TwinTurbo.NET: Nissan 300ZX forum - I just went through this erratic idle issue. Your idle is
People Seeking Info
 
   


     
Subject I just went through this erratic idle issue. Your idle is
     
Posted by 300NASeattle on July 10, 2018 at 11:20 PM
  This message has been viewed 65 times.
     
In Reply To Erratic idle speed help request posted by jeff1954 on July 09, 2018 at 09:24 PM
     
Message higher than mine was though and that is a pretty big vacuum leak to get to 1800.

I had 4 different vacuum leak locations.

1. Passenger side PCV intake cover hose was cracked on the bottom.
2. Fuel rail to lower intake isolators were allowing air past.
3. Drivers side throttle body butterfly was not fully closed at the factory stop.
4. The IAA to air regulator hose was allowing some air between the house and the flared hose on the IAA side.

Even with all those places it would idle at 1100 sometimes.

The first place to check is the air regulator. Remove the hose going to the balance tube from the air regulator and cover it with a heavy plastic bag or a criss cross of electrical tape and then put the house back. This will block any air going through the regulator.

If you have a compressor you should get the intake up to 5 psi and listen for leaks. If not then grab a spray bottle and mist around all of the usual places and listen for the water getting sucked in. The idle will drop when the water finds the vacuum leak as well.

There are parts in the FAQ that go over all the usual suspects and how to check them. Don't expect that there will be only one place that had a vacuum leak. Find the first and then keep looking

     
Follow Ups  
     
Post a
Followup

You cannot reply to this message because you are not logged in.