Tippyman

I just finished helping a buddy swap in a 1994 B18 from HMO. After we got it in, it wouldn't start, but I changed the ignition coil and it finally started.

There's a couple problems however:

1) The idle is really low. Like less than 500 rpm. It started cold at like 1500 like it should but after it warmed up it was waaaay too low, it felt like it was about to die. I turned the idle screw up, and the idle raised when I turned it, but after I was done turning it up, it would go back down after a few seconds. The idle is not surging or anything, just really low.

2) There is a really loud "sucking" noise coming from the throttle body area. I know Honda's with CAI's usually do this, but this was LOUD. When I took off the intake, it was definitely coming from the TB area. It got alot louder the more the idle went up. It sounds like Darth Vader on a constant inhale.

Any suggestions?

B serious

iTrader: (1)

it's more than likely your IAC. Either it's not plugged in, or you got the plugs mixed up.

It is located on the back of the intake manifold right by the firewall/fuel filter.

It lets air in while the throttle is closed so that your car can idle. If it cant regulate the it's piston postion to let air in or keep air out, it will go into that 500rpm idle mode and make a loud *** sucking noise.

You should never turn the idle screw (future reference). Seeing as how the idle corrected itself, im guessing that the IAC is active, but not operating properly. Check all wiring connections...make sure you dont have another plug plugged into there.


What kind of car did this go into?

Make sure your injectors are wired correctly.

Tippyman

BUMP

yoffer

^^ what he said, Its def your iacv. The "sucking" noise that you are hearing is the tb sucking in lots of air to raise the idle up, but the iacv is what smoothes everything out. It you notice, when you turn down the idle screw the sucking noise will slowly decrease. Are you throwing any CEL's? To correctly set the idle, i believe the idle should be around 500rpm to 800rpm, or around that. Your suppose to have the engine completely warmed up, turn the motor off after it is warmed up and disconnect the iacv, turn the engine back on and your idle will be thrown off by the iacv not being plugged in. If your car doesnt even come on, then go to the idle screw and screw it OUTWARDS, as if your were looseing the screw, now only screw it out about 1/4 a turn. Go back and start the car, if it doesnt start repeat the steps with the idle screw until it does start. Now with the iacv unplugged, set the idle at about 700rpm with the idle screw. Now turn your car off after you have done this, plug your iacv back in. If your car starts fine and idles good, your set. All that is left is to go to your relay box in the engine bay and unplug the HAZARD fuse and the BACKUP fuse for TEN SECONDS!! This is because you will throw a code for your iacv not being plugged in. This will erase the code from your ecu memory and reset the ecu. Turn your car back on and your good to go.

Tippyman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">^^ what he said, Its def your iacv. The "sucking" noise that you are hearing is the tb sucking in lots of air to raise the idle up, but the iacv is what smoothes everything out.</TD></TR></TABLE>

This sucking noise is LOUD. It's not like a normal honda, it's freaking loud. Is that what happens when the IACV is messed up?

yoffer

If the iacv is messed up or not even connected your idle will be very low and not very stable. Is there even a iacv hooked up to the intake manifold at all? If not that sucking noise might be coming from the holes where the iacv is suppose to be.

yoffer

here is what a iacv looks like. It connects to the back of the intake manifold.

Tippyman

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by yoffer &raquo;</TD></TR><TR><TD CLASS="quote">If the iacv is messed up or not even connected your idle will be very low and not very stable. Is there even a iacv hooked up to the intake manifold at all? If not that sucking noise might be coming from the holes where the iacv is suppose to be.</TD></TR></TABLE>

No, it's def there.

CivicSiRX

if not the iacv, check the fitv, which is located under the throttle body. it might need to be cleaned out and have the piston on the inside turn back down. do a search on here for it.

preludedriva

my swap had same prob but after it hit operating temp it would die it was the IACV for me hopefully same for you

calorgan

look inside the throttle body there should be two holes the upper goes to the IAC, the lower goes to the FITV put your finger over one at at a time if your idle is corrected while your finger is blocking one then you can narrow it down to the one that made a change