Idle hunt and emissions question.

[jackmode9316]

I have a blasted idle hunt(idle bounces) on my 88REXsi(d15b,p08 swap)
Will they test my car even though the idle is surging/hunting? I know its a fairly easy fix but...Hopefully someone knows.
Thanks In Advance.

[HONDA GHANDI]

depends on how bad it is. The testers at those places are about 3 brain cells shy of a rotten tomato so I don't think it matters. It is merely a cash factory for the state.

[jackmode9316]

It bounces between 1k and 1.5k and is pretty noticable. I just figured they might need to read emissions at idle or whatever. Also if I plug the top vent hole in my Throttle Body(the one that is for IACV) and the idle drops to low, or normal, does that mean that my IACV needs cleaned replaced? I know my FITV need tightned but when I plug that, it does not fix the idle.

[HONDA GHANDI]

it usually means you have a vacuum leak downstream of the IACV.

[jackmode9316]

Would blowing smoke in that area work to check for vaccum leaks also?(as opposed to spraying with carb cleaner)

Edit: I did also notice that when I had the front of the car jacked up, and the intake tube off, the car seemed to idle just fine. I couldn't actually get it to bounce at that point(but it did after i put everything back together and drove down the block.). any ideas? Coolant bubbles?
Also The car only has the bouncing idle issue when it is at operating temperature. if that helps.

[jackmode9316]

Anybody got any nifty secrets to checking for Vacume leaks? Besides the carb cleaner method? Any help as I have to do massive work on the Ol Girl tonight? I would like to cover all bases.

[Blownbimer]

Why dont you want to use carb cleaner? The reason behind that it to listen for the idle to change to get a better pinpoint. If its a small leak, I think it would be very hard to just watch to see where smoke would be sucking in unless it was a huge leak.That CRX should have very few vac lines, so It probably wouldnt be that hard/ expensive to just replace them. You have to figure most of them are probably 19 years old.

Have you been driving the car? did you have the cooling system open? make sure you have burped the cooling system. maybe you have an air bubble hiding out by the temp sensor?

OH! I saw your exhast thread and if your ever in the broomfield area and want to hear a thermal cat back, I have one of those on my 88 Rex SI. I'd be more then happy to take you for a ride.

[jackmode9316]

Why dont you want to use carb cleaner? The reason behind that it to listen for the idle to change to get a better pinpoint. If its a small leak, I think it would be very hard to just watch to see where smoke would be sucking in unless it was a huge leak.That CRX should have very few vac lines, so It probably wouldnt be that hard/ expensive to just replace them. You have to figure most of them are probably 19 years old.

Have you been driving the car? did you have the cooling system open? make sure you have burped the cooling system. maybe you have an air bubble hiding out by the temp sensor?

OH! I saw your exhast thread and if your ever in the broomfield area and want to hear a thermal cat back, I have one of those on my 88 Rex SI. I'd be more then happy to take you for a ride.

Well I did spray Chemtool around and it appears that the it had little to no effect when I would spray it around different spots. Tonight I am going to Replace the Manifold gasket because it is a thick piece of white plastic that I re-used when I did the headgasket.I also noticed that it looks like there is some oil underneath where the manifold meets the head near cylinder 4. It doesn't seem that my idle is high enough on a cold start either, so Ill also crank down the FITV plunger. I will also replace the PCV valve for piece of mind. Only other thing that I can think it could be is fuel Pressure. Or that my IACV is just plain shot. But it did click when I attached power and ground to the plug.
Too much fuel pressur could cause idle surge right?
Is there any way to check the IACV without it being on the car? It did make a click sound when I attached power and ground to the plug.

[hrcDSM719]

It is possible to be a faulty IACV, but more common is low coolant level. Also, intake cleaner is the easiest way to find vacuum leaks. Hope that helps

[jackmode9316]

I got my heart set on a bad IACV because a vacume leak would cause issues even when cold right? Where as in this case the idle ONLY bounces when the engine is fully warmed up. Am I correct in this assumption, or is it possible for a vacume leak to not screw with idle at all until warm?
ALSO radiator is full, and so is the Overflow.

[jackmode9316]

Well I passed emissions yesterday. Just used the ol "aluminum can" IACV block off plate...idle was fine. Also passed just over half of the maximum.

[hrcDSM719]

A vacuum leak will have an effect wheather cold or hot. The thing is though:
when a vehicle(i.e. your car)is cold, or warming up, it will idle higher, therefore hiding the effects of a vacuum leak. If you said you sprayed it down (I assume all over the intake manifold side of the engine;t-body, injectors, head to mani flange) with no results, then I would think a vacuum leak would not be the cause.

Now, when you said that your car seemed to idle just fine with the front end raised up a bit, it made me think that you may have some bubbles in your cooling system. With the front of the vehicle in the air, it will make any air in the system go to the higest point(most likely the radiator cap) and allow your iacv to recieve the propper amount of coolant, therefore rectifying the idle issue.

Furthermore, it has happened to me before. My car looked like the coolant level was normal, until I raised the front, removed the cap, turned the heater selection to hot(blower off) and proceeded to fill the coolant slowly(car running @ idle). It worked for me!

Im not saying that your iacv couldnt be bad, or that you dont have a vacuum leak, im jus trying to help by adding my own .02 based off prior experiences. Hope that helps!

[jackmode9316]

WOrd! Its stuff like that that I like to hear. I will probably do a coolant bleed this weekend when I change the oil and whatnot. Thanks for your input!

[hrcDSM719]

Not a problem, keep me posted!

[jackmode9316]

I plan to swap with new IACV, maybe a FITV if the bleed doesn't solve it. Although The IACV block off seems to fix all idle issues(except when cold)