brshqushr

Since my original post about this car, I welded the exhaust manifold for a temporary fix. Reset the codes and it ran great for couple days. Now the engine-light is on again pulling the IAC-valve code again. Checked it again for ohms(good) and with engine warm and running disconnected (according to manual)- engine speed increased. Then engine running put finger over throttle-port(according to manual)- the engine speed dropped. According to manual the IAC is good I guess. What am I missing? Do I need to check the ECM? Am going to change the ECT sensor tomorrow in case it's intermittently malfunctioning. Also, after doing those engine-running tests, when I started to rev the throttle it chugged then revved and coolant blew into the overflow. I then shut off the engine and restarted it...it acted great and ran normal again! What the heck is going on with it?

Former User

Post the OBD2 CEL code.

92ehatch

The bubbling coolant could be a head gasket or stuck thermostat or both or you could just have a bad cap.

But don't think that will throw a iacv code

Bently_Coop

Why don't you clean the IACV or have you done this?

brshqushr

Ok the OBD-code is P050. I have changed the head gasket twice in the last 3-months, the last time got the head milled .004". The IAC-valve was brand new about 7-days of running ago(or about a month and half ago). Also this is a D16Y8 engine with autotrans.. Had new radiater, thermostat, overflow, fan switch, and temp. guage sender, and knock sensor and IAC valve same time the last head gasket. Was also pulling an o2-sensor code at that time as well as the IAC code. Had a crack in the exhaust manifold which I temporarily welded and doing that cured the o2-sensor code. What else?

Former User

CEL code P0505

Describe the idle problem --> high, low, surging? Are you unable to set the idle speed to spec as detailed in the service manual?

Coolant - Did you properly bleed the cooling system?

https://honda-tech.com/honda-civic-d.../#post39830585

brshqushr

The first time I bled the coolant properly the last time maybe not. I'll do that.
The Idle speed does almost everything at different times. Usually after warm alittle it idles correct 700-800rpm. Sometimes after fully warm idles between 1100-1400.
When the throttle messes up, idle is around 1100rpm and is unadjustable down. That's when it chugs as the throttle is applied and when coolant blows. When it idles 700-800 everything works great.

When it chugs applying throttle, more throttle and it revs up quickly.

brshqushr

I installed a new ECT-sensor yesterday, cleared the codes and bled the coolant system. So far everything is working good. But usually have to run for couple days before codes are stored. Thanks for help.