rpms bounce from 1k to 2k constant

DAGAME

04-03-2005, 10:05 PM

my rpms keep jumping from 1 grand to 2 grand at idle i think its the iac valve but i just replaced it last january, im getting new one this week, but if thats not the problem its probably the ecm so probably means getting a new ecu for my 98 civic ex, does anyone know where i can purchase one other then from honda or is there any aftermarket obd2 ecu's that work for my car that will add performance such as higher rev limiter and sooner vtec engage.

But im assuming that the only way for that to work is stock ecu with hondata or apex vtec controller? Right?

kris

04-03-2005, 10:45 PM

Look under your throttle body. There should be what is called the IAC (Idle Air Control) valve.
http://www.we-todd-did-racing.com/wetoddimage.wtdr/wODU4NDcxNnM0MTNkZmQzMXk1NDE%3D.jpg

You can take that apart, clean it, and re-tighten the plunger type piece in it. That should help solve your surge, if it is the type of surge I am thinking about.

superbluecivicsi

04-04-2005, 01:09 AM

search idle air control valve and IACV. theres alot of threads that cover it in depth and detailed.

DAGAME

04-07-2005, 12:45 AM

well replaced the iacv yet again and my car idled normal for like 10 mins and did the same shit again, the throttle body and intake manifold have been cleaned and there are no vaccum leaks, how the fuck do i fix this problem? Does this sound like an ecu problem? btw my ecu code is p0505 if that helps.

kris

04-07-2005, 01:26 AM

http://www.we-todd-did-racing.com/wetoddimage.wtdr/i=wODYzNjAzNnM0MTNkZmQzMXk1NDE%3D
http://www.we-todd-did-racing.com/wetoddimage.wtdr/i=wODYzNjA0NnM0MTNkZmQzMXk1NDE%3D

The scan tool indicates Diagnostic Trouble Code (DTC) P0505: Idle control system malfunction.

NOTE: If DTC P1508 or P1509 is stored at the same time as DTC P0505, troubleshoot DTC P1508 or P1509 first, then recheck for DTC P0505.

Possible Cause

IAC valve mechanical malfunction
Throttle body clogged port, improper adjustment
Intake manifold gasket leakage
Intake air hose loose leakage
Vacuum leak
ECT sensor incorrect output
Throttle Position sensor incorrect output*1 *1 '96 models only.

Did you replace the IAC with a brand new one, or a new (used) one?

DAGAME

04-07-2005, 01:39 AM

bought a new one from honda back january, and just replaced it with another new one from honda yesterday and still have fucked up idle and engines runs like crap.

DAGAME

04-10-2005, 05:22 PM

now whent he idle fucks up it idles at 1,500 - 1,700 and bounces between those 2 numbers rapidly, and when u barely press on the gas the engine stutters rapidly. Also when im driving and put in neutral at a stop light it will drop to 1,000 then go back up to 1,500 and do that about 10 times and stay at 1,500. Thought it might be the map sensor, but with the used motor i bought it was automatic motor so we used my old intake manifold and throttle body which i had the problem with before...any way the throttle body with the motor i got had map sensor on it and tried using that one but still didnt solve anything, please if anyone knows how to fix this please let me know be suffering from this idle shit for 8 months = /

superbluecivicsi

04-10-2005, 06:57 PM

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