Have a 99 civic ex 5 speed.
Replaced the iac 5 times with 3 used and 2 new.
And the cel keeps popping up for iac.
I can drive all day with no issues.turn the car off .then drive it again until I come
to a stoplight ot stop sign.then light comes on and it stars idling bad.

If anyone has any ideas please help

 

swapped out the ecu and still doing the same thing

 

check for vacuum leaks on the intake manifold and hoses

 

blk crx,


Inspect the Vacuum bulk hose for any vacuum leaks. It's shown as ref # 14 in the diagram below:


*diagram courtesy of hondapartsnow.com; all rights reserved

 

check map sensor/tps/fitv

 

my 2000 si does this too, but when i try to take off from a light and push the gas a little the motor starts pulsing from about 1600-1800. any ideas of what this could be?

 

Intake manifold gasket or vacuum leak in hose 14 in the diagram above

 

Another question.why do you guys think its #14 that's leaking?

 

Mine does it also

 

Did you bleed the cooling system for air bubbles? Jump the ECU with a paper clip and see if there are any other codes besides the one for the IAC.

BTW, I'm not sure what the possibility of getting that many problematic IACVs but I know it's possible. I bought one that was defective and once I got one that actually worked, my idling issue went away.

 

Car stopped all issues on its own now runs great and didn't really do anything but scratch my head in confusion... Weird

 

If the problem pops up again, pull the code with an OBD2 code reader and post it. The problem obviously wasn't a bad IACV.

 

a thread like that was just solved. could help you. https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/1997-civic-si-jerky-throttle-iacv-cel-2993155/

 

thanks for the link but.i've tried everything it said.i have cleared the code like 20 times this month.but i found out if i pull the backup fuse i can go longer with out the cel popping on.

and as far as the code it shows twice on a scanner. a p0505

 

Why would you wait this long to post the CEL code in this thread - title edited.

You also have not yet described the idle problem. Is it high, low, and/or surging?

 

sorry about that.

it idles at 1500 and when you give it gas on take off it starts kicking and bucking.also when you let off the gas.

 

I have the same exact issue, can you please share resolution or any updates with us?

 

Ive been dealing with this issue for months now. Ive replaced the part and still get this issue. Clear the code using a scanner, 1-2 days later it comes back up. P0505 and sometimes twice (pending). Car jerks a little when i engage the clutch, if i cruise in neutral the idle will surge from 1k-2k until the car stops. If i press the gas pedal slightly and hold it will surge pretty fast from 1k-2k. Sometimes I will get a P0420 and P0310 but thats likely due to my ebay 02 sensor readings from my exhaust. (yonaka hi flow cat. converter+cat back system exhaust). I have gotten codes P0420 and P0310 and car runs normal. Only when I get P0505 does the car jerk.

I found this site that tells you how to diagnose it, I will attempt this tonight and see how it goes.

http://www.obd-codes.com/p0505

I have yet to swap out the ECU.