Hello every honda lover, my civic ek3 (1997) got some problems and want to seek advice.

Once the brake is applied when i was waiting for the traffic light, the Revolution(RPM) rose up to 1500 and drop (keep Looping). Is there any idea for fixing this problem?

P.S
I have cleaned the IACV and Throttle Body.. problem still exist

Thanks all.

 

By "resolution" I'm assuming you mean the engine rpms? If so, pull the air intake tube off the throttle body and look in there. If it's all black and nasty try cleaning it out with some throttle body cleaner from your local parts store. If that doesn't work, you'll need to pull the IACV and clean it out too.

 

Yes, it is RPM. I have cleaned the IACV.. problem still exist

 

What about the Throttle Body? If neither of those are it the next most likely culprit is a vacuum leak. I know some of the hoses on the back of the intake manifold like to develop small leaks that can wreak havoc on idle quality.

 

Throttle Body has been cleaned as well.

 

1. Remove the air cleaner assembly and find the bypass port that feeds air to the Idle Air Control (IAC) valve. Block it with a finger when the engine is running. The idle should slow down and stop surging.

2. Cover the throttle body and verify that the engine stalls. If the engine stalls, there are no vacuum leaks.

3. Locate the IAC valve 3-wire connector. With the vehicle running, back probe and ground the Orange (ORN) wire and the idle should decrease. If the idle does not decrease or slow way down, remove the IAC valve and see if it is sticking.

 

Manual or automatic? If it is a manual EX you have a two-wire IACV, the automatic EX and all DX or LX are three wire.

Put the parking brake on and release the brake pedal. Does it idle normally? The rpm may increase slightly when the brake pedal is first pressed or released. It should return to normal while the pedal is held down. If pressing the brake makes the idle go up and stay up, the brake booster is faulty. That should be replaced because it is likely to get worse and make it hard to stop the car.

 

It is a manual (vtec). After released the brake, (idle) the rpm goes up and down

 

Replace the rubber seal between the master cylinder and the brake booster (#3 in image below). It's a vacuum seal. You may even hear a hiss at this location when the brake is applied. Be sure to clean & grease the master cylinder push-rod AND grease the new seal with silicone grease before you install it. This you just un-bolt the master from the booster and slide it forward. There should be enough room to replace the seal without un-bolting any fluid lines.

If this "cheap-fix" part doesn't solve your problem, you may have a leaking brake booster (expensive fix).

 

Before doing what 94eg said, remove the large vacuum hose that goes to the brake booster and block it off. Start the vehicle and try to reproduce the idle problem. BEAR IN MIND YOU WILL NOT HAVE POWER BRAKES!!! If the problem still exists, it's not a brake booster related issue. If it goes away, carry on with what 94eg said.