bleedblue94

well im at a loss on this one. car starts fine and idles pretty well at cold start...only a little putt putt can be heard in the exhaust. then once it warms the idle suddenly drops, then starts to climb slowly, goes to where it should be then drops again...each time it seems like its going to staul and eventually does. car seems to run fine the rest of the time. also once it stauls i hear a humming from the iacv, when i unplug it the hum stops, then when i plug it in again it clicks and humms again. once i turn the ignition off and turn it back in the on position again the humming is gone.

ive measuresd the voltage during idle and it holds steady at 14.5 volts and drops to 13 when the idle drops.

also measured the map sensor voltage and it reads 1.09 - 1.23 volts when warming up, then .90 - .93 volts then begins to fluctuate with the idle as expected between 1.50 - .90 volts

i also pulled the plugs that i recently put in and dont really see anything at all

cylinder 1
http://www.imagestation.com/pi...3.jpg

cylinder 2
http://www.imagestation.com/pi...0.jpg

cylinder 3
http://www.imagestation.com/pi...6.jpg

cylinder 4
http://www.imagestation.com/pi...c.jpg

this fluctuation is kind of drawn out in its cycle...not fast paced like a vacuum leak. also this is an obd2 b18b running off an obd1 p75.

ive tried new dizzy, map sensor, checked tps, clean iacv....just getting frustrated

kyorishin

same shiet is happening to me too bump for answers

bleedblue94

ttt

bleedblue94

forgot to mention i have a b16 tb on this motor so its not the fitv

bleedblue94

kgj;bso;uettutse

killerformula

Bump because mine does this too, only after warmed up. If you're sitting in traffic and can't have it stall on you, turn on the A/C. Turning on the air conditioning bumps the idle slightly because of the idle compensator.

I've done a bunch of research on this. Most people say its the idle air control valve, or the vacuum tube that leads up to it. Not a great part to just "try and replace" considering it costs close to 200 dollars.

K

killercannible

It dosn't really sound like an idle control problem. Its going through the warm up cycle and then returning to the stock honda idle which is like 600-800 rpms(for fuel saving). This sounds like your engine is struggling to run, Does it smoke? Compression? Thats my guesse.

killerformula

its not struggling to run, it runs smoothly, just the idle drops very low, past the low line on the tach. I would guess the RPM to be about 400 or so, its noticeably low, and has been tuned up within the last year.

If you search on this, you'll find that its a common problem.

bleedblue94

compression checks out all across the board....also the car runs vbery strong...its not compression

EGwhat!!!

have you checked your pcv valve

Out of every "game"

i think its your iacv honestly. if its idleing fine at cold and then all of a sudden it starts to jump idle at a warm it has to be. iacv controls the idle when the car is at normal temperature. happened to me. took it off and cleaned it out.

crisp afterwards

bleedblue94

i already cleaned the screen on it and have tried a different iacv....same exact thing

Out of every "game"

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bleedblue94 &raquo;</TD></TR><TR><TD CLASS="quote">i already cleaned the screen on it and have tried a different iacv....same exact thing</TD></TR></TABLE>

damn. then i would just check everything hoses, wires, ecu etc sorry i couldnt help

schardbody

play w/ the idle bleed screw on the TB, they are all calibrated differantly from the factory and lets say the target idle is 750, and the B16 TB is calibrated to idle at 700 or anything differant than 750 its going to make the IACV hunt for that particular rpm. might take a while to get it perfect, but i garuntee you thats the problem.

badcompany_2205

I know you have already herd this but it REALLY sounds like its a vaccum leak some where or maybe a hose that came off somewhere you cant see??? I had that happen to me one time, my buddy was messing around under the hood of my car and he accidently unpluged one of my vaccum hoses. Well i started it fine but after it warmed up it ran really crappy, also loss of power, and i could hear a humming coming out from the engine bay. Well we pulled over and figued out one of my hose was off, i put it back on and no more problem. Im not saying this is your specific problem but it might help you trouble shoot the real problem.

bleedblue94

the humming is def from the iacv, and you can only here it after the car dies.... for good measure i just tried a 3rd iacv and they all do the same thing.

its not a vacuum leak bc if i put my finger over the whole in the tb the car dies.

bleedblue94

today i did plugs, wires, replaced fpr, bled coolant, tried a 3rd iacv, did timing, replaced map sensor, tested tps

still same problem

mike1114

iTrader: (1)

ok I have an idle issue as well. It only surges when the car is warm. If I turn the lights on, the car idles perfect.

A few chimed in to my post (search my id for it to read up) and said it may be because of the cells on the fuel/timing map for the idle portion of the map. They even posted some example screen shots on whats wrong and how to fix it.

bleedblue94

well im running just a stock p75 ecu....nothing thats been programed

bleedblue94

ok here is the latest...i have gone over everything at this point, then today going on someones suggestion i unplugged the o2 sensor. the idle problems all seemed to go away. only problem i had was when i got off the gas all my lights would dim noticably and when i was driving and pushed the clutch in and stopped at a light the car let the idle drop to much and died. wondering if the problems could stem from someting not regulating the voltage of the electrical system? or from a faulty o2? do o2s go bad without throwing a code?

bleedblue94

also does anyone know why the secondary o2 sensors ground wire, signal wire, and heater wire all run into the car harness.....i was checking some things and found that on the 98 ex harness these wires go to the ecu, but also run to the green plug on the engine harness that plugs into the car harness.....wondering why???

ianae86

I'm just throwing this out, but try cleaning your throttle body out. Seems obviously stupid but who knows.

bleedblue94

did it

ianae86

You already cleaned it? Or you cleaned it and that did it?

bleedblue94

already did it about 3 times