1993 accord 2.2 idle surging, cleaned IACV, FITV,etc

[mrb455]

I picked up a 1993 accord 2.2, for my daughter last week and the idle was around 100-200rpm ,,,,I have cleaned and adjusted the IACV, FITV and TB (replaced the gasket as well),the EGR plugs are new and seem to have been removed and replaced, I assume that the ports were cleaned. I also have checked for vacuum leaks w/carb cleaner over every vac source including the intake. Topped off and burped the cooling system, unplugged the IACV while running and the idle drops but surges quickly only rising 100-200 rpm.


Still have the surging idle after cleaning TB, IACV, FIV, EGR ports and the EGR, someone said to pinch off the TB vac line and see if it dies, I pinched off the TB vac line and it did die. Is that important? I decided to order another IACV (off eBay, cheap) and it should be here in a couple of days, I hope it works. I cant find any vac leaks, sprayed C Cleaner everywhere with no change. Checked ABV and is good, it dies when I pinch off the vac line on the TB, I am still waiting to find out if that means anything.

[ON_N20]

Hello and welcome to the forum. Its nice to see someone who can type great for a first post

Which vacuum line did you pinch off that made it die? If it was one of the vacuum lines leading to the black box that contains the MAP sensor, and you pinched that line, it very well could die from that anyway.

I read your post, it sounds like you covered the bases quite well. In hondas though a surging idle almost always is a vacuum leak. Our engines are speed-density based, so they calculate air flow based off the MAP sensor, TPS, etc. If the MAP sensor reads more air flow (from a vacuum leak), the rpm's will increase, but since its at idle, the TPS is minimal. As the RPM's rise with very little load, essentially what the computer thinks its seeing is a decceleration. In response as a fuel saving feature, it cuts the injectors and the idle drops. As it drops low, the cylcle starts again. This is where Hondas get the surging idle.

Are you sure the FITV is adjusted correctly? There is a white plastic screw adjustment internal to it that can back out, and cause an excessive vacuum leak. There are a few great videos on Youtube regarding this.

I see you also checked the ABV (air boost valve) already, but maybe remove it and temporarily plug it off. The valve should be open while the engine is off, and shuts with vacuum. If its sticking while the engine runs, it could cause a vacuum leak there.

Also check the large vacuum line leading to the brake booster. You could also temporarily block that off too make sure there is not an issue there causing a fast vacuum leak.

Good luck

[mrb455]

I adj FIAV down @ 1 1/2 turns with no affect, I blocked off the ABV and also no difference...The vac line I pinched was the one on the TB that went to a box on the firewall which I opened and saw all the lines going to a circular object that had several lines going to and coming from it.

[reklipz]

I picked up a 1993 accord 2.2, for my daughter last week and the idle was around 100-200rpm

Just for clarity, you're aware that there are no hash markings on the dash for RPMs lower than 500, correct? I made this mistake the first time while working on these components and it really threw me for a loop.

Topped off and burped the cooling system, unplugged the IACV while running and the idle drops but surges quickly only rising 100-200 rpm.

You should have gotten a code 14 from the ECU when you unplugged the EACV; did you? Also, you can verify that the motor inside the EACV is still good with a simple ohmmeter, it should read somewhere around 13 ohms.

[10thAnnivCB7]

Not adjusting the FITV at the right temperature will give you the wrong idle when the car actually warms up. Small vacuum leaks also add to this problem.

[mrb455]

I wasn't aware the temp had to be right before adj the FIAV, I am assuming it has to be warmed up.

[wildBill83]

Have you seen this thread:
http://www.cb7tuner.com/vbb/showthread.php?t=53161

and this thread:
http://www.cb7tuner.com/vbb/showthread.php?t=146239

[mrb455]

Yes,, great post! Tried all mentioned w/ no success.

[kountrymike]

Just as a second set of eyes. I had this issue and it was the 2 lines that are on the back of the manifold. They are on the drivers side against the firewall and are used by automatics for the motor mount. They are hidden back there and it might be something you over looked. I have a manual and I ran them into one another. Other than that it sort of sound like it might be a bad part. Good luck hunting.

[Raf99]

Soooo nice to see a newbie do research first and try stuff. *shakes hand.
Maybe you could upload a video for us of your rpm action? I have the same issue and mine is quite severe, jumping from 500-1500rpm in a constant loop. But others are a mild change in rpm.

[reklipz]

The ubiquitous bouncing/surging idle between normal idle and 1200-1400 RPM is due to the FITV. I would start by replacing that part before any of the other valves.

[Sloweredcb7]

Mine does the same but it goes from about 1100-4000 idk I've cleaned the eacv the fitv and don't know where to go next

[oni_cb7]

Mine does the same but it goes from about 1100-4000 idk I've cleaned the eacv the fitv and don't know where to go next

Holy thread bump Batman!

Try not to resurrect a 4 year old thread.

However, make sure your Idle Screw is adjusted correctly. This is usually the case when all else fails.