mjshealy

Hello all, this is my 2nd post and first topic here.
I have a 1992 Honda civic lx (4dr, 1.5l D15b7), my daily driver, and i've had an ongoing idle problem for a couple months now. When i first start my car (cold)it jumps to about 3000 RPMs, then ever-so-slowly moves to 1200. Once it runs for a minute or two, the idle begins loping between 1,000 and 1,600. I have adjusted the idle screw all the way to the closed position, but it just makes it lope slower. When the car's under load (in Drive or Reverse), the idle doesn't lope, it stays at 1,000. When i have the AC on, in park, it does not lope either, but idles at 900 - 1,000. I have heard it could be either the IAC or the FITV, i will try to clean those and test them and get back here with the results. On a side note, and i dont know if this is a related problem, but the performance seems to be slightly bogged down, and the performance really varies. I could leave a stoplight and slam the gas 5 times, and each time it seems faster or slower than the time before. Sorry for my storybook post, but i wanted to give all available symptoms to help the diagnosis. I replaced the head gasket, intake gasket, exhaust gasket, and timing belt about 6 months ago, and have performed a PCV system bypass, so there is no PCV valve anymore. thanks in advance for any help.

ek-g6

I was going to suggest either the IACV or the FITV, but saw that were going to clean it. Have you check for vacuum leaks, at the TB, or intake manifold?

mjshealy

there are no leaks at the throttle body or the intake manifold. i have sprayed all vacuum lines with windex (i like it better because it bubbles up, and makes the motor die down) and i cannot find anything. I just cleaned the IAC and FITV after i made that post, and there was no difference at all after i cleaned the IAC, but it got slightly better after i cleaned the Fast Idle valve. The IAC is obviously still electronically working, because i cannot drive the car with it unplugged, it dies and kicks when i let off the gas. I had a big problem with the Throttle body gasket about 4 to 5 months ago...had to replace the intake manifold because the bolts that hold the injectors/fuel rail broke off after i replaced the injectors. So i went to advance, napa, autozone, pepboys, and the local dealership and they all brought me the wrong gasket.... it was completely different than mine, and all 5 places had the same gasket. the only other one was for the d16, which wouldn't mount up either. So i ended up getting a sheet of waterproof and heatproof Gasket sheeting, and made my own gasket out of the one that was on the manifold. I did everything precise, and it has worked thus far. i noticed on the inside of my throttle body there's 2 holes...one for the IAC and one for the FITV, the FITV has a small-to-medium amount of vacuum when i plug it with my thumb, but the IAC hole just about ripped skin off of my finger when i plugged it. I thought that might be a problem, but there's no CEL?

ek-g6

Did you just clean the holes of the Fitv or did you take it apart and clean it. I had the same thing happen when the fat white screw inside of the FITV came loose and made my idle go crazy. Heres a link on how to fix it and clean it.

https://honda-tech.com/forums/acura-integra-6/%2A%2A%2A-how-%2A%2A%2A-clean-your-fitv-aka-fast-idle-thermo-valve-1564019/

mjshealy

LMAO...i just read that tutorial 10 minutes after i made this topic. Yes, i stripped it all the way down. I seem to have a bit more power now, but the idle's still weird. I closed the white casing all the way like it said too. What do you think about the IAC hole in the TB? i can hear it whooshing air in like crazy, i think somehow it's getting too much air, but the IAC doesn't seem to be stuck open so i really don't know what else to do.

Former User

Did you do this test when the engine was hot or cold? You should feel vacuum from the FITV port ONLY when the engine has not fully warmed up. When the engine is hot, there should be no suction whatsoever from the FITV port.

Also, in what condition are your plugs, wires, cap, and rotor?

mjshealy

I'm sorry... I should have specified. When i first cranked it up after cleaning the two valves was when i checked those...the engine was still cold. But now, the FITV actually does close when the motor gets hot, whereas it didn't before.

Just changed the plugs 6,000 miles ago. The wires were new when i got the car in september, distributor looks like a junkyard one, "9158" written in white paint across the metal on distr.
All-in-all, i love the car. It's at 310,000 miles and it still runs like the day it was made, no noises, and not even a hint of backfire/misfire. I'd love to see it get farther than 310 though! lol

Former User

Can you describe the current idle problem since cleaning the IACV and FITV?

How do the contact points in the distributor cap and rotor look?

thi3v3z

Just to double check, when you checked spark plugs, did you gap them, or just look for discoloration?

mjshealy

contact points on the distributor and rotor look good, but cleaned them anyway. When i changed the plugs, i bought NGK plugs pre-gapped, but i checked them anyway because i'm OCD like that.

Thanks for helping guys, i know you're going out of your way to help, and i appreciate it.

The current idle situation is about the same...like i said it's a tad bit better and now it just lopes slower (as in takes less time to shoot between 1000 and 1600)

needless to say, im stumped.

Former User

Have you thoroughly and correctly bled the cooling system?

mjshealy

hmmm...the last time i did that was when i changed my head gasket. it was quite a few months ago. Coolant in reservoir and radiator is still full, but i will check first thing in the morning and post up. would that cause it to idle & lope that high though? i understand that would make it lope, but that high in RPM's?

thi3v3z

double check the throttle cable to make sure its not sticking or binding, when you replaced your head gasket, you may have set it somewhere or moved it and caused a kink.

Former User

Yeah, air trapped in the cooling system could cause an idle problem like yours.

Bleeding the cooling system:

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):



----------------------------

When done, next check the throttle cable adjustment as mentioned and then also adjust the idle speed as described below:

mjshealy

i checked and adjusted the throttle cable, no kinks that i can see anywhere. I was brainstorming the last week or so, and i've checked all that i know to check. I checked the coolant level, the oil, IAC, FITV, Throttle body and vacuum lines for leaks, pulled the spark plugs again to make sure they're fine, grabbed plug wires to make sure one isn't fouled (lol), checked for arc against ground with plug wires, checked EVAP canister for leaks, and checked coolant lines for leaks. Should've listed this before...my apologies

mjshealy

i will bleed the cooling system tomorrow, but cannot do anything with idle speed as i cannot get it below 1,000 RPM's, and that's only when its loping, thats as low as it goes. the idle adjustment screw is tightened all the way, it cannot go any farther.

Former User

Note that the correct idle adjustment procedure is done with the IACV (EACV) connector unplugged (see diagram). This will significantly lower the idle speed. In addition, if bleeding of the cooling system eliminates the hunting idle, then you may be able to get the idle speed adjusted without interference from fluctuating idle speeds.

mjshealy

isn't the idle speed supposed to be like 460 with IAC unplugged? i'm in the process of bleeding now, the fan has engaged twice, but i'm going a tad longer to make sure. The Idle is NOT loping anymore! However, sadly, the idle rests at 1000 warm now. i will try to unplug the IAC and set idle speed now, will post up when finished. Thank you guys for your help thus far! it's greatly appreciated!

Former User

Sounds like promising progress. With the IACV unplugged, the idle speed should be adjusted to 420 rpm +/- 50 rpm (see diagram).

thi3v3z

1000 is a little high might need to be adjusted by the idle screw or also make sure that the throttle cable isnt too tight and holding the throttle open slightly causing a higher rpm. But if it is fixed, congrats

mjshealy

IT'S FIXED!!! i just drove it for 30 minutes to make sure, and it's idling perfectly now. THANK YOU both for all of your help! i'm usually pretty good with cars, but this one stumped me. I appreciate it ALOT guys! Ron, you're the man!