Bond

Just as of a few days ago this started happening. When My car is either warmed up or not, when I step on the brake my idle drops to like 300/400rpm. If I hold it there I can almost get it to drop around 200rpm. Also when I have the car running hot or cold and I pump the brake pedal quickly it makes my idle go up. When warm I can get it to go just above 1000rpm just pumping the brake. What's wrong with my car? Sometime when I start the car up in the morning the idle surges but then goes away. I really don't know why this is happening with the brake and idle. I figure alt. Can you guy's help me out?

hatchling37

It's a hydraulic braking system, so when you are demanding extra gripping power from your brakes (when you are pumping the brakes), the ECU is alotting more power from the motor to assist in the clamping force the calipers put on the rotors. That's why your car is dipping in RPM, but your low idle is something else. You should check out your timing, and check plugs and other parts related to timing. If that all checks out, fuel filter might be another factor relating to your problem.
Just my $.02

Bond

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hatchling37 &raquo;</TD></TR><TR><TD CLASS="quote">It's a hydraulic braking system, so when you are demanding extra gripping power from your brakes (when you are pumping the brakes), the ECU is alotting more power from the motor to assist in the clamping force the calipers put on the rotors. That's why your car is dipping in RPM, but your low idle is something else. You should check out your timing, and check plugs and other parts related to timing. If that all checks out, fuel filter might be another factor relating to your problem.
Just my $.02</TD></TR></TABLE>

But when I pump the brakes the rpm goes above 1000 at a complete stand still and just idling. When I hold the brake down I can see why the rpm drops. Anybody else have an idea or any help?

Bond

Bump

clutcher

When you press the brakes, the air that goes through the throttle body and intake manifold is directed to the brake booster which needs air to operate so the rpms lowers since the air is not being used for engine power but for brake power instead.

As far as your surging on cold, check your FITV (it's a bulky part under your throttle body--92-95 civics for sure). Remove it, open it up, and screw the "plunger" as much as you can. Put it back together, and that should fix that.

Post updates.

Bond

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by clutcher &raquo;</TD></TR><TR><TD CLASS="quote">When you press the brakes, the air that goes through the throttle body and intake manifold is directed to the brake booster which needs air to operate so the rpms lowers since the air is not being used for engine power but for brake power instead.

As far as your surging on cold, check your FITV (it's a bulky part under your throttle body--92-95 civics for sure). Remove it, open it up, and screw the "plunger" as much as you can. Put it back together, and that should fix that.

Post updates.</TD></TR></TABLE>

Thanks for the help. I will do that tomorrow and see if it helps as it is getting a little late here on the westcoast. Just another question though. Do you know why my idle raises to over 1000rpm when i pump my brake pedal at idle? I will post updates tomorrow when I give the FITV a looking over.

94 Civic Si

Sounds like you have a vacuum leak with the brake booster...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Bond &raquo;</TD></TR><TR><TD CLASS="quote">

Thanks for the help. I will do that tomorrow and see if it helps as it is getting a little late here on the westcoast. Just another question though. Do you know why my idle raises to over 1000rpm when i pump my brake pedal at idle? I will post updates tomorrow when I give the FITV a looking over.</TD></TR></TABLE>