Layla.7

My 01 prelude had this issue about 8 months ago.. I cleaned the TB really good and it stopped. It just started back again yesterday (while leaving the ECHM >:0 ) Anyways, since then I've done the following...

1. Checked all vac hoses (one actually had a slight hole right at the end where it meets the TB, so I just cut off the slack, and put it back on) Started the car, same problem.

2. Car was low on coolant, so I added more, burped it. Still same issue.

3. Cleaned the Tb, and removed the IACV to clean it as well.

The code is reading my IACV, but they're expensive, and I'm not sure how accurate "AutoZone's" readers are. I've had issues before that their codes have been completely wrong. I already ordered a new IACV, but it won't be here until Tuesday, so I want to make sure I try everything else possible before I pick it up..

Are there any other steps I should take? Did any of you have the code pop up, then be able to fix it?

BTW. Symptoms.

1. When starting car, idles low at about 200rpm (for about 5 secs) Then will jump back up to just about 1000.
2. When AC is on, car runs f*ng terrible. (just turned it on to see what it would do, since then, have kept it off) I tried turning it on again when the car was in N, and I was parked, and I thought it was going to shut off on me, RPMs dropped to like 100.
3. When in 1st or 2nd gear (normally between 1200 and 2000RPM) The car jerks like a 16year old who just learned to drive a stick shift. It ALSO jerks hard with just the slightest release from gas pedal (high or low rpms)
4. If I'm parked, with the car in N, and rev the engine, it will bobble up and down (womp womp womp womp) Once, I pass 3000 rpms, the needle will shoot up quickly with no hesitation at all.

Basically, the car is drivable, but it's annoying as hell and quite frankly. Embarrassing. The only way I can make it not be as bad (but still there) is by riding the clutch. Soon I'm gonna need a new one if I can't fix the problem.

Any suggestions? Similar stories?

1GPlusSH

you may have a combination of things causing your issue. since the car has a replaced motor, make sure your connections are good. i'd start with your alternator. how tight are your belts? you can get them TOO tight. the cat can cause the car to jerk when letting off a little on the gas.

what ecu do you have? have any piggyback unit? have any electrical mods to the car...underglows, aftermarket alarm, anything?

cetcivic

tps calibration?

Layla.7

Update... I put in someone elses IACV today and am having the same problem... The code read the same. IACV circut. So I came to the conclusion, either the wire is bad, or the ECU is bad. I unbolted the ECU and disconnected the 32 pin connector and tested the same wire on the harness with a circuit checker.. So here's my new question..

If I connected the checker to that pin in the harness (not connected to ecu) and the light DIDN'T come on, that means that the wire's bad, not the ECU, correct?

For some reason I can't wrap my head around it haha =( I assume if there's no power going through the harness, when it's not connected to the ecu, that it's the wire, not the computer.. All the other wires lit up, but I'm still not sure either way.

Maybe I'm just assuming this because that's what I want to be the case. hahaha.

bigtymer2306

well ive been troubleshooting the exact same problem... and today i took the iacv off cause it was making weird noises.. tried to reset my idle by running without the iacv vavle connected electrically.. and drove it without resetting my code for the iacv (since i had it disconnected) and it drove how you described.. jerked around and below 1500.. at 2500 like hesitated and bounced and above that was fine.. when i got out and reset the code... turned it back on and it drove like it was driving... lol im not going to say normal cause im still having trouble with the a/c and low idle etc... but jerking and the hesistating and stuff stopped... try switching your iacv again and disconnect the battery to reset the code and then try it.. good luck lemme know what happens cause i been pullin my hair out tryin to figure out this a/c thing.. hot here in florida and im %50 sure its my iacv ;-)

Milliron

Wow. I am having the same thing also. I have cleaned everything that Layla has talked about. I found that I have a small exhaust leak just before my o2 sensor (the 3 bolt gasket from the headers to down pipe) I think it's causing the o2 sensor to read incorrectly and causing some of my issues. Not sure if you two have any exhaust problems but I'm thinking that may be an issue also. I'm putting in a new o2 sensor for good measure. Good luck.

gheezy

ok ok I had the same problem but i fixed mine. ECU threw the same code now my bb6 runs like new after fixing it. Regardless of what some people may tell you on forums, our 97+ preludes have Fast Intake Thermo Valves. You must remove it from the bottom of your throttlebody, clean it with break cleaner and screw the white plunger screw back in tight, but then turn it back out a quarter turn. Trust me this fixed mine as i did it YESTERDAY. Reset the ECU when you're done and problem solve. Look up the Fast Idle Thermo Valve fix and you'll fix it, takes 30 mins at most. let me know as this is the most common honda idling problem.

typemismatch

4Gs have the FITV too

gheezy

yeah i know, it's just some will tell you that hondas that are 97 and newer won't have the FITV, which is often underlooked at compared to the iacv.

typemismatch

Another thing that people seem to have trouble with is a dirty EGR and intake manifold passages.

