hillbillycivic

need help i think i got a vacume leak on my 98 civic.

the idle was at like 950-1000 at full running temp (florida temp outside) scan tool showed the temp sensor reading like 200*F at full temp

i pulled the codes and got
p0170 --- fuel trim problem
p0505 --- idle control problem

(pending code) p0171 --- to lean bank 1

i turned the idle screw a total of 1 full turn clockwise and it bottomed out and that brought me to an idle without the ac on to 850rpm.

alldata says it should be around 650 with ac off and 750 with ac on. so im way off.

o2 sensor voltage red 3.8 so ya im running lean.


soooo..... i think its a vacuum leak but i dont know how to find it i dont have a smoke machine and the only other way iv hear is spay carb cleaner on **** to see if the rpm spikes but thats never worked on any of the cars iv tryed it on.

Ryan Lwin

Fix the codes first.

dirty19

iTrader: (1)

Like ryan says fix the codes see how it runs then break out the carb cleaner

hillbillycivic

well the fuel trim code is to much air coming.

the 505... i dont know how to test an iac to see if its the problem and i dont have 187 dollars to get one from advance auto parts. so i gota test mine some how.


EDIT: i found this but its for a 2000 y8 with a manual mines is a y7 with a manual does it matter? cause mine has 3 wires going to it

unplug 2 pin iac conector if speed drops adjust base idle if no replace iac

plug lower port in throttle body if idle drops adjust idle if no find vacume leak

Ryan Lwin

Seems like your problem could be two things. IAC and O2 sensor. Check IAC for resistance and IAC plug for voltage. I don't remember the values on top of my head so Google that.

If IAC has 0 resistance, it's dead. Get one from junk yard. Make sure it's for Y7. Check the part #.

If IAC has resistance but plug has no voltage, then check the wires.

Take the intake out and close the throttle body. See if engine dies. If it doesn't, replace the TB gasket and check the hoses. Especially the PCV hose.

primerisfiner

try pulling off the iacv and cleaning it, see if it gets better.

hillbillycivic

i cleared the codes and pulled the ecu fuese for like 30 sec.

when i restarted the car with the iac unpluged it idles at like 1900 but when i was messing with the idle srew it dint nothing what what turnes the idle down clockwise or counterclockwise.

Ryan Lwin

hillbillycivic

okokokokok i took off the throttle body cleaned the entire thing and removed the iac cleaned that put it all back on with the idle screw in all the ay and im letting it idle hoping it relearns.

this idle screw cap? im a sapost to have one nothing was covering the screw and theres a little hole behind the screw but no cap or cover......


now its idling at like 2k but then it drops to like 700 almost dies then 2k then 700 almost dies back and forth back and forth ima see if any codes poped in a few min

DAMIT MAN I THINK I MADE IT WORSE BY CLEANING IT ALL OUT. WHAT THE HELL.

Ryan Lwin

I'm out of this thread. Sorry. Can't help someone who knows more than anyone else.

hillbillycivic

found the problem i think

i tryed pluging the throttle body with a book it killed the motor but it was still runing to high an idle when i started it back up.

i ended up pluging the hole above the throttle place to the iac (the long one not the circle one) and it fixed it.

so then i put a peice of duct tape over the hole adjusted the idle screw to 650-670 rpm like the books and websights say and bamm runs like a dream.


so i guess that means my iac valve was bad??????? it also got rid of all the other codes but poped a p10 something its says iac circute failed or something to that affect.

muddmonky

well if you pluged the hole that lets air bypass the throttle plate threw the iac and it made the idle go back to normal that means you iac was stuck open so ya i would asume it was bad.

i have no idea how to test the 3 wire ones so i would only be able to say replace it and hope for the best.