View Full Version : KA24DET High Idle

07-25-2008, 10:30 AM
First, the specs.

Rebuilt KA24DE, 8.8:1 Arias pistons, emissions removed, T25 turbo (7 PSI/0.48 bar), SSAC turbo manifold, Megan Racing turbo elbow & downpipe, XS Power FMIC, SR20 370cc injectors, Z32 N62 MAF, EFI Specialists "Redline" ECU, APEXi SAFC, Nology Hotwires, Timing set @ 15.2 BTDC (retarded 1 degree per 0.1 bar).

My car idles really high.

Steps Taken to Fix:
The water temp sensor is new and working correctly. I replaced IACV and IACV Air Regulator (no change), and the idle adjustment screw is all the way in. The TPS is putting out the right amount of volts and is reading correctly on my AFC. I checked for vacuum leaks using that homemade leak detector and an air compressor (no leaks). And it's not the timing, so at this point I am kinda stumped.

History of Problem:
When I had the stock KA MAF it would idle around 1500 on startup and around 1800 after warmed up and would fluctuate a lot. After switching to the Z32 it now idles at 1000 on startup and between 1200 and 1500 after driving for a bit and doesn't fluctuate as much.

Visual Symptoms:
When the idle fluctuates, so does the needle on my boost gauge. Pressure increases when the idle lowers, and decreases as the idle increases.

When I am driving and I take my foot off the gas, clutch-in, neutral, and brake the idle will rpm drops to 800 then jumps back up.

LMK what you guys think. Thanks

10-02-2008, 02:19 PM
Maybe a vuccum leak

10-02-2008, 05:23 PM
how did you set the iacv? did you dissconnect the tps sensor, and then adjust the idle? because that is what you have to do!

12-06-2008, 09:15 PM
ever fix the issue??

12-07-2008, 08:23 AM
I bet it was the AAC

12-09-2008, 11:11 PM
Check the timing, mine was jacked up when I got it.

01-31-2009, 02:46 AM
ever fix the issue??

Ditto. If so, what was the problem?

I'm having a similar problem with my non-turbo KA24DE. My idle is ~200-300 RPM too high with the adjustment screw all the way in. My timing is set to factory spec (except that it's idling at 900 instead of the "proper" 700; TPS was unplugged when it was set). Everything else otherwise feels normal on the car while driving.

I hope I'm not digging up a thread that's too old (only a little over a month and a half since the last post in it).