I have one problem with my car and it's gettin on my nerves,
Car don't won't to idle nice we just can't set the TB position so
The car would idle like it should, right from the start it was jumping from
1000rpm to 1700rpm I thought it was the sensor that is behind the IM
(the idle regulator I think ) but I changed that one and the only thing that
happend was the car was now jumping from 1000rpm to 1400rpm still
anoying as hell, I hope you can imagine that I'm standing at the red light and
everyone thinks that I wan't to race them … not good feeling :0(
But now when it's the end of summer and the temp are starting to get lower,
Car was acting funny in the morning when I start it it's going to 1500rpm and
Then when I drive for about 10-20miles engine not warmed yet rpms fall and
When I stop it jumps from 1000-1500rpm and then after 3s or less fall on 500rpm
And engine stops, so yestrady I tried to fix that with the gas cable I position that
One onto 1500rpm on idle position and it worked fine it (rpm pointer)
didn't jump anymore but when the engine got warm rpm meter go crazy engine
is now rewing from 1500 to 2700rpm or more and when I stop it's still on 2700rpm
and than after 3-5s falls on 1500rpm…
I really don't know what to do we tried everything…what would cause that !?
Which sensor is gone bad or something like that…
Anyone else had that kinf of problem
Help needed, every advice is apriciated

THNX for help

CYA

Car:
4th gen civic with B16A2 with some ITR parts !

 

The ECU relies on the fact that the ONLY additional source of air (besides what the IACV contributes) getting into the manifold is coming from the idle air bypass screw.

The other screw, throttle plate stop screw, moves the throttle butterfly which also affects TPS output. The ECU also relies on the fact that the throttle butterfly is set to NOT allow additional air around itself (but is set so that it does not fully seat in the bore - this would round out the bore causing a constant vaccum leak) which also happens to produce a TPS voltage in the area of .45v.

Adjusting the throttle cable to do anything concerning the idle is a no-no as is touching the throttle plate stop screw.

The idle oscillates because of the fuel cut strategy that the Honda ECU uses to save fuel. Basically, if the ECU sees the TPS is <.45v and engine rpm is above 1100rpm, the fuel injectors are cut off to save gas. As an example, coasting down a hill will produce the fuel cut, assuming you let off the gas pedal.

With Speed-Density metered fuel injection systems, ANY additional air getting into the manifold only serves to raise the engine speed - just like stepping on the throttle. Now, if a hose was loose - this is a source of unmetered air. Torn gaskets - another source. Misadjusted throttle butterfly - yet another.

So in a nut shell, it seems you have a vaccum leak.

I would also make sure that you have bled the coolant system properly. The engine needs a higher idle speed when its cold - it knows this by looking at the ECT sensor. However, if not bled properly, the ECT will send a messed up signal to the ECU indicating thats its at operating temp but then all-of-a-sudden its cold and as described, a cold engine wants a higher idle and so you'll get some oscillation from that.

 

yup he's right. ive had the same problem on my integra ls for half a year now. I adjusted the idle on the TB, changed fuel filter, and oil as well. now its runnin smooth like it was before.