93 Accord Idle Goes Up And Down

[cb786]

watsup cb7 i have this weird idle,it goes up and down and when i put it in drive it idle at about 1100-1200 i have no clue what the problem is.the problem started today when i got back from mohegan sun and its auto with 176xxx miles

[jdmstylz24]

If the idle is rising and falling try replacing your PCV valve, these problems seem to happen often. Thats what was happining to mine, and i replaced it for a few bucks and car ran fine.

[cb786]

i replace that already still doing the same

[Johnz826]

It's ur IAC sensor. It controls ur rpm at idle. Prolly jus needs to be cleaned out. research where it's located pull it off and clean it wit some brake cleaner.

[cb786]

clean that already still the same

[19dabeast85]

Never heard of the PCV or IAC causing an erratic idle but okay.

95% of the time these symptoms mean your FITV located on the right front of your intake plenum is worn out. You can remove it and clean it as well as take it apart(3 screws) CAREFULLY and tighten the plastic nut inside to being just firm.

After doing that set your base ignition timing and base idle (howto found in either diy or tech sections) and see how it idles. If it's still acting up you'll need to replace the valve.

[cb786]

i tighten that already still the same but how do i set my base idle

[Johnz826]

i tighten that already still the same but how do i set my base idle

Replace the IAC sensor. Give that a shot. Curious, how many miles r on the motor?

[Johnz826]

Not to mention u may have a big vacum leak that can be causing an erratic idle.

[19dabeast85]

i tighten that already still the same but how do i set my base idle

Search for threads started by hondafan81 and put "base" as a thread topic only search term.

Replace the IAC sensor. Give that a shot. Curious, how many miles r on the motor?

While possible, it's unlikely the IAC is causing this specific issue. The FITV goes bad much more often than the IAC. The OP has better chances of fixing the problem by replacing the FITV than the IAC. Usually when the IAC goes bad it just become stuck in one position causing a low or high idle.

What's happening here is the FITV is malfunctioning allowing too much air in. The ECU detects this and turns the IAC way down. This drop in idle causes the FITV to close further dropping idle. The ecu detects this and adjusts the IAC way up to compensate. The process repeats over and over.

[DunKrS]

My idle was also jumping around erratically, at least until my car got warm. I took my FITV apart and it was spotless inside I was expecting it to be filthy, after that I decided to take the coolant nipples off the bottom (3 more screws) and checked it out, it was full of nasty, and one of the two passages was completely blocked, I cleaned it, and it hasn't given me issue since, maybe not the same problem as yours, but something to consider in case you didn't take your fitv that far apart, Good luck!

[Johnz826]

I took my FITV apart and it was spotless inside and my idle was also jumping around erratically, at least until warm. after that I took the coolant nipples off the bottom (3 more screws) and checked it out, it was full of nasty, and one of the two passages was completely blocked, I cleaned it, and it hasn't given me issue since!

Huh, i learned sometin new. Thanks for the info bro.

[DunKrS]

Huh, i learned sometin new. Thanks for the info bro.

You're welcome, I'm glad I can contribute to this massive cache of information! There's so much helpful stuff around here!

[Johnz826]

You're welcome, I'm glad I can contribute to this massive cache of information! There's so much helpful stuff around here!

yea dude this is the only place i go for any accord info or how to knowledge.

[saqi44]

Sorry to interept,the same problem was with my CB7, but when i changed the ECU (bought for 3$ only), the idle speed went fine,,, though the ECU was a bit water damaged from one side