1GPlusSH

FITV isn't her problem. Some parts are similar, but it's not the FITV

gheezy

if it's not the FITV, what's the part called under the throttle body? that's basically what i messed with to fix mine. I have a swapped motor and it had the exact same problems as Layla's. Mines running fine now.

yroachy

https://honda-tech.com/forums/showth...h22+idle+surge

check continuity of the iacv wire with a multimeter, unplug connector from the ecu, connect one multimeter lead to the proper connector pin (@ecu), and connect the other lead to the iacv connector, if resistance is low wire is good, if resistance is high, or out of range on the multimeter, then your wire is bad.

1GPlusSH

the FITV may have fixed your issue, but my experience with them isn't what Layla is talking about. it's close, but they aren't the same symptoms.

i hope i'm wrong, and she can get that fixed to cure her problem.

gheezy

no knock against you but i did the exact step by step as layla, to diagnose, then i finally did the fitv fix and it solved it. I went to autozone to get my CEL read and it was the same "iacv malfunction". I'm with you though, as long as she can fix it for free or little cost, more power to her whatever the fix is.

Layla.7

You guys are great. I haven't been around my computer the last few days, so I'm just now seeing all the responses...

I was driving down the road last week and it finally hit me, I realized that the jerking and surging rpms always seemed to happen at the same spot on the gas pedal (1st I was thinking it was the sticky spot on the clutch haaha) Anyways, It didn't matter if I was in 5th gear, or 1st gear, it was always at the same spot, so I replaced the TPS.

Here's the catch, After I replaced it, it stopped jerking around and acting crazy, however, I had a new problem... ONLY after the car was warmed up and the AC is OFF, idle jumps. If I'm sitting at a stoplight and it starts to idle funny, I just turn on the AC so it goes away hahaha. That got annoying after a few days and then last night, my car started jerking around and going all crazy again... SO, I took the 1st TPS back to CarQuest and they replaced it... Popped the new one on, jerking is gone, but still have this stupid idle issue.

I never went anymore into checking the wires and stuff for the IACV since I put the new TPS in, but maybe I should revisit that.

The code for the IACV went off for a little while, now it's back on.. BUT, my ECU was for the old H22, not the JDM H22a I have now, could that be shooting me wrong codes?

1GPlusSH

i'd pull your iacv and see if you need to replace the gaskets. i would also check your fitv since NOW that sounds like your issue.

gheezy

i sent you a PM before, i had the same problem, CEL was on for IACV so all i did was look up the idle surging thread. They have a great one on preludezone if you search, removed the FITV from below the throttlebody and screwed back in the white plunger screw almost tight but not completely tight. Reset my ecu and problem solved. teh FITV is almost always the main culprit in idle surging.

Layla.7

Now now more idle issues, but the same jerking problem at low rpms when throttle is opened =( ITS DRIVING ME NUTS!! I've put in two new TPS's. They both worked for a little, then the same problem arose.. Do you think CarQuest parts just suck butt? When I open the throttle from under the hood, I hear a puff noise right around the throttle body, but I sprayed carb cleaner everywhereeee and I don't hear the idle change, so it sounds like a leak, but doesn't respond to the cleaner like a leak. MAh X(

1GPlusSH

I would think that the TPS isn't your problem if 3 different ones gave you no results

1GPlusSH

have you even checked your fitv?

jkoni426

uh you know you have to calibrate the tps right? you can't just throw it on there...

should be .5v closed throttle, 4.5v wot

and I agree with checking the fitv also...

Layla.7

Yes. I calibrated them. They did work for a little, but then fell out of calibration (which I've read means they're bad) I checked the fitv yesterday too. Plunger is where it should be. I put another TPS in today (from carquest) Car's running fine for now.. My friend gave me a OEM TPS tonight, so I'll probably just end up putting that one on tomorrow so I don't run into the same problem again.

mherkamp

TPS has slotted holes for adjustment, right? Make sure the screws to hold it on are not loosening and allowing the TPS to come out of adjustment. Chances of having 3 sensors bad, 2 brand new is kinda slim, but not impossible.
GL
Mike

Layla.7

I still haven't figured out the problem.. I put the OEM tps on, and nothing has changed. Sorry I can't help anyone who's having the same problem. Gonna try someone else's whole throttle body to try to narrow down the issue.