Ok so I just pulled out my old d15 and swapped in another d15 and now I have a bad idle surge.. All vacuum hoses are connected, iacv is good, no check engine light.. Anyone have any idea what it could be?

 

Have you cleaned and adjusted the FITV?

Any CEL codes?

 

No cel.bro.. And yes

 

Does the CEL work?

When the idle is surging, if you use your finger to cover the port inside the TB leading to the FITV or IACV, does the surging stop?

Have you tried bleeding the cooling system?

 

Could also be your PCV. You check your valve cover for leaks?

 

ended up being the fitv.. switched it out runs perfect now.. thanks honda-tech!!

 

RonJ, I have the same problem, what does it mean if I cover the hole to the IACV and the surging stops. Bad IACV?

Sorry for the threadjack...

 

1) Clean the IACV.

2) Bleed the cooling system.

3) Adjust the idle speed.

4) Test the ECT sensor and the TPS.

 

Cleaned the IACV (several times), swapped the radiator and bled the cooling system, can't seem to adjust the idle speed: the throttle cable is adjusted all the way out and has a little bit of slack, probably less than the recommended .5 inch, but it's all I can get; and the idle screw on the tb is all the way in, messing with it doesn't steady anything (even with the jumper in), aaaaaand I haven't tested the ect or tps yet, those are new.

Here's everything I've done so far:
https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/95-civic-dx-coupe-mini-me-engine-%2Aanother-bouncy-idle-thread%2A-2958801/

 

Any CEL codes? 95 Civic? What happens to the idle speed if you unplug the IACV?

Did you calibrate the TPS?

Did you do this:

Bleeding the cooling system may take 20-30 minutes.

1) Park the car on an inclined driveway with the front end higher than the rear.

2) Push the dash heater lever/**** to MAX heat.

3) Follow the directions in the diagram below (hint: the bleed bolt is located where the upper radiator hose connects to the engine):

 

I did the cooling system bleed like that- and my driveway is even on an incline.
When I unplug the IACV with the car running it calms down quite a bit, not down to where a normal idle *should* be (450 warm, 720 cold, right?), but right around 1300. I almost want to say that it's stuck open? I did the battery test on it, and I saw it click a little each way, but with the screen there, I can't really tell for sure if it's seating all the way or not.

 

With the IACV unplugged, are you able to reduce the idle speed by turning the idle adjust screw?

How much slack does the throttle cable have? Why can't you adjust it? Have you tried cleaning the throttle body to ensure that the throttle plate is not stuck open?

 

With the IACV unplugged, I can back the adjust screw out and it increases the idle a little. I would say that it has about 1/4 inch slack- I can't adjust it any more for slack, it's 'bottomed out' so to speak, all the threading is to the left of the adjustment bracket. I sprayed out the TB and the throttle plate, but I didn't want to get too aggressive with any brushing and ruin anything without making sure if it's ok..... so, is it ok? Plastic, steel, or brass brush?

 

I'm really finding out more and more that the guys that did the work on the swap for me are really just lazy jerks that did a half assed job, it really wasn't that good of a 'deal' to pay $600 for an engine and work if I'm going to have to keep making fixes like this.

 

For future references, I had the same problem and replaced everything on the throttle body and nothing worked. It ended up being a vacuum hose on the charcoal canister on the back of the block came unplugged!!!