i just installed an 00vi, but i tried to start up and my idle rpms kept bouncing up and down. up to ~2.5k and back down, bouncing in about 1-2 second increments. then i thought maybe my throttle cable was too tight so i went out to pull on it and my rpms climbed to about 4k and i shut if off. any ideas?

i used the 5th gen TB and plugged in just one iacv plug like SDot did in this thread:
http://forums.maxima.org/showthread.php?t=463248
and the other 2 plugs going into the 4th gen iacv previously were left unplugged. guys help please i need my car tomorrow. thanks.

 

Did you try to adjust the TPS via.. http://vbxmaxima.8m.com/tps.html

I think your best bet is to get the IACV adapter, and run your 4G IACV because of the two remaining plugs for the idle control.

 

okay, so i started it up again. rpms start @ 1500, then slowly climb. and then after a few seconds, it starts fluctuating between 1500 and 2000 rpm.
the thing is, i took it for a drive, and this rpm jumping happens at idle AND while i'm driving, which is a pain.

with that said, is it still an iacv problem? i used a 4th gen lower and the gaskets (the lower/upper gasket looks to be real thick piece of rubber), but it looked like the 5th gen upper has it's own thin rubber around the holes. i wonder if i may have a leak there and maybe i should just remove the 4th gen rubber gasket?

 

I would really check the TPS if it is also occuring while driving. Your speculation about the two gaskets being installed together may prove something leaking through there, but that would have to be tested to see if it made a difference.

 

Double gaskets might be a problem. Did you try to turn on w/o iacv? Or w/o tps(only do this when car is warm)

 

hey i just checked the TPS. i swapped out the one on the TB for the one from my 4th gen since i know it was working, but i got the same rpm fluctuating problem. i don't have a voltimeter so i couldn't check it or anything, but i tried swiveling the tps and the rpms are still jumping. even if i swiveled the tps and tried it and it didn't help, would calibrating it help?

also i removed the 4th gen gasket between the upper and lower also and that didn't seem to help.

as for the vacuum hoses, does it matter whether they are connected to the intake before or after the throttle body? i have most of them connected to the intake manifold, and 2 (the one to activate the VIAS, and another EGR related one) connected to the intake before the throttle body.

 

On the intake = fresh air. After TB = vacuum. BIG difference.

 

i just calibrated the tps, its okay now. i haven't left my engine on for more than a few seconds but it seems the rpm jumping has died down, and now it just idles really high ~3000rpm.
i disconnected the iacv plug, and at startup the rpms shot up to 3000rpm, held fo r a few secs, and then slowly crept up, so i shut it off b/c i got scared.

so what needs to be hooked up to the vacuum, and what needs fresh air? on the 4th gen setup all the fresh air connections were a larger hose to the valve cover, and a smaller one that is egr related. i kept those connections the same and added the small hose that goes to the VIAS. everything else i'm pretty sure is hooked up to the intake manifold somehow.

 

so i tried starting with the iacv and w/o the 4th gen iacv harness plugged into the 5th gen iacv and the results were similar. ~2700 rpm upon start up and then it creeps up to 3k, and then i just shut it off.

not sure if it will start jumping anymore, but it's not jumping upon start up like it used to, probably because i calibrated the tps.

any ideas?

 

That's correctly only three hoses will got before the throttle body and everything else will be vacuum lines. What made you want to use the 5th gen IACV. I just did mine recently and with the adapter plate everything works perfectly. Otherwise did you make sure that the little screw on the throttle body is not slightly holding the throttle plate open?

 

Are any of your hose clamps in the way of the throttle plate motion keeping the plate slightly open?

