I'm having problems with idle on my B16A and now it has gotten bad enough to cause the engine to die regularly. This has happened after having a major rebuild (i.e. pistons, headwork, cams, IM, intake, etc.). I have replaced the IAC valve and have cleaned and adjusted the throttle body, and still have this issue.

My question is this: Could the Fast Idle Thermo valve be causing this issue, even after the car has warmed up? Or could there be something else?

I have taken the car to Dyno Spot Racing for tuning and to see if they can resolve this issue, but their opinion is that there is something mechanical that is not correct. Since I have installed a larger intake manifold (Skunk) could there be a problem with manifold pressure using the B16 throttle body and sensors?

I'm at the end of my rope here, and if I can't get this fixed the car gets garaged indefinately.

 

Remove the FIV and plug the hole. See if that works.

Please tell me you adjusted the trottle body already.

 

Sorry... I can't tell you I have adjusted the trottle body. I am not the one that has been doing the work on my car (outside of replace the IAC), so I only know as much as I have been told. Explain what you mean by adjustment and maybe I can tell you if it has been done.

 

Disconnect IACV.....and run car without it.
There is a screw in the top of the trottle body that adjusts the plates position....turn screw and see if RPMS rise or the car keeps from stalling after start up. If so, adjust until 750 RPM. Then shut car down, clear ECU codes, reconnect the IACV and start car.....let it run until the coolant fan turns on so the ECU can relearn the IACV and the trottle.


[Modified by Spade, 3:13 PM 8/9/2002]

 

You know... it probably needs to be done again. With all that has been done to it recently I know it has been done a couple times, but who knows...

 

All you need is pliers and a flat head screw driver.
pliers to pull ECU fuse.

 

why not just disconnect the battery cable for 15 minutes or so? easier than pulling a fuse.

 

The fuse is right there too....btw, it's ten real seconds not 15 mins

Just count slowly to 10 and replace.

 

Something I forgot to mention in the beginning: The engine will die when I drop out of gear coming to a stop light... so the rpms will drop like normal, but will continue dropping until it dies. This is what usually happens, but it doesn't happen all the time. Sometimes the idle bounces around 700-900. And other times it is just fine.

Anyway... just wanted to add more info. I'll adjust the idle stuff tonight or tomorrow and report on the results.

 

Get a bucket of water and check all of your vaccum lines for leaks. although this is usually for higher idle.

 

Vacuum lines are okay... I keep checking them every time I work on the car.

So... the idle screw was messed up... turned all the way in. That's fixed now, and the problem seems to have gone away. But now I have another problem that I had in the past, before having the idle too low: Every time I drop out of gear to let the engine drop to idle, the idle bounces.
It drops to ~900 then up to ~1200, bounces like this 3-5 times and then finally calms down to ~750... and it does it every time I stop the car. It's almost like the ECU is in learning mode. But shouldn't that stop happening after a couple times?

 

[QUOTE]Remove the FIV and plug the hole. See if that works.[QUOTE]

A simpler way to test (disable) the FIV, is to:
1) disconnect the intake arm from the TB.
2) You will see two holes on the firewall side of the TB just prior to the Throttle plate. The lower one feeds the FIV. THe upper one feeds the IACV.
3) Use some duct tape and tape over the lower hole that goes to the FIV. Be sure an duse enough to get a good purchase, and don't let the tape touch the throttle plate.

Good Luck troubleshooting.