So i have 2 civic exs one auto one manual, and the manual one my daily driver, the crank key had grounded itself out. I swapped the y8 out of the the auto one and put it into the manual car along with new clutch flywheel and the manifold. Now the auto y8 had no problems no cel or anything, and now i keep getting a p0505 cel - idle air system malfunction. I had the iacv light before when i had the original motor but i cleaned it out and worked perfect.

I have flushed the coolant 10+ times to make sure everything was out because it was pretty dirty. I have cleaned the iacv out with carb cleaner probably 5 seperate times. And today i had completely soaked it in carb cleaner for like 20 minutes. My idle isnt surging like it use to but still idling at 1500. Before the cel turns on, it acts like its under load below around 3k rpms its hard to accelerate, jerks. Now it has been smoking today white smoke pretty decently. Seems almost as if its a tps issue but do not have a cel code for it. The motor that was in it before was a d15b7 y8 head mini me.
Checked for vacuum leaks, and coolant is bled correctly with no air bubbles.

Could it just be the iacv faulty itself? TPS sensor even though no code ( im going to get a multi meter tomorrow probably and test it )? Also i read that the a/c can affect the idle? My lines were disconnected and it is empty.

Any help?

 

What years are the two Civics?

 

both 98 civic ex

 

Remove the air intake system and use your finger to cover the hole leading to the IACV inside the TB. Does the idle speed drop substantially?

 

are you using the auto or manual i/m

 

He did state he replaced the manifold. OP did you use a new gasket? Have you checked all of your vacuum lines?

 

Ill take the intake off and try that finger test. But yes new gasket. And manual i m and everything on it. Doesnt seem to be any vacuum leaks. I went around with spray to make sure

 

You probably need to bleed that sucker than. Hopefully its just an air pocket.

 

Ive flushed it multiple times and bled but i guess ill do it again tonight

 

@RonJ. Yes putting me finger over the hole does drop the idle substancially dont know exactly to what as i dont have another person to look. Has quitw a bit of suction

 

Try this:

1) Service manual procedure for adjusting idle speed.

2) Test ECT sensor

3) Test TPS sensor

 

I thought it could ve tps but didnt throw a code for it still a possiblity? Might as well just buy one there only $11 .

 

I thought it could be tps but didnt throw a code for it still a possibly? Might as well just buy one there only $11 . when i pull the tps sensor when its running it instantly throws a code and idle is erratic. Ill test it when i get home from work

 

Yes, but test whether it's properly calibrated.

 

Ya its reading .48 closed and 4.5 WOT. No spikes or drops in between.

 

Looks fine.

 

Yesterday i went to my friends to get a new iacv and when i went to leave. It wouldnt start. Turn key to the on position all lights come on except cel. No main relay click and no fuel pump prime.
Checked and tested fuel pump, start signal, ecu, fuses. They are all good. I went and got a brand new main relay and still nothing. I tried to hook up my obd2 scanner and it wont even connect whatsoever.
After i try to start it and nothing happens the cel willl slowly dim.

Its not heat soak, it has been pretty cool. I also cleaned all the grounds

 

sounds like a possible ecu problem

 

Have you checked fuses 13 and 31 in the interior fuse box? Can you hear the fuel pump priming? I had a similar condition recently (no start, no fuel pump priming, couldn't connect to scanner) and it ended up being a poor connection/corrosion on fuse 13 I believe.

https://honda-tech.com/honda-civic-d...-here-1966666/

 

No main relay click no fuel pump. What are those fuses? I checked and teated every fuse that would prevent it from starting. All tested good.
Ill try my 97 dx ecu and see if i can atleast it get it to try to want to start.

Thanks guys

 

Has any harness been modified?

 

Maybe. It was a d15b7 bottom y8 head mini me before ,that i didnt do.

 

Click the link I posted. My fuses were good too, one just wasn't making a connection. Not saying that's your problem but I'd start there.

 

Ill try that when i get home. Stuck at work and cars at friends.

 

Ended up being combination of loose and dirty grounds. I swapped out iacv and still have the same problem.