Sharpen047

Ok guys, having some major trouble with my civic. Just got it a few months ago with a burnt valve, replaced the head, it ran great for about 2 months.
About a week and a half ago the idle started fluctuating, it got progressively worse. Last Thursday it was idling at about 2500 rpm(I'm guessing, I don't have a tach). I decided to clean the Iacv with no change. It finally threw a cel, code p0505. After fiddling with it for a while I drive it to work and it threw the temp sensor code. I replaced it, it went away but the idle issue persisted. Yesterday my friend with a 98 ex and we swapped the map, and IAT with no change.
Checked for vacuum leaks with carb cleaner and didn't find any near the throttle body or the intake manifold, even checking the underside from down below with more carb cleaner.
So anything else I can try? I've also bled the coolant system, leaving radiator cap off and running with heater on full.
Thanks in advance.

crxsi1

There should be a bleeder srew somewhere near the radiator... so make sure its topped off and put the cap back on and open that bleeder srew... if you bleed it with the cap off you dont build up pressure in the system which could allow air to stay trapped in the system and could keep causing it to idle like that... hope that works

Sharpen047

Ill look in a few hours when I am off of work. But I've driven it for a few days since. No luck.
Thanks for your input

jbpnoman

The Y7 doesn't have a bleeder screw.

When you bled the system, did you have the front end on jack stands? If you don't, it won't work.

Sharpen047

I took it off the ramps before I bled it. Was on nearly level ground.

crxsi1

Really? I've never done that and have had no problems bleeding... if the car is running the pressure would build up enough to push any air up to the top... maybe not on the engine but the radiator could have a bleeder srew...

Sharpen047

i dont see one, any other ideas?

HondaPartsHero

Yeah I'll confirm you don't necessarily have to lift it up.

Sharpen047

based on that i need to check vac leaks or adjust idle.
since it idled fine before, im guessing i HAVE to have a vacuum leak.
does anyone have a vacuum line diagram?
Should i just replace the intake manifold gasket? $14
should i replace the tb gasket? $22

HondaPartsHero

Get some carb cleaner and spray around the manifold, throttle body and vacuum lines. If the idle changes when sprayed around that area most likely has a leak.

Spade

The TB and IM gaskets hardly ever are the problem.

Try the simple method first of blocking the IACV with some aluminum cut from a can and make sure that sucker isn't an issue. It was for me and I just learned the live life with it blocked off.

Sharpen047

Ok I adjusted the idle screw and it seems to idle great. But it still throws the 505 code even after I erase codes
Edit: just saw your post, I tried that but the car doesn't idle by itself when cold. I'm guessing that's what you mean by live with it?
Think the idle screw could have come loose?

Spade

Yup "live with it" I just setup my pedals and would heel-toe until the car was warm.

HondaPartsHero

Did you adjust the idle by the procedure in the FAQ?

jbpnoman

Then I guess the FSM lies in it's description of how to bleed the coolant...

When the car sits level, the IACV is ABOVE the coolant fill neck. Air seeks the highest point in a system. Without jacking up the front of the car, air can stay in the IACV, defeating the purpose of trying to bleed the system. To properly bleed the car, you need to make sure the bleed point (in this case, the fill neck) is the highest point in the system.

Sharpen047

Ill put the car on ramps and try that.
If you mean this http://i639.photobucket.com/albums/u...cture_4760.jpg
Then no, I don't have a tach I can use for the car or a honda PCM tester.
Although I did leave the IAT in and a c wasn't on.

jbpnoman

You don't need to turn on the air conditioning - it doesn't have anything to do with your coolant system. You don't need to have heat on "full blast", just having the slider all the way to hot is enough. Just make sure the filler neck on the radiator is the highest point in the system (above the motor and coolant hoses).

HondaPartsHero

From the FSM (RonJ's pics in the FAQ aren't working)

wesvailco

-lock-out ECU and check base timing, 12°±2°, bet it's off. that fixed my low idle, no codes though.

-since the ECU is showing a code for the low idle, it may be the connector since you've swapped valves/throttle bodies with no change. check for crud/cracks/obvious signs/voltage.

Sharpen047

I kept the Same intake manifold and nothing else was changed.
Why would timing become off after running fine for months? I am still looking into why its throwing a code. If I have a vacuum leak isn't that the same as adjusting the idle screw? Doesn't this rule out vacuum leak?