of optimal right? thats not to bad....

[everpresentnoob]

So I pulled the air regulator out today... Opened it up and found it was nasty inside as well as the disc that moves inside had somehow come off the pivot so it was no longer moving as it should. ran 12V to the connector and let it sit for a few mins and the thing did nothing. So Ill be replacing this part soon. Also the hoses came apart as I was pulling it out so I have to replace those too. I read in here that it was 5/8ths heater hose so on the way home fro work I grabbed 2 feet of that. Way to big... So tomorrow Ill pick up the correct size hose and put this busted regulator back in just to see if with the hole blocked off now where my damn idle is. Really hoping it is back down to 650 where it should be...

[everpresentnoob]

well first, 5/8ths heater hose was to big to use for the replacement hoses on the air regulator... Had to use 1/2 inch. put the regulator back in, wrestled the hoses on and my car now idles at 850. Im calling it a win. Ill drive it a bunch this weekend to see if my drive-ability issue was solved and hopefully after 4 damn months I can start driving the thing now that summer is over!!