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Code P0118 and idles fast

 
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Old 10-14-2014, 02:15 PM
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Code P0118 and idles fast

I have a 2000 Prelude that was picked up at a parking authority auction so it was generally abused and not maintained very well. It has a CEL code P0118 - temperature sensor. I replaced the temperature sensor but the code will not go away. I also checked the wiring back to the ECU from the sensor and that is good although it does not seem to match the pin location on the ECU from a wiring diagram I found that is apparently not the correct one.

The engine idles very fast, I think because the ECU thinks it is always cold and has just started because of the code P0118. The temperature gauge on the dash seems to work properly so the code P0118 is somewhat of a mystery.
If I lift the mass airflow sensor out of the throttle body the idle goes down to 800 RPM where it should be but it runs very rich and I get a lot of unburned gasoline smoke in the exhaust.
I have cleaned the FITV and the EGR but can't seem to get the idle down where it belongs.
Where can I find a wiring diagram for the ECU and the engine sensors? The drivers front inner fender was missing and the wiring harness was rubbing the tire. I repaired all the damaged wires but still can't get rid of the code P0118.

Thanks for any help.
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Old 10-14-2014, 05:46 PM
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Re: Code P0118 and idles fast

Is the butterfly in the throttle body completely closed at idle? Could be a tight throttle cable or sticky liner, maybe try spraying some white lithium grease in the liner.. Also could be the throttle position sensor. Also, did you clear your codes after you replaced the temperature sensor? If not try doing that and see if it pops back up after driving it, dont think that would affect the idle though
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Old 10-14-2014, 07:52 PM
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Re: Code P0118 and idles fast

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This should help.
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...is a golden car fax kinda like a golden ticket? Sure hope willy wonka didn't put any snozberries in your motor.
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I remember my first thread, asking what a noise was when I got going 110mph.
Pretty much got flamed for driving like a jackass and was told to slow down. And I'll be damned, slowing down fixed it.

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Old 10-14-2014, 09:10 PM
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Re: Code P0118 and idles fast

the ecu sends a 5v reference and ground to the ECT and measures voltage drop across the sensor to measure coolant temperature - make sure the ecu is providing both.
+1 on clearing the code, or you could disconnect your battery. Try bleeding the coolant to make sure you don't have any air bubbles in the cooling system and check for vacuum leaks first. Also, try lightly tapping on the Idle Air Control Valve with a light weight ball peen hammer. These valves work using an internal stepper motor that move relevant to the temperature of the engine. Sometimes the valves get a little sticky and need some help moving along.





later.
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Old 10-14-2014, 09:12 PM
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Re: Code P0118 and idles fast

The butterfly is closing completely
Throttle cable is loose
Throttle position sensor is working
Cleared the code and idle stays high and the code p0118 is set again immediately
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Old 10-14-2014, 09:31 PM
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Re: Code P0118 and idles fast

All Gen. Prelude Service Manuals

All Gen. Prelude Service Manuals

All Gen. Prelude Service Manuals

All Gen. Prelude Service Manuals

All Gen. Prelude Service Manuals

All Gen. Prelude Service Manuals
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Quote:
Originally Posted by ogsmakdade View Post
welcome to site Carl
...is a golden car fax kinda like a golden ticket? Sure hope willy wonka didn't put any snozberries in your motor.
Quote:
Originally Posted by elspectro29 View Post
Only seen the first one, 15 years ago in theaters. Plan on keeping it that way. Get off my lawn.
Quote:
Originally Posted by Lindso View Post
I remember my first thread, asking what a noise was when I got going 110mph.
Pretty much got flamed for driving like a jackass and was told to slow down. And I'll be damned, slowing down fixed it.