 

nothing blocking the plate. after i calibrated the tps, it seemed that fluctuating idle upon start up went away, but now it just shoots up to ~2700 rpm and then climbs slowly. after it goes over 3000 rpm i just shut it off.


i used the 5th gen TB because i read this thread: http://forums.maxima.org/showthread.php?t=463248
and it seems to take care of the iacv, so i wouldn't need any adapter plates.

could my iacv be busted? i suppose you can use an adapter plate for the iacv along with the 5th gen TB right?

there's a little screw on the TB that can hold the throttle plate open? i was unaware of that and i'll check in the morning. the plate looked fully closed when i put the TB in and the cable has a little slack on it after i hooked it up, so i doubt the TB is open.

i'm wondering can a leak cause this really high idle rpm? i reused my lower IM to head gaskets, they looked okay but could that cause this problem? if i have a leak somewhere i have no idea where to start. i may just go back to stock.

 

between the TB port and the plate mechanism there is a 8mm adjustment screw that will allow you to adjust idle. Make sure that the screw is fully counterclockwise so it isnt in anyway touching the plate mechanism. listen for some vacuum leaks, they are really easy to hear, and tell where they are coming from.

 

Yeah, the idle trim adjustment screw. It's how a lot of people with 00vis with slightly mangled IACV setups adjust their idle. The screw stops the throttle from closing all the way, so it would actually cause more slack in the throttle cable if it were causing a high idle.

Edit: beat me to it.

 

Okay this happened to me when I did the DEk swap last week, its a vaccum leak, adjusting the TPS didnt do crap for me, it only made it worse in terms of how high it idles. The TB screw didnt do anything either.
The only difference between my problem and yours is that you're running the 5th gen IACV while I'm running the 4th gen. Once I removed the 5th gen IACV and blocked off the holes, it stopped the surging and it idles steady around 650-700. Might want to look into running a 4th gen IACV or just without running one at all and block off the 5th gen, I think thats the problem.

 

How well does yours adjust to AC and PS?

 

I'm using the 4th gen IACV so its plugged in. No problems there but for some reason I have starting issues, before I had a vaccum leak on the passenger side so it wasnt providing enough vacuum to my brake booster but it starts every time. Now I re installed the vi and theres no leak (as far as I can tell, I'm deaf to a vacuum leak now) but it wont start unless i hold the throttle for a couple of secs to keep the rev's up, after that it idles fine and the a/f is at 14.7 before it bounces from 16.1-21.0.

I do notice that on the old DE, when its cold starts it at least keep my rev up at 1500rpm for a bit and drops to normal but right now it dosent on the DEK, plus when that happens it shows on my SAFC the Throttle is about 2-3% but now its always at 0 at start up. I think I might have to adjust the TPS.

 

well, with the 4G TB there is a coolant temp meter which determines the temperature at which the coolant is and adjust with a fast idle cam. The 5G TB does not have this fast cam(so it seems) so the idle isnt adjusted for cold starts.

 

Thats why its so weird... the car started up every time before I reinstalled the IM and I didnt have the 5th gen IACV bolted on the TB but I knew I had a vacuum leak becuase I was runn lean at idle, I could hear it and my brakes were fading. Now my idle A/F is normal, brakes are back but it wont stay on without my help... I didnt change the 5th gen TB which like you said doesnt have a fast cam.

 

IM surprised you were able to get the car to stay running nicely without a plate at the bottom of the TB with the IACV removed.. Did you happen to tap anything into the same line as the brake booster?

 

well the thing was i didnt make a plate, I seal the two hole with RTV silicone, the gray stuff. Its holding fine... The brake boost was T with the 4th gen IACB to the reay nipple of the 00VI but when I the IM off the car, I noticed a hole below the nipple and it was where it was leaking. I sealed it up, just connect the booster to that nipple alone, reloacted the IACV vacuum and everything seem to be working fine, no CEL and decent idle. Again, I'm def to hearing for a vacuum leak now so I cant tell if I still have one or not For all I know I may have one somewhere else and its affecting the starting issue.

 

what does a vacuum leak sound like? and could the 5th gen IACV on the TB be what's causing the leak?

seeing as a i don't have an iacv adapter plate, i may just have to go back to stock. sigh.

 

Vacuum leak sounds like a really high pitched whistle, if it is vacuum it disappears when you accelerate slightly.

 

hmm, i don't think i have a high pitched whistle. could a iacv that is stuck open cause these symptoms?