Here's my set-up:

'94 Accord EX w/ a '94 -'95 JDM H22a swap. Only engine mods are the following: AEM CAI, Greddy header, Thermal Cat-back.

Problem: Damn idle surges, bounces, you name it. It goes from 1K rpm to 1500 rpm and back and forth (and 1500 rpm to 2K rpm when cold).

What I have replaced thus far with NEW parts from dealer: Idle Air Control Valve, Fast Idle Thermal Valve, and Thermostat.

I have no check engine lights (even with service connector jumped - engine light just stays on constant).

I have no vacuum leaks to speak of as I have checked every single one (both physically and with carb cleaner). And they are plumbed correctly except for the EGR system (and EVAP canister - Accords have 2 vacuum lines on the canister and preludes have 3) which I found out today. I have a couple of pics available to look at. As you can see the EGR vaccum valve is not plumbed inline with the EGR solenoid.


The EGR solenoid is plumbed correctly to the EGR valve on the intake manifold.
When I try and set the base idle with the IACV disconnected, it will idle like a dream! After I re-set the ECU and plug in the IACV sensor, it will still idle like a dream even when the radiator fans come on, when I put on my headlights, and even with my stereo bumpin'. The idle will still surge though if I go and take my car for a test run.

(sorry for the long post) but my question is this - Does the EGR vaccum valve have an effect on the idle if it is not hooked up? Also, what about the EVAP canister vacuum lines? Do I need to replace this with a Prelude one and route vacuum lines accordingly?

Please help! I am very frustrated with the piece of metal parked in my driveway!!

Any help you guys (and gals) can provide will be greatly appreciated!!

 

Wow, 40 views and nobody has anything to say? Have I stumped Honda-tech?

 

Have you changed any of your im gaskets? Just a thought, my friend had the same problem on his f22, just replaced the gasket inbetween the runners and upper portion of the im. No more problems.

 

mines been doing it for about 2 1/2 years now. it jumps for a while, and then sometimes its fine for a few months. i just dont care anymore. sorry i cant help, cause i treid all your solutions too.

 

did you swap pins a6 and a11? those are the o2 sensor and EGR pins. they are different than any other OBDI honda ECU.

 

have you mess with your Throttle Position Sensor (TPS) at all...? if so...you have to adjust the voltage on it...it's .45-.50 volt at idle and about 4.5 i think on full throttle...i hope that helps...cuz when i did my swap...and i was messing with the TPS it gave me that surge idle...i might not be your problem...but it's one of the thing that can cause it to surge...

 

even after when you stop at a stoplight?

 

i say you should bleed the coolant. there may be air in the system causing the eratic idle.

 

update fuel pump??

please dont say your running the accord one.. that has fixed several problem like this from the ppl i know


thats my next step

 

Thanks for all the replies.
TPS voltage is dead on what it should be (i.e. .5v at idle and 4.5v a WOT).
Coolant has been bled several times.

UPDATE: I can get it to idle 85 - 90% of the time during the day (even when driving and coming to a complete stop). The idle will surge once again when I drive at night because I had alot of electrical stuff on, headlights, rear defogger, blower and A/C. Once I turn most of the stuff off, it will idle right once again.

I'm thinking it my be my voltage regulator?!?
Any thoughts out there?
Thanks again for helping me troubleshoot

 

I had this problem for about 6 months. replaced 2 IACVs, radiator, checked TPS reading, and did all the things listed above. swapped out my jdm p13 with a chipped ecu one day and it fixed it. my guess is a bad ecu. dunno how but that was the problem.

 

i have an 90 accord with an f22a and it did the same thing until I changed my pcv only 1.76 from autozone.

 

ok, found out I had a bad PCV valve - replaced it and turned my idle screw 720 degrees clockwise = NO MORE SURGING IDLE!!!!!!! I fixed it - FINALLY!!!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Hondaaccordvtec &raquo;</TD></TR><TR><TD CLASS="quote">ok, found out I had a bad PCV valve - replaced it and turned my idle screw 720 degrees clockwise = NO MORE SURGING IDLE!!!!!!! I fixed it - FINALLY!!! </TD></TR></TABLE>

where is the PCV? i mean for a buck at pep boys. ill look into this:

can you get a pic or diagram on what i am changing?

 

that could happen if you don't plug in the ecu connectors all the way.. you try to check for a CEL code.. but the light stays constant.. and will not run right.. obviously

 

You might wanna check the Throttle Postion Screw, its on the top of the TB.
Screw it to the right to close it, left to open. When the car is surging turn the screw to the right slowly until the surging stops.

My 0.2