Car info:95 Civic CDM CX Hatch,
4-2-1 2.25"-2.5" exhaust, Header to Tailpipe with High flow Catalytic converter and Fart Can muffler,
AEM short Ram with AEM Dryflow Velocity Stack Filter,
D16Z6 swap with Stock P28 Manual ECU and 95 Si (B000) transmission.
Intake Manifold appears to be the JDM D16A IM.

Okay all, got a question now that I actually sat down and attempted doing the FSM idle adjustment.

My laser tachometer records up to 96 seconds and displays high, low and the Last Actual I believe it said.

Now with the IACV unplugged, the idle fluctuates a bit. My low would be 380-400 and then the high would be 520 or so.

My question is, do you base your idle on the low or do you do an average of the high and low? FSM doesn't really give any details in that department just spec of 420 +/- 50 etc.

 

So 420rpm's, with a range of +/- 50rpm. I'm assuming that means between 420 - 470rpm's. I assuming its by range.

 

Stock engine and ECU?

Are the IACV, FITV, and PCV valve clean, and is the ignition system tuned up? If so, start by adjusting the idle speed above specification (>470 rpm). Is the idle now more stable at this higher speed? If so, slowly turn the screw back to reduce the idle to see if you can achieve a steady lower idle speed within the specified range.

 

Stock ECU (not chipped) P28. Engine isn't completely stock D16Z6, the IM is from a JDM D16A (P32 IM) which as far as I can tell has the same specifications as the D16Z6 IM but has one less coolant nipple. I honestly don't know if the camshaft is stock or if a stage 2 or better cam was thrown into the motor before I got it. The idle is lopey which does bring me to another one of my questions.

Do you still use the stock idle specifications if you use a bigger cam shaft on a stock ECU? Previous owner had the idle set high (600 range without IACV) and had ultra grayed the idle adjustment screw.

I'll be honest, I have not removed the IACV or the FITV as I just put the motor in. Allegedly the motor was just recently rebuilt and the compression test I did before buying the parts car (with half the exhaust missing) did have perfectly even compression of 185 on all four WOT. Everything on the motor looks really clean so I figured it all was. It runs really well but does seem to have the lopey idle.

It's actually idling a bit better now that I lowered the idle, I just wasn't sure if I have lowered it enough as only the low idle speed is withing spec. And the engine struggles more the lower the idle goes without the IACV plugged in.

From what you are saying I am getting not an average, not just the low and not just the high, it's supposed to be pretty steady if all is well.

What's interesting, I wouldn't even be able to notice the rpm was variable but the tach would tell me it had a low and a high.
Actually wouldn't it be a range of 370-470? And if I can't see the rpm fluctuate when doing the reading but the tach shows the variance, should I get the average in that range, the low in that range, the high in that range or should all 3 be in that range?

 

Researching this a bit, I see if bigger cams are used, there is likely to be changes to the base idle specifications.

Reading this article:
http://www.masterenginetuner.com/ls-big-cam-idle.html

And a quick glance through this article:
Idle Tuning How-To & Guide (w/pictures))

Tells me if they did use a bigger cam in the motor I bought, they should have chipped and tuned the ECU which they did not. And would explain the increased base idle. The silicone over the idle adjustment screw could be as a tamper deterrent or maybe the screw backs out otherwise.

I guess I won't know until I rip into the head, which.... I don't want to do, it runs decently, just idles a little off. But with the increased base idle, the rpm doesn't seek on decal like it is doing now that I've reduced the idle....

When I get adventurous, I'll chip and tune the car and I'm sure I'll learn a thing or two without having to tear the motor apart.

This part tells me there is something different with the motor I bought:
If you performed steps 1-3 properly and your engine is able to idle smoothly, goose the throttle while at idle and note what your engine does. Generally one of four things will happen:
1. The engine revs up and then decelerates toward idle smoothly and steadily and returns to the target idle without overshooting or undershooting the target idle speed.


2. The engine revs up and then the engine speed hangs for a moment and then slowly returns to idle, undershooting the target idle speed and taking too long to return to the target idle speed.


