Rob02Civic

Hey guys what's up... I have a 98 civic ex coupe. I live in AZ and its super hot right now, the other day I blew a hole in my heater bypass hose. I replaced the bypass hose and the car was running fine. Then for good measures yesterday I went ahead and changed all of the hoses, or atleast most of them. The two main radiator hoses. The heater bypass, and the two heater hoses. I didn't change the small hoses going from the iac valve tho. I refilled the system with coolant and bled all of the air out with the front jacked up. Everything seemed to be fine. Then when I put the car down and started to drive it was making a slight humming noise and the check engine light came on. Now the engine light is still on and the car has an off idle. It still runs and drives fine, its not overheating or anything and all of the new hoses seem to be working good, no leaks or anything. I got the code scanned and it came up and p0505 code which is for the iac valve. Ive never had an issue with the iac so I don't think its bad or dirty, I think I got an air pocket in the iac motor some how... Any ideas out there???

ezone

Tap on the IAC valve, it might be stuck.

Rob02Civic

Hey Ezone thanks for getting back to me man, you always help out a lot. So when I got home I started up the civic and its still doing the same thing. Using a screwdriver I started tapping on the IACV a bit, trying to get it to pop if its stuck. I gave it a good amount of taps probly 50-100 trying to see if it would change the idle but nothing happened. So I shut off the car, took off my intake and put it back on making sure everything was snug and connected. Then I checked all of the connections and little hoses around the IACV and the manifold. Everything seems solid. Its making this slight whistling noise while its idleing. When I hit the throttle it revs up good, but when I let off the rpms drop low then come up a little bit and stableize. Then I put my coolant funnel back on and reburped the system revving the throttle to 2500 rpms and I let the fans come on for two cycles. But still the idle is still doing it and the check engine light is still on. I think I have some gremlins in my Civic!

ezone

Cruise vacuum hose came off the manifold? Vacuum leak? Listen where the whistle comes from, use a length of tubing at your ear as a stethoscope and probe around the intake area.

Remove intake tube and plug the ports in the throttle body with your fingers, see if the fast idle rpm drops a bunch.

dbbiker

Hey Rob, it's been awhile but I am having exact same issues on a 97 Civic after a radiator and hoses change out.
Did you ever get the issue resolved?
Thanks, man
dbbiker

drhawkinz

Just had a similar issue with my car. If you drive it up on ramps, run the car with the thermostat set to hot until it burps out bubbles. Then top it back off.