Honda people!

[ziich]

Anyone wanna figure out what's wrong with my car? I've got a fluctuating idle problem and the car is jerky when letting off the gas (as if the motor is still revs all the time, not just at idle). Bounces around from 1k-2k.

IACV swapped with an older known working one (JDM B16 OBD1) lowered idle a little bit.
Brand new TPS on a new edelbrock throttle body
MAP sensor swapped, no difference.
Searched for vaccuum leaks, to no avail.
Bled coolant several times.

It's kind of steady when cold, until you blip the throttle a couple times, then it starts to fluctuate again.

my distributer timing is off too, don't know how to use the gun to adjust it.

fix my car, i'll buy you a case.

[.RJ]

Is the new TPS a new honda TPS?

Check the grounds on the engine bay wiring harness as well, if the MAP/IACV/etc isnt feeding a good signal to the ecu, it can cause this.

[ziich]

not sure about the TPS. looks the same as OEM. Edelbrock ships their TB's with new TPSs installed. I'll check the grounds.

[.RJ]

I have a known good honda TPS if you need an extra to try out

[Evan]

first fix timing.

but it sounds like a vacuum leak to me

[ziich]

found 2 vaccuum leaks and fixed them.
had one bad ground on the thermometer housing, fixed that.
cleaned out iacv again.
reset ecu
The thing still doesn't idle! I don't have an FITV, so that's not the problem. When I block the air passage to the IACV, the car dies, so I guess that means there are no more vaccuum leaks.

how many grounds should i have?

set it on fire?

[Andy]

If the idle is steady when cold then starts to fluctuate when warm, it could mean two things.

FITV is good.

IACV is not able to operate properly due to bubbles in the coolant or you have more vacuum leaks.

I was chasing down this idle problem for six months on the prelude. Did you get a Skunk2 Intake manifold? Have you checked the manifold gasket? If you used a thermoplastic one then it's even more likely that it's not sealing properly.

[ziich]

Manifold is stock and hasn't been removed. No reason for the stock gasket to be bad, I don't think.

I've tried bleeding the air out of the coolant a few times. (leave radiator cap off, run car with the heat on full?). Though while checking for vacuum leaks, I often remove and reinstall coolant hoses which might introduce air back into the system. I'll try doing a flush and then bleed it again.

On another note, I hate how my clutch pedal feels. The engagement point is too low and unpredictable at times... or maybe i suck at driving.
but anyhow, anyone wanna help me redo my clutch pressure and do a valve adjustment? (or I might wait till I get my new crank and do all that with the installation).

[.RJ]

You can adjust the clutch pedal so that it engages further off the floor... i think its a pair of 17mm nuts. Once you get under the dash its pretty obvious how it works

[Andy]

How did you test for vacuum leaks?

[ziich]

I was told to just spray carb cleaner around while the motor was running, but I didn't find any that way. I actually just pulled all the hoses, stretched them out and looked for cracks/tears. I found one, with a small tear and then I realized that I didn't block off the vacuum lines from when i removed the cruise control. :hammer:

[ziich]

Back from the dead!

So after having the crappy idle for around 8 months, I had an epiphany and fixed it this morning.

I have a 65mm JG edelbrock throttle body. There's an adjustment screw that can control the position of the throttle plate at 0 throttle. It was set so that the plate was slightly open at 0. Visually I couldn't tell that the plate was open, which is why I didn't figure it out sooner.

So it was still taking in a good amount of air at idle causing the idle control valve to go crazy. I just made sure the plate was closing all the way and voila.

steady 800rpm idle.

I was elated.

[ScottyB]

wow....i wish most car problems were that easy

[NTIman]

wow....i wish most car problems were that easy

Most problems are that easy. none of us are lucky enough to have most problems though