3. The engine revs up and then decelerates rather quickly and overshoots the target idle speed and stalls.


4. The engine revs up and then decelerates rather quickly and overshoots the target idle speed but doesn't stall, and instead recovers and then momentarily hunts for idle, criss-crossing the target idle speed several times before finally settling in at the target idle speed.

This is where I am at now that I reduced idle closer to factory spec. Accept it's not criss-crossing several time, just overshooting then returning to idle speed. I believe option #1 is the goal.

In scenarios 3 and 4, you may need to add more Base Running Airflow at the critical engine speeds you're experiencing issues with and use the Throttle Follower tables to trim for the desired result. Note that with a long duration / high-lift cam, you may have so much air flow in the Airflow Final Minimum table that you may find that you may need to reduce all of the Throttle Follower values to prevent hunting. If this seems to be the case, you have another step you can take to sort out the last bit of your idle woes and that is to go on to Step 5.

And the way they increased base running airflow was to adjust the idle screw to a higher base idle... Their work around without actually tuning the car with a stock ECU.

Interesting puzzle buying a used motor from someone else.

 

I just discovered that Factory would put a rubber coating over the idle adjustment screw while reading up on team-integra's forums.

So, my assumption previous owner used ultra gray seems less likely and it's more likely it's a stock throttle body that has never had the idle adjusted. What I don't know is if it's the stock TB from the D16Z6 or if it's from the JDM D16A. Not sure if the JDM D16A came with an FITV.

I think I will continue with the idea it's predominately all stock motor and getting my idle fixed.

Also read up that the idle relearn can take 250 miles or so to complete and since I literally just reset the ECU, it's no where near completing it's learning process and will still act a little off until it learns more. Being it's not idle hunting and just overshooting a little bit on decel, I think it's on it's way to relearning from a fresh reset.

I thank the feedback I have received so far as I am getting a much better insight on what to expect when looking at the idle systems over and beyond what is put into the FSM.

Cheers.

 

 

Based on Ron's reply, I started investigating and before I even got out the door, I found my FITV is not closed when the car is fully warmed up. The bottom hole is still sucking air after the fan kicks on multiple times.

I cannot set base idle successfully like that and so for the time being, I have the idle set screw for reduced idle to help compensate for the additional air it's getting from the FITV. The idle is a little smoother but still problematic, however it will have to do until I can get some KROIL to penetrate the FITV cover plate screws.

Once I can access the cover plate I can clean up the upper portion of the valve and tighten it bit by bit until it seals when warm, and then see if the idle stabilizes during the idle set procedure.

 

it isn't a bunch of goop, its a sort of rubber cap they put over the tb screw. have you adequately bled the coolant as well?

 

I believe so. I did the bleeder screw until nothing but coolant came out with the heater on full hot. And with the cap off, I ran it until the fan came on 3 times. I shut it off, retopped up the radiator, made sure the recovery was topped up. Then closed up the cap tight. Next morning I had to retop up the recovery as I usually do after a bleed. Hasn't even come near overheating once.

Do you believe multiple bleeds are required sometimes? I did drain a fair amount of coolant from the engine head, heater core and radiator during the swap.

The rubber coating over the screw looked precisely done and took a bit to scrape off and out of the flat tip part of the screw.

Also, reading the FSM on the FITV, is says if you feel air sucked into the bottom port the FITV is leaking. I don't feel air but I do get my finger or thumb sucked on if I cover the hole and it pops when I pull it off. However just holding it above or right next to I don't really notice air flow.

Then looking at a spare FITV I have floating around, I took the non coolant side apart and I do not see how it could possibly make an airtight seal by design. It's a plastic piece over a metal bubble and then the plastic piece sits on another plastic piece. Not rubbery at all so I do see mild air leakage happening at both the plastic to plastic junction and the plastic to metal (brass?) junction natively. I did tighten the plastic ring about a quarter turn and no significant change.

If I remember, I will pull my intake off in the morning and see if I can feel a significant air flow through the bottom port when it's cold in the morning.

