dymond792

i have a 2000 civic si that had been sittin since 07. just swap out the engine with a 99 si engine a couple wks ago now CEL is on checked code possible vac leak. how do you find where it is? the honda place is gonna charge me $90 diagnostic fee and what ever else. i already know the diagnosis i just want to fix the problem. i dont have that kinda money right now since ive been laid off for 4mos please help.

sirt_eg

check your cel. what code is it giving you? check around your pcv. see if all the hose are connected and in the proper place.

suthernbred904

x2, and buy a can of carb cleaner and spray around the manifold. usually you can find it. thats usually if your idle is off and not balancing out...

Former User

Yeah, what CEL code? Below are the vacuum connections and hoses to check. Also consider leaks from the intake manifold and throttle body gaskets.

95jeremie

kick *** Ron
good advice

dymond792

my bro took it to a friend of his who has diagnostic device. he didnt tell me what code no# it was jus that there was a vacuum leak. thanks for all the replies

Former User

I don't know of a CEL code that specifically indicates a vacuum leak. Usually such a CEL code will include a vacuum leak as one of the possibilities. I mention this to you just in case you don't find the expected vacuum leak and have to look elsewhere.

JohnnyWash1

I had a vacuum leak with the exact same engine. Turned out to be the cruise control on the back of the manifold.

95jeremie

did he erase the code?
if not take it to autozone
they will scan it and give you a print out of the possibilities of the cause
for free...
i have heard of people spraying carb cleaner to help find vacuum leaks
i just look... it's not that hard if you have a diagram
GL

heritage36

There is no code from honda that is actually for a vacuum leak at the code name

dymond792

Thanks 95Jeremie i didnt know autozone did that for free. i checked for the leaks i couldnt find any so ill run out and check out auto zone 2day.

dymond792

Thanks for the diagram

joelmatt89

yeah i don't really like the carb cleaner trick i mean it works great if your leak is on the top side, but if the leak is somewhere on the bottom it doesn't really work. What works for me is just running my fingers along every possible spot that could leak. You can usually feel it. Have you tried covering your throttle body with the car idling to see if it dies.

MonkeyMagic

i wanna know when the last time i saw a fluxuating idle that was actually caused by a vacuum hose/nipple

except for the cruise control one earlier, that would've got me too lol

OP pull the code, so we can give you answers. ill almost guarantee its IACV code.

HaNgTiZZy

thanks for the info i needed it as well

dymond792

i'll try that too thanks

honda.lioness

Get that code. Then if the causes are a possible vacuum leak, and assuming you have checked all hose connections, the two best tools I have found are:
1. an ordinary length of tygon tubing, around 3/8" diameter, holding one end to your ear and the other to suspected leaking locations. Like a buck at Home Depot for a few feet. Very effective at amplifying leaking air. You can buy an automotive stethoscope pretty cheaply, too, for this. I found leaks around my throttle body gasket using this.
2. for hose checks, a hand held Mityvac (or other maker) vacuum pump. Indispensable. I think Autozone and Harbor Freight now sell these for around $15.

I do not like spraying carb cleaner around. It leaves a residue that is annoying to clean up.

quickster

What is the process for the carb cleaner trick?

What do you look for when you spray it?

are the throttle body hoses supposed to have pressure? mine dont seem to have any.