Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Tech Talk > Engine Tech

Engine Tech Technical discussion related to all relevant engines such as KA, SR, RB, CA, 2JZ , L24/26/28, VG, VQ, and LSx series.


Reply
 
Thread Tools Display Modes
Old 01-26-2017, 01:05 PM   #1
richierichness
 
Join Date: Oct 2015
Location: Virginia
Age: 32
Posts: 29
Trader Rating: (0)
richierichness is an unknown quantity at this point
Feedback Score: 0 reviews
RB IAC Delete or Drive by Wire?

s14 w/stock rb25 s2
q45 TB
Greddy knock off
VE tuning with Haltech Elite 2500


What are most people doing to clean up the idle on their RBs? This thing is a nightmare once the engine warms up. If I target any RPM below 1100 the idle will bounce around and eventually the engine will stall. My goal is stable idle between 700 and 900 rpm.

Steps taken so far:
-Adjusting IAC screw
-Tuning fuel via open and closed loop
-Unplugging IAC and valve
-Boost Leak Testing
-Fuel pressure is good (43 psi)
-New injectors (900 cc)
-New Battery
-New plugs gapped to .030"
-Ohms coil pack testing (hot and cold tests)
-O2 (Haltech) Wideband sensor is functioning properly (deleted oem narrowband)


Steps I have not taken yet:
-Replace Coolant Temp Sensor
-Clean IAC and valve
-Diagnostics testing for IAC,valve, or TPS (does this need to be done?)
-Clean Throttle body

Should I stop fucking with this and completely delete the IAC system?

Should I go 1 step further and do a drive by wire TB? Does anyone make a kit or parts to support drive by wire with the RB's?
richierichness is offline   Reply With Quote
Sponsored Links
Old 01-26-2017, 01:50 PM   #2
KAT-PWR
I'm always hangn wit shooters
 
KAT-PWR's Avatar
 
Join Date: Dec 2011
Location: FL
Age: 25
Posts: 2,033
Trader Rating: (11)
KAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really niceKAT-PWR is just really nice
Feedback Score: 11 reviews
Battery voltage offset issue making timing go crazy trying to idle compensate?
__________________
S13.5 KA-T Build
MRP Manufacturing
IG:240_Trav
KAT-PWR is offline   Reply With Quote
Old 01-27-2017, 02:47 PM   #3
ultimateirving
Zilvia FREAK!
 
ultimateirving's Avatar
 
Join Date: Nov 2010
Location: arizona
Age: 30
Posts: 1,485
Trader Rating: (1)
ultimateirving is an unknown quantity at this point
Feedback Score: 1 reviews
Ok first take the iacv off and clean it. These things can get gummed up and cause it to function poorly.
__________________
Sr20det - z33 trans-e85
Desert Street Scene || Dssevents.com
ultimateirving is offline   Reply With Quote
Old 02-04-2017, 03:37 PM   #4
richierichness
 
Join Date: Oct 2015
Location: Virginia
Age: 32
Posts: 29
Trader Rating: (0)
richierichness is an unknown quantity at this point
Feedback Score: 0 reviews
I've replaced the coolant temp sensor and IAC... still having issues.


Sent from my iPhone using Tapatalk
richierichness is offline   Reply With Quote
Old 02-04-2017, 05:21 PM   #5
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 35
Posts: 3,914
Trader Rating: (17)
Kingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to allKingtal0n is a name known to all
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
If I have a car giving me trouble with an idle, the first thing I do is disable the IACV completely and boost leak check the engine for pressure leaks. If it still bounces around, the next step is disable the timing control (lock the timing steady). If the engine is still having trouble, manually verify the locked timing for each cylinder using 90* timing marks to ensure each one is sparking at the right moment. Then, you are looking for combustion related issues, fuel pressure, checking spark plugs, cleaning injectors, time to start thinking about a camshaft related issue or other airflow related source that is not controlled by the computer.

Then work backwards. Once the idle is stable with a locked timing and no idle control motor, you enable the timing and tune the map for stable idle control timing. Then you add back the IACV function and tune that. The idle control motor is the icing on the cake; shouldn't need one to maintain a steady idle, it just helps raise and lower the idle for temperature, any added idle control function is a bonus feature (icing). You should not be looking at it for idle stability as a sole, primary function. That just turns it into a bandaid, the opposite of icing.
Kingtal0n is offline   Reply With Quote
Reply

Bookmarks

Tags
delete, drive by wire, iac, iacv idle control valve, rb25


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 12:19 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
vB.Sponsors
Copyright © 1998 - 2015, Zilvia.net™