I honestly don't think the FITV is leaking and is operating normally. The IACV acts normal when unplugged, the idle drops significantly.

Looking at the troubleshooting guide, rough idle points to IACV (EACV), Hoses and Connections and then ECU.

What bugs is when the engine is warm, and the IACV is unplugged, it doesn't matter how tight I tighten the idle control screw, the low RPM almost never gets into range of 420 and if it does the engine shakes significantly trying to run and begin bounce idling as if it's about to die at 400 range rpm so kicks it up to prevent stalling then falls back down to 400 range to repeat.

One thought I had is I did not change my O2 sensor and it's been in the collector for several years of the heavy oil burning engine. Wondering if it is having a bit more difficult time reading the AFR. Been thinking I should slap in my brand new Denso one I bought several years ago but never used.

Anyways, I've pretty much put the idle screw back to the location it was when I took the rubber covering off. The FITV has been tightened a quarter turn, and the relearn was started this morning.

Now I was thinking I should go through all the other systems the FSM talks about when you can't set the idle low enough. Next on the list after "setting idles speed" is to check the alternator signal.

I also was thinking maybe I was jumping the gun as the ECU had just been put into the car with the engine swap, so the idle had to relearn from scratch anyway. Everything probably was at factory settings and then I had to go and meddle with it.

 

fitv is mechanical, not electronic. if you've already tightened the screw inside of it, it should be good to go. in my experience, when the screw has backed out, the affected car will have a very high idle. when you attempt to cover the fitv hole, have you allowed the car to fully warm up? sounds like you've covered the coolant bleed, so long as it was done on a slight incline. since this was a recent swap, are you positive you have the throttle cable adjusted properly?

 

I don't have high idle. It's more a hard idle and a tiny bit of fluctuation. Was actually quite lopey like it had big massive cam in it originally. Now it's a bit more mild with the boolup blup blup blup boolup blup blup idle. Really like it's has a hard spot on running, then easy part, repeat. And yes, the bottom port is covered up and sucks on my finger or thumb nearly burning my tender little fingers as the fan has kicked on a few times. Which tells me the engine has good vacuum and can create suction through the smooth non air tight junctions of the FITV. Or at least that's the impression I get when I inspected the internals of the FITV closely.

The throttle cable has a little bit of slack. Not a whole lot, but enough that I hear the throttle plate hitting the throttle plate screw solidly every time without issue and the cable moves about 1/8-1/4 inch down when I push down on the cable without pulling the throttle plate at all or feeling tight. I actually had to loosen it for this motor as in it's original setting on the old motor it was overly tight (as seen by the clean spots on the threads where the bolts were).

I will also do the IACV tests. Just because it's working, doesn't mean it's working well.

 

:::Update:::

I was going to be putting off all the testing until after the weekend as I have to work this weekend too.

However, tonight when I went to get gas my alternator belt squealed something fierce. I get out after stopping the motor and sure enough it's pretty loose. So after I get gas and get back I loosened the top bolt and the alternator moved freely. I felt for the under bolt and nut and found just the empty hole.

Anyways, I stole the bottom bolt and nut from my old motor, and took the belt too as it's pretty new and now it's snugged up.

I suspect the alternator signal was erratic which could be the cause of the erratic idling and not being able to set base idle.

I will restart the idle learn in the morning and just let it do it's thing for the weekend as I'll be driving lots this weekend. I'll report back my findings.

Kind disappointed with myself for not noticing that during the swap process.

 

its always something like that. hopefully that takes care of it

 

I rebled it this morning. This time being sure I was on a solid incline with the nose up. I got several sizable air pockets out with 4 fans cycles before cinching down the cap.

My reservoir is going down, not up and I can't find a leak anywhere. The idle cleared up for the first part of the day but started getting erratic again by late afternoon/evening. I will swap out my cap in the morning and bleed again. I suspect I have air pockets again. Possibly boiling off but not overheating?

Will also see about renting (buying) the block tester from my local Canadian Tire. Supposedly they have one for rent now for about 40 bucks (and if I keep it, it's okay as it's the cost of replacement). They don't seem to sell it normally, go figure.

