MHDesigns

I know you have heard it before but I'm dead on money and don't have parts to borrow to test things so hopefully I can get some positive useful information so I can get this done right. The motor is a b18A1 with a b16a2 head and Itr pistons. My motor has a high idle(12-1300rpm) and it's surging to about 2700 consistantly. IACV is brand new and wiring reads proper voltage. I cleaned and adjusted the FITV several times with no improvement. The TPS is showing proper voltage. Proper voltage at the pcm as well for all components. Coolant is bled and new thermostat. New fuel pump as well. When I step on the gas motor seems to have full power but when I just rest my foot barely on the gas the motor surges much quicker and is only 300-400 rpm surge. I'm just not sure where to check next. This started very randomly on the way home one night. It was very sudden. Thanks in advance for any help, it will be greatly appreciated.

BryanM.

iTrader: (1)

Vacuum leaks can cause weird issues like that. Let me guess, no CEL?

MHDesigns

Well I had P0505 and P0141 I replaced 02 and I'm still getting both(any suggestions on P0141). The car hasn't hit the streets though so it hasn't had time to think really to throw a new code yet.

MHDesigns

Just threw the P0505 after letting her run a bit and then touching pedal.. Everything appears to be connected. It will idle after clearing ecu at about 1300rpm then as soon as my foot touches the pedal it gets angry and surges again and cel pops up. Do you think the tps might be crapping out? seeing as it acts funky when my foots on the pedal. The only time the throttle seems to remain at a steady level is if I bring the rpm's up to like 3200 and hold it. then it will stay right there no problem.

Davus

Grab 2-3 cans of carb cleaner and start spraying the engine bay around intake manifold, fuel injectors/rail, and the hoses (PCV, brake booster, and cruise if installed). I recently fixed a rough idle by replacing my PCV hose, it looked fine 'til I noticed the dips aren't just bends, they were cracks. I proceeded to rip it in half with my bare hands. 5 bucks later (new PCV too) my fuel economy is up, and I'm not looking like a street racer at every light.

MHDesigns

Thats what I hate about this. I have another dd and just drive this after work and at night. Now its just sitting cuzz I feel like a jerkoff sitting at the light "Bwaah""Bwaah""Bwaah""Bwaah". Ill check that out and let you guys know how it goes but the motor was built less than a year ago with new lines on everything so if anyone else has any other suggestions/experiences it would help

Former User

First check whether the throttle cable is adjusted too tightly. The cable should have 3/8" to 1/2" of freeplay.

P0505 almost surely indicates a vacuum or intake air leak. Here's how to verify. When the engine is hot, pull off the air cleaner/intake. With the engine idling, check whether covering the port in the throttle body for either the FITV or IACV reduces the idle speed.

1) If covering the FITV port eliminates the high and hunting idle speed, then the FITV is bad. Replace it.

2) If covering the IACV port reduces the idle speed and stops the hunting idle, then try to adjust the idle speed with the screw on the throttle and, if unsuccessful, then you probably need to replace the IACV.

3) If covering either the FITV or IACV port fails to change the idle speed, then you have a vacuum or intake air leak. In this case, check whether any vacuum hoses are broken, loose, or disconnected. Also check the throttle body and intake manifold gaskets.

Davus

Good luck, I'll try to watch the thread and see if I can contribute anything else. Also spray the throttlebody-intakemanifold area to check that gasket. I just hope that, if it is a leak, it's not on the under-side where it's hard to find.

Also you can make the rough idle go away (steady 3000 or so RPM) by pulling the ECT sensor plug usually, but that's a lose-win situation. Sometimes worth it though. >_>

MHDesigns

Ok were on to something here. I plugged the IACV hole and the problem surging went right away. BUT this is the third IACV to be on the car. First one was on there, then got a Brand new one because i figured thats what it was. Then it didn't work and I had charging issues with the #15 fuse going out. In this process I had parts off of the car and my dumbass roommate left the garage open and bam my parts are stolen. So I just bought a brand new IACV last night. the other one I have is Less than a month old. I don't think I have had 3, including 2 brand new, IACV's fail. Why would this be failing? Like I said Theres connectivity and proper voltage at the IACV and PCM(ECU). I'm confused.

Former User

For fuse 15 blowing, check out this TSB.

Have you tried to adjust the idle screw on the throttle body?

Given that the IACV is basically new, you should also do electrical troubleshooting of the 2-wire coolant temperature sensor (ECT) below the distributor.

