Hanging idle ...
#1
Hanging idle ...
Issue came out of nowhere though.
IACV is new
TPS calibrated
No vacuum leaks (all hoses are new)
TB gasket and intake gasket like 3months old.
Coolant is bleed, actually I even bleed it again after it happened, was working fine before though.
Cold runs at 1800rpm and slowly going down to usual 800rpm +-50
Gets to operating temp, then if I slowly drive like 10kmh, press the clutch in, idle drops to around 1300, goes up to 1400 and sits there while I'm still slightly moving. I stop completely, few seconds later drops to 800rpm... It happens only at operating temp, the rest does its job as its supposed to. I have no idea where to look at, no codes, its DOHC ZC OBD0.
IACV is new
TPS calibrated
No vacuum leaks (all hoses are new)
TB gasket and intake gasket like 3months old.
Coolant is bleed, actually I even bleed it again after it happened, was working fine before though.
Cold runs at 1800rpm and slowly going down to usual 800rpm +-50
Gets to operating temp, then if I slowly drive like 10kmh, press the clutch in, idle drops to around 1300, goes up to 1400 and sits there while I'm still slightly moving. I stop completely, few seconds later drops to 800rpm... It happens only at operating temp, the rest does its job as its supposed to. I have no idea where to look at, no codes, its DOHC ZC OBD0.
#2
Re: Hanging idle ...
Unplug the IACV the idle should always drop to less than normal. If it does not, find out how the extra air is getting into the engine. The only way the engine can run fast is if it gets air. You could have a sticking throttle cable or other reason the throttle plate doesn't always close all the way when you're not pressing the gas pedal.
If unplugging the IACV causes idle to drop, that means that the ECU is commanding it to open too much. The ECT sensor could be flakey, sometimes telling the ECU that the engine is cold even though it is warmed up. This will cause idle speed to increase as it is programmed to do normally on a cold start. Ohm test the ECT or replace it.
If unplugging the IACV causes idle to drop, that means that the ECU is commanding it to open too much. The ECT sensor could be flakey, sometimes telling the ECU that the engine is cold even though it is warmed up. This will cause idle speed to increase as it is programmed to do normally on a cold start. Ohm test the ECT or replace it.
#3
Re: Hanging idle ...
Unplug the IACV the idle should always drop to less than normal. If it does not, find out how the extra air is getting into the engine. The only way the engine can run fast is if it gets air. You could have a sticking throttle cable or other reason the throttle plate doesn't always close all the way when you're not pressing the gas pedal.
If unplugging the IACV causes idle to drop, that means that the ECU is commanding it to open too much. The ECT sensor could be flakey, sometimes telling the ECU that the engine is cold even though it is warmed up. This will cause idle speed to increase as it is programmed to do normally on a cold start. Ohm test the ECT or replace it.
If unplugging the IACV causes idle to drop, that means that the ECU is commanding it to open too much. The ECT sensor could be flakey, sometimes telling the ECU that the engine is cold even though it is warmed up. This will cause idle speed to increase as it is programmed to do normally on a cold start. Ohm test the ECT or replace it.
If I unplug IACV and drive with it unplugged, rpms are lower but it doesnt hang idle ... I'm lost, is new IACV defective?
I've read online and some people call it "rolling idle problem". How do I fix it lol? Throttle mechanism is fine, I even loose the cable a bit more but it doesnt change a thing. I'm lost. Please help.
#4
Honda-Tech Member
Re: Hanging idle ...
Check your accessory belts/pulleys (Alternator, PS, AC) and make sure those are all functioning appropriately... I've seen some instances where an AC clutch won't engage/disengage properly which causes a floating idle since the engine load keeps changing.
Not honestly sure if that's what's going on here based on what you're describing, but sounds like you've checked most other aspects.
Edit: 600 posts
Not honestly sure if that's what's going on here based on what you're describing, but sounds like you've checked most other aspects.
Edit: 600 posts
#5
Re: Hanging idle ...
Check your accessory belts/pulleys (Alternator, PS, AC) and make sure those are all functioning appropriately... I've seen some instances where an AC clutch won't engage/disengage properly which causes a floating idle since the engine load keeps changing.
Not honestly sure if that's what's going on here based on what you're describing, but sounds like you've checked most other aspects.
Edit: 600 posts
Not honestly sure if that's what's going on here based on what you're describing, but sounds like you've checked most other aspects.
Edit: 600 posts
#7
Honda-Tech Member
Re: Hanging idle ...
Hanging revs when clutch depressed; but only when gear shift is in a gear - BMW M5 Forum and M6 Forums
https://www.carthrottle.com/post/rev...heads-hate-it/
These posts indicate the ECU could be to blame. Actually makes a lot of sense to me.
https://www.carthrottle.com/post/rev...heads-hate-it/
These posts indicate the ECU could be to blame. Actually makes a lot of sense to me.
Trending Topics
#8
Re: Hanging idle ...
Hanging revs when clutch depressed; but only when gear shift is in a gear - BMW M5 Forum and M6 Forums
https://www.carthrottle.com/post/rev...heads-hate-it/
These posts indicate the ECU could be to blame. Actually makes a lot of sense to me.
https://www.carthrottle.com/post/rev...heads-hate-it/
These posts indicate the ECU could be to blame. Actually makes a lot of sense to me.
#10
Re: Hanging idle ...
I dont see how that could cause hanging idle or even raise in idle ... Nonetheless, it was as I first thought, TPS ... When I would release throttle, mechanically it would close however readings on TPS were at 0.90volts, and after few seconds it would drop to 0,48volts however it had weird spike in voltage as well. Took off of my buddys civic, worked like a charm.
#11
Re: Hanging idle ...
I dont see how that could cause hanging idle or even raise in idle ... Nonetheless, it was as I first thought, TPS ... When I would release throttle, mechanically it would close however readings on TPS were at 0.90volts, and after few seconds it would drop to 0,48volts however it had weird spike in voltage as well. Took off of my buddys civic, worked like a charm.
#14
Re: Hanging idle ...
I've gone through 3 IACVs, 3 TPS sensors, ECT sensor, and 2 MAP sensors. Still ***** and runs by itself after warming up.
#15
Re: Hanging idle ...
Have you checked that it is not just the throttle cable sticking? Engine warmed up but not running, have someone press and release the gas pedal while you check that the throttle lever goes all the way back to the stop and the TPS back to 0.4 volts every time.
#16
Re: Hanging idle ...
If I remember I unplugged IACV and drove around, no issues. And no IACV is new, something somewhere is telling it to be full open I believe. New TPS, new MAP, new ECT sensor. I ran out of sensors to replace haha. Anyones input is appreciated, cant drive it like this, I let of gas pedal and its still moving forward lol.
Edit : Again doing this only when warm.
#18
Honda-Tech Member
Join Date: Apr 2001
Location: Los Angeles, CA
Posts: 1,059
Likes: 0
Received 0 Likes
on
0 Posts
Re: Hanging idle ...
after 3 years, did you fix the hanging idle problem? What was the culprit? I'm having the same problem as you describe, and I've already replaced one IACV.
#19
Thread
Thread Starter
Forum
Replies
Last Post
96hatchBoy
Acura Integra
3
09-18-2012 03:45 AM
h-o-n-d-a
Honda Civic / Del Sol (1992 - 2000)
2
08-03-2009 05:15 PM
QuickStyle
Honda CRX / EF Civic (1988 - 1991)
3
06-30-2007 02:01 PM