89 civic idles too fast
#1
89 civic idles too fast
Here are the car specs...
89 civic 1.5, dual point fuel injection , auto trans.
problem...
idles at around 1250 rpm even when fully warmed up ( in park ) place it in gear and idle drops to 1000 rpm idle isn't fluctuating just too high. the check engine light is not on ( it does work ) and no codes flash from the ecu
what I have done so far...
cleaned throttle body , checked vacuum hoses , sprayed around throttle body , intake manifold and any other areas looking for vacuum leaks , replaced iacv , topped off and bleed cooling system , changed oil( needed it)
side note.. after oil change the idle while in park dropped to 1000 from 1250 but only stayed there for a few minutes then back up to 1250. don't think this car has a fitv valve ( sp? ) so... with all this in mind any other things to check? hate to tap out and take it to a shop so any help will be greatly appreciated.
Thank you from a newbie.
89 civic 1.5, dual point fuel injection , auto trans.
problem...
idles at around 1250 rpm even when fully warmed up ( in park ) place it in gear and idle drops to 1000 rpm idle isn't fluctuating just too high. the check engine light is not on ( it does work ) and no codes flash from the ecu
what I have done so far...
cleaned throttle body , checked vacuum hoses , sprayed around throttle body , intake manifold and any other areas looking for vacuum leaks , replaced iacv , topped off and bleed cooling system , changed oil( needed it)
side note.. after oil change the idle while in park dropped to 1000 from 1250 but only stayed there for a few minutes then back up to 1250. don't think this car has a fitv valve ( sp? ) so... with all this in mind any other things to check? hate to tap out and take it to a shop so any help will be greatly appreciated.
Thank you from a newbie.
#4
Have not changed the pcv , throttle plate appears to be shut all the way at idle speed. the throttle cable has deflection. question... is there a learning process that the ecu has to go through after replacing the iacv to return to normal idle( providing the iacv was the only problem ) have yet to drive the car since doing this work only let it idle.
#5
I run the lucas injector cleaner every 6000 miles ( just added a bottle with this oil change )
#6
Pinch off the hose that goes from the side of the air box to the IACV to make sure the IACV is closing fully. When idling above specified rpm, the IACV should be closed fully and no air flowing through that hose. Also disconnecting the wires to the IACV should make no difference.
I think on the DPFIs it is legit to adjust the throttle plate stop screw to set up idle but before touching anything there, obtain and read the service manual.
I think on the DPFIs it is legit to adjust the throttle plate stop screw to set up idle but before touching anything there, obtain and read the service manual.
#7
Pinch off the hose that goes from the side of the air box to the IACV to make sure the IACV is closing fully. When idling above specified rpm, the IACV should be closed fully and no air flowing through that hose. Also disconnecting the wires to the IACV should make no difference.
I think on the DPFIs it is legit to adjust the throttle plate stop screw to set up idle but before touching anything there, obtain and read the service manual.
I think on the DPFIs it is legit to adjust the throttle plate stop screw to set up idle but before touching anything there, obtain and read the service manual.
#8
Having it slow down when you disconnect the IACV wire means that the ECU is in command of the idle speed like it should be. It may be too fast because the ECU is getting an incorrect reading from the ECT (coolant temperature) sensor. While the ECU thinks that the engine is cold, it will make it idle fast.
Or the idle is normal, and your tach reads fast. Don't trust dash tachs to set up idle speed.
Or the idle is normal, and your tach reads fast. Don't trust dash tachs to set up idle speed.
#9
Having it slow down when you disconnect the IACV wire means that the ECU is in command of the idle speed like it should be. It may be too fast because the ECU is getting an incorrect reading from the ECT (coolant temperature) sensor. While the ECU thinks that the engine is cold, it will make it idle fast.
Or the idle is normal, and your tach reads fast. Don't trust dash tachs to set up idle speed.
Or the idle is normal, and your tach reads fast. Don't trust dash tachs to set up idle speed.
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jasonknight
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03-25-2007 09:12 PM