MHDesigns

Why should I check the ECT? The thermostat opens, fans turn on, and dash gauge is working. Isn't this what the ECT does? not doubting just curious as to how its tied in to the system.

MHDesigns

Idle screw on TB only will raise idle. Also does the air that goes to IACV pass by TPS. If so could this be my problem?

yellowjdmcrx

dude, i had the same prob on my eg i got so tired of dicking with it so i just took a thin peice of plastic and put gasket sealer on both sides and put that between my iacv and intake and have not had a dam prob out of it since

MHDesigns

Can I just do this with throwing a cel? do you have a cel? Lol I was just thinking about that cuzz it appears to work with the hole covered up so if I made a gasket with gasket material and sealed it inbetween TB and IM I should be ok? If this will cause future problems or current problems someone please let me know.

Utzz

Only raise the idle? Not good. The air that goes to the IACV has got nothing to do with the TPS. You didn't mess with the throttle plate stop nut to change the idle, right? As in, the throttle cable attaches to the throttle rotor...and there's a stop nut that the rotor rests upon - are you messing with that one?

If the engine is warmed up (FITV should be closed at this point) and you unplug the IACV (2-wire IACV's shut down and close off their air passage) - what does the idle drop to? It should be around 500-600rpm.

Former User

Your Civic has at least three different coolant temperature sensors (ECT). (1) The 2-wire ECT switch in the thermostat housing that controls when the radiator fan turns on. (2) The 1-wire ECT sending unit under the distributor that sends the temp signal to temp gauge in the cluster. (3) The 2-wire ECT sensor under the distributor that sends temp signals to the ECU. This is the sensor that you need to troubleshoot because,, if it malfunctions it can throw the P0505 code. If this sensor sends false temp readings to the ECU, the ECU in turn will falsely tell the IACV to open and close, thereby leading to a hunting idle.

Pothole987

I hate hunting idle...
i know i had a problem with mine, have you checked to see if your coolant it filled? or air in the system?
also when you take the IaCV off do you notice if the rubber hoses have antifreeze in them? the problem i had with my old y8 was the rubber hose was plugged ( stop leak bs) someone put in there.
worth a shot.

Former User

You turned the idle adjusting screw shown in the diagram, right? If so, the screw was probably already adjusted to the lowest position. In this case, I'd recommend that you now troubleshoot the ECT sensor.

Have you checked whether the throttle cable is adjusted too tightly?

MHDesigns

Yes I have checked the throttle cable tension and there is as much play as you said there should be. I will probably check that ECT later today and see what the deal is. For now I have made a gasket that covers the IACV port from the tb and it runs nicely, no more haunting idle. I am just worried about doing damage to the motor like this. If anyone could confirm if this is horrifically wrong or not let me know. There is definitely coolant in the IACV and FITV. Coolant is bled every time I mess with one of them just to make sure all air is out. The motor runs with POWER again, just like its supposed to. It still has a cel(Dont have code reader on hand so I cant check till later) but runs great so I dont know what to do. I dont mind having a cel, but when emmissions comes I will be ****ed so I would like to do a proper fix on it. Thank you Ron and everyone else on HT who has helped so far. You have all been a great help.

Former User

You don't require a code reader to pull CEL codes, though the scan tool may retrieve codes with more detailed information. Click here.

You might achieve the same outcome by unplugging the IACV connector. Running with the IACV port blocked won't damage the engine, though the warm engine idle speed may be too low and will not ramp up under load such as when the A/C is turned on.

MHDesigns

I'm not running AC or PS or a stereo for that matter. The idle is actually low at startup and after warms up sits at around 1k rpm. It has a little trouble starting up but after it runs for 10 seconds its all good. I will be checking the ECT later. You rule ron. you have really really enlightened me on this whole situation.

Former User

This information suggests that the FITV is not working. Here's how to test:

HXor

Ron...I hope to holy h#$% you are a supreme master tech and get paid well for it. Your common sense approach and knowledge of where and what to do next are top notch - bar none. A true benefit to the Honda community .

1250b18c5

I think RonJ@HT is gotta be a Honda Dealer Tech, and a VERY good one at that! He seems to have some pretty neat access to OEM Honda Manual info.

I own a 1992 eh2 CX with a No-CEL/MIL 732 kilometer per tank D15Z1, and a 1992 eh2 B16 VX, and a third 2001 integra...I'm making RonJ@HT a contact! Your REALLY good Man.



COSIGN!

wshuculd

Its your ficv take the cover off and tighten it up