Idle issues

[z32pilot62]

Okay so I just got done putting a newer engine in my 90 2+2 and she is idling at about 2200 and will sometimes fall off to about 1500 and them come right back up and pulse like that every about 2-3 seconds. I haven't had a chance to check timing (dunno how on these cars - search function fail), haven't had a chance to check codes because i really needed to get it out of the shop it was in. What could be the problem?

Rundown of things I did while the motor was out:
TB Coolant line bypass
Egr delete - got a jwt chip in the comp now
AIV delete
PRVR delete
Carbon Canister delete
5-speed swap

Mods already on the car when i bought it:
Pop charger
Cheap hard-pipe kit (ebay special)
KingZ panel

Input is greatly appreciated

[z32pilot62]

Okay so went and got the car from the guys shop and went and adjusted the IACV all the way in and now its idling at 1400. Still havent had a chance to run codes... i know easy deal, but it doesnt pulse anymore so thats a plus.

[Milton'Z Nissan'Z]

High idle is most often associated with a vacuum leak. If you have to adjust the AAC all the way, pretty good chance this is the issue as what you are doing is cutting the idle air down by adjusting the screw. Pressurizing the intake is the easiest way to find leaks.

Second thing to check is if the throttle is binding, often happens at the TB's where the front PCV pipes come out of the valve covers. If they are loose and work their way out, they will cause the throttle to stick open a bit.

[z32pilot62]

Other than the balance pipe, throttle bodies, and the inlet pipes, where else is there vacuum ports? I have put vacuum caps on all of these locations when I did all the deletes that I did. I did them to prevent vacuum leak problems in the first place so I am finding it hard to believe that it is a vacuum issue but maybe there is a port that I have over looked? Also i just checked my PCV fittings and they are not interfering with the linkage at all. Ran codes and getting a 33 but that still doesn't explain the high idle..

[DanDrath]

make sure the vacume cap didnt brake on the big vac line that comes out of the drivers side. I dont remember what its for but its a curved one and its like about the iacv. Mine broke and i had to make a cap outa a blot sillacone and vac line. Check that one out i guess its got a lot of suction and withthe rubbeer stretched its easy to brake

[z32pilot62]

Ya, thats where the carbon canister dumps into the intake. I did the same thing there that you did. Weird thing I noticed earlier is that when I just blip the throttle it will go back down to like 800 like it should then come back up to 1400 gradually. Also a crazy thing its started doing is every time I start it, the windshield wipers go once then stay off...

[z32pilot62]

Any ideas guys?

[evildky]

kinda sounds like a bad air regulator, it's the thing between the aicv and the ballance tube

[z32pilot62]

From researching what you are saying on the air regulator, if it is bad would it not make the engine idle up when I start it cold? My cold start is still working properly it just will not idle back down all the way once warmed up. Could the air regulator be getting stuck when it closes? Also, I sprayed some carb cleaner around every possible place I could think that there would be a vacuum leak comeing from to see if it affected the idle and i had no issues what so ever so im going to rule out the vacuum leak idea.

[evildky]

sounds like the air regulator is stuck open

[z32pilot62]

Okay, so I think your theory is correct because when I pinch off the line going from the air regulator to the intake pipe the idle goes down just like it should and I can hear it sounds like there is a massive amount of vacuum on that line and it collapses the hose when I do that as well. Does this sound like you found the problem?

[z32pilot62]

Well took a leap of faith and pulled the air regulator and took it appart to find that the pin that holds the baffle had come out of the housing and was letting the baffle sit with about half the hole uncovered. Put the pin back in the hole with a dab of jb and ensured that it still worked properly when dry and she works perfect now! Rock solid idle at 700, the wipers have stopped having a mind of their own but now the final 2 issues I need to address are with the door indicator light and the dash lights. The door indicator light stays about half on with everything shut but turns on full bright when you open a door. What could this be? The dash lights every time you turn the car completely off and then turn it back on completely, the dash lights will be at full brightness when you turn the headlights on. If you dont start the car though it does not do it just when you start the car it does it.

[evildky]

told ya so

[z32pilot62]

told ya so