Idle issues *Urgent help reqd!!!*

[CivicSi]

Hi Guys,

I've got an idle problem with my car! When you start it from cold and the revs sit higher whilst the car is warming up it idles fine, but when the engine's warm and the revs drop, they drop to a very rough 400 and then eventually the engine dies! Any ideas on what the problem could be?

Engine is a D16A8 in an EH9

[TODA AU]

When did the problem start?
What was done just prior to the problem occuring?

Check engine coolant temp sensor is plugged in correctly & not loose or full of oil.
Check ignition timing.

[55EXX]

idle set too low. maybe the idle was adjusted down and the fit valve was stuck open now the fit valve is working again, new coolant flush maybe it idles too low

[nick_sixx]

if you have a carbon bonnet, or carbon intake, particles can get caught in some valve (ICA/IAC/ACI?) i cant remember what its called but yeah that generally causes idling issues similar to yours

[EuroDude]

If engine is cold and the revs are above 1500, screw in and clean the FITV valve

If the engine is completely warmed up and drops below ~750 when idle, the most likely cause is a clogged throttle body (idle air bypass valve). Another cause could be a dirty IACV filter, dirty fuel injectors, bad spark plugs/leads, vacuum leak, etc..

Dont try fixing the problem by adjusting the Idle screw, you should fix the source of the problem rather than patching up the problem, possibly resulting in performance loss and even worse idle.


Search the DIY section for "Throttle Body" and "IACV"

[nick_sixx]

^^^ i was close with IAC

[CivicSi]

If engine is cold and the revs are above 1500, screw in and clean the FITV valve

If the engine is completely warmed up and drops below ~750 when idle, the most likely cause is a clogged throttle body (idle air bypass valve). Another cause could be a dirty IACV filter, dirty fuel injectors, bad spark plugs/leads, vacuum leak, etc..

Dont try fixing the problem by adjusting the Idle screw, you should fix the source of the problem rather than patching up the problem, possibly resulting in performance loss and even worse idle.


Search the DIY section for "Throttle Body" and "IACV"

Ok, i've gone ahead and checked the IACV, checked the throttle body... both are fine...
I've cleaned the fuel injectors, replaced the rings on them and the buffer seals...
I've replaced the spark plugs
And i've taken off everything that could be leaking and put it back on with genuine Honda grey gasket sealant....
I've also tried replacing the O2 sensor, as i know the ecu runs a closed circuit on warm up before taking data from other inputs

Still having the same issue!!!!! Any ideas?

[CivicSi]

Nobody wants to put in their 2 cents?

[INTEG]

Mine was the same is it DC2 i change idle control motor behind the manifold

[CivicSi]

Already adjusted that.... don't want to just cover the problem though... want to fix it!

[INTEG]

what u mean u adjusted it ? i dont think you can? if u talking about the screw on the TB it not it

[CivicSi]

Oh, soz... the screw on the TB was what i thought you were talking about! Idle control motor, where is it ?