GoldieWang

UPDATE!!! Pulled the throttle body and IAC valve. Cleaned them both with carb cleaner. New throttle body gasket, and a coolant burp. Idles as good as new.



Ok let me start with my engine is an 02 K20A2 from an RSX type S. I put the engine in a 96 civic hatch almost a year ago. It ran perfectly fine for roughly 8 months before I started to have idle problems.

No check engine light, stock ecu, stock engine, hybrid racing fuel rail and fpr, hybrid racing cai, ktuned 4-2-1 header.

The first problem I noticed was during cold starts the idle would go to 2k rpms for at least 5 mins even on a warm 75-80 degree day. Then with a warm engine the first wot pull I would do (even at a low rpm) from that point till shut down it would hunt for an idle from 1800 to 2900 sometimes 3400 rpms. When I would stop the car it would slowly find its way back down to around 1k rpm. From this point if I shut it down and restart the engine it would idle decently correctly.

At that point I found and fixed a slow coolant leak, Burped the system three times at 30 min intervals of 3k rpms on a steep incline with the rad cap removed, and replaced the TPS with a brand new unit as to which I calibrated with my multi meter. It ran perfect for a 30 min drive home.

Now the idle is still at 2k on cold start and stays at 1500 or 1900 steady at warm start up and as soon as I drive the car at any speed or any throttle position the idle starts hunting from 1500 to any given rpm under 3400 at any pace. When I stop the car the engine still hunts for an idle.

Tomorrow is my day off so I will be pulling the throttle body and cleaning out the IAC valve.

Does anyone that is familiar with this problem have any other solutions they can throw out there? Thanks for the help guys

GoldieWang

anyone?

valter

Mine had a similar issue without a swap. It was the IAC valve and from just sitting. I assume you have a K-Pro with the swap. No useful datalogs?
I just dropped in a K24A2 in the EP3 and had 0 issues.

GoldieWang

I don't have Kpro as of yet. just a stock ECU. I didn't get to clean out my IAC on my weekend cuz it rained the whole time. I bet your right about it setting for a while as I bought it from an online motor company so who knows how long it sat around.

DCFIVER

Even if cleaning it doesn't help,it is likely still at fault. With out the IAC data PID this is a guessing game,however....

GoldieWang

I just did a search for a new IAC and can pick one up for 40 bucks. I may just do that and grab a thermal throttle body gasket while I am at it.

valter

I wouldn't even try and start the engine without a KPro.

GoldieWang

right since the stock ecu is completely incapable of running the engine itself...

In all seriousness though I don't see a need to buy kpro or tune it until I have a turbo in the engine bay

valter

When you say stock ECU do you mean the one that came with the car or the one that came with the engine? Might want to clarify that...

Mine dynod at 180hp 180tq just with a test,mid pipe and the KPro.
With all the mods you have( after checking your thread) will will gain easily 20-30 hp by KPro and a tune.
Back to the point if you are running this with K20A2 ECU as it seems. Bring it to Honda and have them diagnose it. Assuming you have cleaned the IACV and burped the engine.

Miguel Munoz

Mine is having the same issue except mine only starts to hunt after engine warm-up. I can't seem to find the proven but I'm sure it's simple. Please help.

f1nal zeros

If you are having idle issues I would check the idle air control valve like others have said and also a small rubber vacuum line that runs off the manifold. If pinched or cut it will cause the idle to jump around.

Miguel Munoz

Hunting/erratic idle problem solved! I took apart my whole throttle body. Thoroughly cleaned out my idle air contol valve, fast idle valve (tightened the plastic ring around the beeswax pellet to fit snug), cleared out idle control valve and all ports leading through the carb. As soon as I turned the car on, everything sounded better. Rpms go straight back down to a perfect 715 after startup. Thanks for all the discussions and blogs! I'm returning the favor.

Run down: Symptoms would be high, car acceleration would be faster than normal when depressing gas pedal, idle became erratic after warmup or when shifting off loads. Cold weather seemed to intensify problems. There you have it. Clean out everything. Simple process

GoldieWang

I finally had a nice warm dry day off work and cleaned the entire throttle body and iac valve really well. It was gunked up something stupid. Burped the coolant and took it out for a drive, runs perfect now just like the day I finished the swap. I believe my CAI was sucking in some rain water even though it was behind the rad and probably a foot from the ground. So I ran the CAI over the trans. Should do better now.


Valter, when I said stock ecu I was implying the stock k20a2 ECU. As far as the Kpro goes I really like it and want it for diagnostics purposes, I just don't want to trailer the car to a tuner and pay for a dyno tune only to do it again a year from now when I complete the turbo setup.

Miguel Munoz

Awesome At least you had a warm day! I was freezing my *** off trying to clean out my manifold!

GoldieWang

My issues were identical and on a warm day it ran perfect but cold days was a no go. It was so aggravating/embarrassing to drive.

GoldieWang

Your right though, that Kpro is no joke man. My buddy has an identical hatch with a k20a2, dc headers, CAI, eagle fuel rail, and Kpro. He can easily pull 3-4 lengths from a dig if not more.

valter

Good to hear it was a simple clean to fix it. With the K20A2 i doubt you will need to bring it to a tuner. Hondata has so many cals that are already on the KPRO. The other option get the reflash until you boost. I had it and its awesome also. The best part about it is they discount the KPRO for the cost of the reflash when you upgrade to KPRO. Happy "VTECing".

ep3_skylar

I am having the same problems and done the same thing you have done but am still having same issues.

Miguel Munoz

If your's is still chugging then I would assess the whole firing process from start to finish. Starting with fuel pump, fuel filter. O2 sensor. Are you using a motor from a JDM shop? They have been known to have sensors that can cause problems for motor swaps.What kind of spark plugs are you using? Make sure it's Ngk. Set timing? Is the dizzy old? Vacuum leaks? Spray some throttle body cleaner around the intake. Concentrate on nipples and gaskets. Double check the fast idle valve. That one usually solves idle ramping.

GoldieWang

If none of what Miguel says helps then it is possible that you have a bad IAC Valve. Take mine for example I cleaned it up and reinstalled but I know its not going to last very long because it was catching due to rust on the outside of the shaft (at the magnet). I cleaned it all up and got it moving freely but I am sure the rust will be back and cause it to hang up again. Honestly its beginning to slowly get some symptoms back like a high idle if I drive without fully warming the engine. its no biggie though just gotta make it through Christmas!