B18C1 from a 98 GSR integra.
No FITV.
Cleaned IACV
I did "bleed" the cooling system.

Idle has a climbing problem. I figured I should be able to kill the car completly by placing my hand over the intake and completly sealing it off. However when this is done, the engine boggs down and a high pitch whine is heard. Engine never dies even when the intake is completly blocked off.

Video of current idle:

One thing I dont understand. I sprayed carb cleaner around the IM and got nothing. For a benchmark, i sprayed carb cleaner right into the intake and even then it didnt raise the idle. I didnt spray alot of it, but I would sure think it would at least raise the idle a little.
WTF? is carb cleaner not flamable anymore? Im so confused.

 

I know I have a vacuum leak and I was completely unable to find it with carb cleaner or propane. I'm taking it to a shop to get it smoke tested tomorrow. If you can seal the intake and the car still runs, 100% for sure you've got a vacuum leak. Even the IACV can't function with the intake blocked like that. I'll let you know how things go at the shop. If you want something else to try, use an unlit propane torch and spray it around the engine bay. Just be careful of things that could cause sparks!

Edit: Carb cleaner tends to cause bogging in my experience, not over-revving like you would think. And if you are in closed loop mode the ECU can compensate and you'll never notice a difference. I put mine in limp mode by bridging the service connector before looking for leaks.

 

Thanks for the advice, ill give the propane a try and see what comes up. Going to try and block off the intake again and test. Might get better results with the decreased air (choke the engine out).

Definatly let me know how it goes at the shop. I've been temped to go get a smoke bomb and light it up and see what happens haha.. just worried that it may get everywhere inside the bay.

*On second though, just had a look at some home made smoke machines and it looks faily simple. going to try that.

I'll make sure and bridge the connector also.

Thanks

 

Is this the same as jumping the blue 2-wire connector under the passenger side dash to pull ECU codes?

 

Yup that's what I meant.

 

Oh, ok - it's that I've never noticed that doing so will put the car in "limp mode" which forces a 3000 RPM rev limit on the ECU along with a solid CE light...

 

You're right about limp mode IDK what I was saying. But it does force open loop, correct?

 

Not sure about "open loop" but aside from allowing you to check codes, it does hold the timing stable so you can get your car to run at 16 degrees with a timing light

 

Open loop means it's not referencing the O2 sensors to correct fuel and ignition timing -- it's just looking up the map values.

 

I know very well what "open loop" is, just meant to say I'm not sure if jumping the CE connector actually forces open loop.

BTW, timing is not affected in open loop - only fuel...

 

Sorry -- I did not mean to offend you.

Keoman, I got back from the shop and... no vacuum leaks for me. Which I guess would explain why I couldn't find one with carb cleaner or propane. Hope you get things sorted out. A B18C powered Mini sounds like a lot of fun.

 

No leaks? Is that a good thing or a bad?
I have been working on things outside the engine for the time being. (Mostly what I can bring inside to get out of the cold!)
Next decent day we get I'm going to attack the leak and figure out what's the problem.

Thanks for the response and I agree, I am so anxious to get this thing on the road.

 

well, tried just about every type of technique to find a vacuum leak that i can find on the internet but cant seem to get anything. I completly disassembled the intake manifold and checked all the gaskets, hoses etc... and nothing. Tightened everything back up real good and was carful to ensure good seals on everything. Back to exactly where I was to begin with. Only thing I havnt tried yet is building a smoke machine. Going to hook the gauges up now and see what codes im getting. Im leaning more toward a sensor at this point but who knows.

 

Check for hairline crack in radiator (if plastic), loose radiator or heater hose etc. I just recently spent hours tracing a similar surge and it ended up being a hairline crack less than an inch long under the radiator cap. The crack only "fizzed teeny bubbles" of coolant after it reached operating temp.

 

Hey Rex,

sorry I'm relativly new to this. Could you explain how a coolant leak would cause the surging idle?

Oh, the Rad is all Aluminum also.

 

Is the correct gasket on the TB? Also the TB gasket not leaking?

 

Any possibility of air entering the coolant system will cause a surge.

 

TB gasket is in good shape. Replaced it about 2 months ago. I noticed that the GSR gasket did not fit the skunk2 copy manifold I purchased. I had to buy the type R gasket however it seemed to fit the TB just fine. The TB fits the bolt pattern on the IM so i assumed it would be fine... am I wrong?

 

Be careful some of the advice is pretty entertaining here. A cracked radiator will not create this problem. There is no fitv. Is it an oem throttle body? When you choke off the iac port the engine usually will die but sometimes they can pull air through the Pcv valve and barely keep going. Thats probably what the whining sound is. I would double check the throttle body gasket, stop screw on the butterfly and make sure the throttle cable has a touch of slack and isn't too tight.

 

Haha thanks guys.

TB is OEM from the 98 GSR as far as I know. I went out just now and dissasembled it all to snap a few pics.
Also tightened down the TPS a bit, seemed a little less snug than I would like.









The white circle there was what I thought the problem was. Turns out the hole is untapped and goes nowhere.



Went out and hooked up the gauges finally and pulled the ECU codes. Only flashed a 20 which is the ELD (i dont have it hooked up yet)

You say that it can pull air from the PCV, what would happen if I capped it off and plugged the IM nipple? Worth a shot?
I assume the Idle screw needs to be adjusted, just wasnt sure that I had changed it at all from the factory setting. Still has the yellow paint stripe down it marking the initial setting.

Other than that I think its time for a smoke tester for vacuum leaks.

 

The pics are small on my phone but it does look like an oem throttle body. In that case if the stop screw and idle screw are untouched you should be just fine to leave them where they are. If you want to plug off the PVC line go ahead. If the engine really idles low almost ready to shutoff I doubt you have a vacuum leak. There's really not much there to leak, and it sounds like you have covered everything pretty well. Double check the grommets at the injector base, they should have a slight compression in them to seal well. But really it sounds like the iac is just stuck in the full open position for whatever reason.

 

A crack in the radiator can cause an idle surge. Not necessarily this same exact surge lol. Why would I take time to post and lie about my problem/fix. In my particular case, the coolant level had decreased significantly while driving, steaming out coolant and allowing air in the system.

 

I'm not saying you were lying. But a cracked radiator will not cause this issue on his application. There is no Fitv to control the idle speed here. Air in the cooling system, will just create a cooling system problem.

 

Runner,
There are coolant hoses pipped to the IACV, what purpose do these serve? Could air in these lines cause any adverse effects on how the IACV works?

 

Completey stock 94' CX Civic. No Fitv here either. Air entered the coolant system and that resulted in a surging idle. However, after he explained the radiator was aluminum I basically ruled out my suggestion.

Keoman, I suggest fixing the ELD cel before moving on.