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 in a 98 hatch.

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

bleedblue94

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

bleedblue94

gjdnioht'pt

bleedblue94

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

still same problem

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???

bleedblue94

so i was watching the fuel pressure today when the motor stalls..and i noticed that just as it dies the pressure shoots up to that of wot....so i then removed the hose from the fpr to the im and i plugged the im hole and left the fpr one open, so the car was getting more pressure at idle.....and it seems to stop the problem.......

i have tried 2 other fpr and i have the same problems when everything is hooked up so im wondering if this could be a sign of a fuel pump dieing or what.....pressure is coming up just how it should according to a helms at idle ut likei said when i trickthe fpr to think it runig wo he ca ems to dle fine.....any advice??? btw there is a enom fuel pump on this car

who-got-rice

you might laugh at this but have you checked your coolant lately, considering that that is what controlls your idle air control valve (iacv), if you have any air in the lines or if the level is a tad too low it will do what you are discribing, just a thought for you.

bleedblue94

im wondering if its the alt bc last year my old one died and i needed the car the same day....no parts stores had any and then i got one, but it wasnt for my car...they gave me the wrong one, but i had no choice so i grinded out the mount holes and got it to fit and such and ran it like that....but im wondering if even since the alt was for another honda motor if the voltage regulator is different....i have a feeling the guy at the shop gave me a d series alt, but im not sure....in any event the plug fits perfect, but im still having the idle problems and im trying to figure this all out....so far this is the only thing i can think of that i have transfered from the old motor to the new motor that could be causing this.;....and i honestly cant remember if this started at the same time as i changed the alt last year