I don't see oil in the coolant or coolant in the oil so not really sure at this point. I also cleaned the IACV valve without disconnecting the coolant hoses with Throttle Body Cleaner. Didn't have a lot of time to spend on it so just did some basics. Oh also checked for vacuum leaks when the engine was cold and found none.

So yeah, the adventure continues. Oh and I was thinking about pulling my plugs (they used platinums and I just anti-siezed them and torqued them to 13 ft-lbs when I did the compression test) and putting in the v-power coppers. When I have them out I will inspect the piston tops again now that it's been driven a bit. At the time of compression test pre-sale, they were pretty black with carbon. If the coolant is getting in the cylinder and burning off, it should be a clean piston now.

 

Check the radiator before starting every time you have the engine completely cold. Make sure it is staying full to the top.

Valves set too tight will cause rough idling.

 

Thank you for this.

Fluid was right at the top of the filler neck when I cracked it this morning. Then it sprayed me pretty good with luke warm fluid when I cracked it after letting it sit for an hour or more after going and picking up the block tester then moving the car quickly to my inclined area just down the block form my house.

Tester fluid stayed blue even when I was grabbing the bubbles.

Also, reservoir was only down 2 inches this morning.

I suspect what I may have been witnessing is the coolant level drops with cap off when the thermostat opens and fan kicks on. Goes to just lower than the bottom of the filler neck. I am guessing it would snag a little air at that point and then spit it back out when the fluid raised above the bottom of the filler neck when the thermostat closed. I think this is where the bleeder funnel for radiators comes in handy. You can keep the fluid above the top of the radiator with it and prevent any air in from the neck area with the system open.

I am thinking after I do a day or two without the system being opened and just continually top up the reservoir, it should be okay. And being all the hoses are silicone, I believe I will have to top up the reservoir more regularly over the EPDM hoses.

Friday, I'm off during the day so I will check valve lash and start on all the other idling tests in the FSM.

Thanks again for the information on how to confirm the cap is operating normally. And for the heads up that a tight valve lash can cause a rough idle.

 

sounds like you found the problem with the air in the system, given as it idled well after your initial bleed. glad to see you went with the z6, it is literally better in every way than the b7. its the b18c of the d series world (lol)

 

Not sure.

Tonight, there was a couple of times it struggled to drop below 1K rpm when I let off the gas. I pop the throttle for a second and usually it will drop after that. Happened last night too. Just didn't get it my short drive this morning.

I think it will be good practice to go through all the tests as well as do the valve lash this Friday. Then I can also inspect the timing belt and take a peek at the water pump at the same time. And then I know the other issues of idle are ruled out via FSM tests.

I'm beginning to suspect I have the joyous intermittent IACV sticky problem. I don't like that idea as The Z6 IACV is not common parts in my area so it's going to cost me a few hundred new if it is the culprit.

Not sure why the B7 IACV is a TEC and the Z6 is a Denso. Both holes look to be the same diameter, but I suspect the stepper motor is configured differently for each. Sucks too being B7 IACV's are a dime a dozen here in the parts yards.

 

you're in luck, the b7 iacv works just fine on the z6.

 

I'd say, I have at least 5 B7 IACV's floating around in my parts boxes.

After I go through everything, I'll swap it with the one from my old B7 motor as it didn't have idle issues (cept when the throttle plate was sticking open).

Thanks for that. Save a pretty penny for sure.

 

no problem, ive been patching these motors up for a loooong time.

 

The FITV should pull zero air through the TB hole after engine is warmed up.

 

I honestly don't see how that is possible, unless the strength of the vacuum is near non existent. Single seam smooth hard plastic on smooth hard plastic is not an air tight junction nor is single seam smooth hard plastic on smooth metal. There is one of each of these kinds of junctions in the FITV Air Pathway. Without rubber sealing surfaces, you can easily blow air through these kinds of junctions. Not very much air but some air will seep through.

Not saying you are incorrect Ron, just that I don't see how that is possible by the design of the FITV.

 

If you can feel the pull, it's too much.