IACV Problem
03-13-2011, 03:44 AM
#1
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Car Info: 1998 RS STi
IACV Problem
Throwing a code for the IACV, Does anyone have an extra one lying around?
I replaced this one about 10k miles ago
The old one the magnet in the solenoid shattered. and the valve was binding and stuff.
This one IDK whats wrong with it. I replaced about 10k miles ago from a previously failed valve.
I pulled it off tonight and when I turn the motor to the ON position the valve opens. When the in the Off position or disconnected from the harness the valve closes, but not completely. Is it suppose to close all the way? I thought it was suppose to close all the way once the motor is warmed up. I moved the valve by hand and it moves smoothly with no sticky spots.
I replaced this one about 10k miles ago
The old one the magnet in the solenoid shattered. and the valve was binding and stuff.
This one IDK whats wrong with it. I replaced about 10k miles ago from a previously failed valve.
I pulled it off tonight and when I turn the motor to the ON position the valve opens. When the in the Off position or disconnected from the harness the valve closes, but not completely. Is it suppose to close all the way? I thought it was suppose to close all the way once the motor is warmed up. I moved the valve by hand and it moves smoothly with no sticky spots.
03-14-2011, 11:20 AM
#3
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Sometimes it would jump all over the place from 1-3k rpm then the ecu would step in and do like a cyclic idle and would hover around 1.5k
On the boost gauge the vacuum jumps around. It cleared up sometimes when driving but would come back at the next stoplight or so.
On the boost gauge the vacuum jumps around. It cleared up sometimes when driving but would come back at the next stoplight or so.
03-22-2011, 11:46 AM
#5
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Problem came back yesterday, its getting pretty un-drivable.
I have a lead that it may be a bad neutral position switch. The neutral position switch controls engine idle by allowing the ECU to detect when the car is in coasting mode VS idling mode, in Idling mode the ECU must manage the idle speed by controlling the IACV ( Idle Air Control Valve ). I'm pretty sure the IACV is still good so I'm going to test the neutral position switch today to see if the ECU is reading it via tactrix cable.
I have a lead that it may be a bad neutral position switch. The neutral position switch controls engine idle by allowing the ECU to detect when the car is in coasting mode VS idling mode, in Idling mode the ECU must manage the idle speed by controlling the IACV ( Idle Air Control Valve ). I'm pretty sure the IACV is still good so I'm going to test the neutral position switch today to see if the ECU is reading it via tactrix cable.
Last edited by Deraj_53; 03-22-2011 at 12:47 PM.
03-26-2011, 02:40 AM
#6
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*Update* Still having problems with idle
The code is P0508
Replaced the IACV with a new one to no effect.
cleaned entire Throttle Body of gunk.
Reassembled and did a pressure test on intake. No bubbles from things attached, hoses etc. from intake manifold.
Checked the terminals on the harness and the power to the valve with the key on was 12v. The sensor wire was 1 volt, is that within tolerance?
The code is P0508
Replaced the IACV with a new one to no effect.
cleaned entire Throttle Body of gunk.
Reassembled and did a pressure test on intake. No bubbles from things attached, hoses etc. from intake manifold.
Checked the terminals on the harness and the power to the valve with the key on was 12v. The sensor wire was 1 volt, is that within tolerance?
03-28-2011, 10:29 PM
#9
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Car Info: 1998 RS STi
FIXED! Spent an hour with the multimeter tracing connections on ecu and harnesses, turns out it was a stressed connector on the fuse box.
Swap gremlins averted. Re-routed connector on the harness and re-did the zipties to release tension on connector and all is good.
Swap gremlins averted. Re-routed connector on the harness and re-did the zipties to release tension on connector and all is good.
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