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

sik96teg

isnt the voltage supposed to be under 13 on a good iacv not sure havent messed wit one in awhile. Is this a new build or is this a problem thats got worse over time

bleedblue94

i should clarify.....the voltage i meant was at the battery....as far as the voltage at the sensor, it all checks out

fysh

I was having similiar issues. Replaced the IACV and it didn't do a thing. My problem ended up being the FITV ( https://honda-tech.com/zerothread?id=1564019 ) try that and see if it fixes the problem. It takes about 15 minutes to do, and really doesnt cost you anything to try but a can of brake cleaner.

bleedblue94

unfortuanately thats not it bc i have a b16 throttle body on it which does not have a fast idle thermo valve

bleedblue94

ksgdbuibuis

sik96teg

dunno bro timming or valve adjustment maybe mine had a slow idle surge that u could tell wasnt a vacuum leak. so i did a valve adjustment and checked timing

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

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

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

YoungKadafi

same problem, you got an intake?

esohsee

i got the same problem... poorman's type r here though
i replaced my O2 sensor helped a bit and it kept it from dying.
i cleaned my iacv recently and when i tried to start the car it would just stall out... i adjusted the idle to make it driveable...
i was wondering if you guys are having problems setting your base idle... because i can't do it at all... i was thinking there is little air and the ecu is trying to compensate? but idk
tomorrow i'm gonna take my tb off and check around... maybe even mess with the throttle plate screw and different tps settings...

weird thing is... this all started to happen when i switched ecu's... i was running it on a jdm type r... ran great... then i had to return it and i started using a spoon p30, gsr, and usdm type r and they all idled funny... now i'm running hondata s100 with the same problem... and i'm tuned aswell

:::sorry if it seems like i'm threadjacking but this idle problem is killing me aswell goodluck on the ongoing battle:::

B18ceed

i have the same problem and i have just switched to a 3bar map sensor and it seems to die out when i play with the wiring leading from the stock map, ive replaced my iac also and nothing, so i hope its the map, im gonna rewire tomorrow i post what the outcome is.

hondarover_user

rough idle seems to be a permamnent feature of used honda efi engines. On my current f18a3 I've cleaned idle valves, throttle body, changed spark plugs, now idle is a bit more stable, but engines dies occasionally until it runs for about 10 minutes with load. After the engine bay is heated well problem of dying at idle disappears, while idle remains rough if to comapge with other engine 'brands'. Problem is annoying if not to say more, never had idle problems on 100k+ miles 4 bangers from volvo, bmw... Now i'm thinking to implant a selfmade idle speed controller, as honda ecu's logic of idle stabilisation seems to be very far from perfect, the delay while ecu is trying to recover from dropped below norm. idle rpm is too big and done only by adjusting the airflow through idle valve.