Ok, got a D16y7 in a 1996 civic hatch. When it warms up idle goes from 1k to 2k and back and forth. I've cleaned the IACV, nothing. I cover the tb with my palm, car shuts off, so no leaks. I unplug the plug for th IACV and idle bounces rapidly from 1.5k to 1.7k. However, I unplug the MAP sensor and idle becomes normal, but it stays at 1200rpm. What is the problem, I'm sick of figuring **** out. lol.

 

Any CEL codes?

Is a vacuum hose disconnected? Have you topped off the coolant in the radiator and bled the cooling system?

If you use your finger to cover the port inside the TB leading to the IACV, does the idle speed drop and steady?

 

No CEL's, no vacuum lines are disconnected and I haven't topped it off with coolant. But yes, if I partialy cover the port idle goes down and becomes normal, if I cover it all it stalls, of course.

 

Was it running like that when you bought it? or did it just recently start doing that?? and I ran into the same problem just last week and I was going crazy cuz I couldn't figure it out. I ended up buying a new ECU for it and it solved the problem. Try checking your ECU. GOOD LUCK!

 

Yeah, I bought it like this. Will a P06 ECU work? I have an extra one lying around.

EDIT: Nevermind, one is OBD1 and one is OBD2.

 

yea i had the same problem it ended up being my ecu or you could have a hacked up engine harness

 

Engine harness has neve been tampered with from what I can see. I'm going to try anothe ECU and see what happens.

 

1) Bleed the cooling system.

2) Test the TPS output voltages at closed and wide open throttle.

3) Measure the resistance across the two terminals of the ECT sensor when the engine is hot.

 

Have you found the problem yet? I've got the same problem with my B16A2, I recently rebuilt it and it never did it before. But when I finished it started surging. I changed the IACV already. I have not tried vacuum leaks, I just learned yesterday how to check for leaks. I tried what you did before, i unplugged the map sensor but it fluttered a little then started surging again. I am unaware of where the tb is (throttle body right?) to cover it up. I tried using my old LS vtec ECU (the ECU i was using before i rebuilt it) and it doesnt stay on with constant power. I have to hold the gas pedal for it to stay on. I have a new TPS but i dont have the tool to check voltage. But one thing that boggles me is when i drive. I cant stay at a constant speed. when i let go of the gas it jerks like im down shifting, and when i accelerate from that point, it jerks forward again like im accelerating really fast. I checked my CEL and I have code 14 - IACV but i already replaced it with a used working IACV. :X I'm so confused!

 

Ok, I bleed the cooling system and I went to the junkyard and got another TB with all the sensors and the IAC on it. Put it on and absaloutly no difference.

 

Don't thread jack. If you want your problem figured out, start your own thread. I will tell you this though. Your engine is OBD2, and hopefully you have an OBD2 diagnostic port. Your car is telling you more than the IACV. Get a diagnostic check and it'll be more specific than the CEL sticky is.

 

i had the same problem and believe it or not i changed my injectors with some known good one and that fixed the problem.

 

It was a faulty IACV. I tried another one and it fixed it.