God's Not Dead

Last edited by bykfixer; 10-14-2014 at 09:34 PM.
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Old 10-15-2014, 12:56 PM
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Re: Code P0118 and idles fast

Maybe the idle screw on top of the throttle body got messed with when the previous owner had the car.
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Old 11-03-2014, 03:11 PM
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Re: Code P0118 and idles fast

So I got the code P0188 fixed but the idle is still high (2500 RPM).
I reset the codes and ran the car until it was up to normal operating temperature. Idle never goes down - stays at 2500 RPM.
I have cleaned the FITV and EGR.
The throttle cable is loose and the butterfly is closing at idle.
Any ideas?
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Old 11-03-2014, 04:28 PM
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Re: Code P0118 and idles fast

Vacuum leak maybe, have you checked for leaks? Spray some starting fluid around you vacuum hoses, if the engine revs up you have a bad vacuum hose, but to get it to idle at 2500 it would probably be more than one..
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Old 11-03-2014, 09:49 PM
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Re: Code P0118 and idles fast

remove your intake tubing, look inside the intake, you'll see 2 holes (upper and lower), the upper goes to the IACV, the lower goes to the FITV.

Block these holes one at a time when your car has reached operating temperature, the FITV should not be sucking in any air (no vacuum) where as when you block the IACV, your car should stall within seconds. If your car's idle stabilizes when blocking the IACV, you've got a vacuum leak or may also be the intake gasket leak.

If your car is reving at 2500rpm at operating temperature, you may have more then one vacuum leak. Try unplugging the IACV plug, your car should idle really low, maybe 500-600rpm.

read this thread below:
Cleaning IACV, FITV and TB - Honda-Tech
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Old 11-11-2014, 03:46 PM
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Re: Code P0118 and idles fast

So I blocked the IACV and FITV holes in the throttle body - no change in idle for FITV, idle decreases a little when IACV blocked. I checked all the hoses in the throttle body and sprayed carb cleaner around everything that could leak vacuum. I could not find a leak. So if I unplug the IACV the idle drops to 1500, although it is idling roughly at 1500 it is more drivable than when it is idling at 2500 or 3000.
Could this be an ECU problem?
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Old 11-12-2014, 01:20 AM
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Re: Code P0118 and idles fast

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Originally Posted by Thoward73 View Post
So I blocked the IACV and FITV holes in the throttle body - no change in idle for FITV, idle decreases a little when IACV blocked. I checked all the hoses in the throttle body and sprayed carb cleaner around everything that could leak vacuum. I could not find a leak. So if I unplug the IACV the idle drops to 1500, although it is idling roughly at 1500 it is more drivable than when it is idling at 2500 or 3000.
Could this be an ECU problem?
If your revving at 1500rpm with the IACV unplugged it's got to be a vacuum leak, when I unplug my IACV connector my car revs around 500rpm (this is normal/should happen)
Try this, remove the rubber intake part, block your intake (round metal part) completely, your car should stall because it's not getting any air.

Make sure when checking idle always do it at operating temperature. (fans have cycled 2 times)

You may also want to check and make sure your tach/rpm gauge is giving you the correct rpm range.

When your checking for a vacuum leak, don't just check the ends of the hoses/where they're being plugged into, check the hoses from where they start and where they finish.
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Old 12-07-2014, 12:14 AM
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Re: Code P0118 and idles fast

So I have done everything suggested but I still can't get the idle down where it should be. The car also is almost impossible to start when it is cold out. It seems to be way too rich and when I do get it started I get a cloud of smoke of unturned fuel.
Any ideas what is wrong with this car?
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Old 12-07-2014, 10:08 AM
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Re: Code P0118 and idles fast

Did you down load a manual and check the trouble shoot section in the emissions chapter yet?
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Quote:
Originally Posted by ogsmakdade View Post
welcome to site Carl
...is a golden car fax kinda like a golden ticket? Sure hope willy wonka didn't put any snozberries in your motor.
Quote:
Originally Posted by elspectro29 View Post
Only seen the first one, 15 years ago in theaters. Plan on keeping it that way. Get off my lawn.
Quote:
Originally Posted by Lindso View Post
I remember my first thread, asking what a noise was when I got going 110mph.
Pretty much got flamed for driving like a jackass and was told to slow down. And I'll be damned, slowing down fixed it.

God's Not Dead
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