Just bought this car for $750 from this guy who obviously didn't take care of it. Had to basically replace all the stuff that should be replaced regularly (and wasn't) ie. wiper blades, oil, air filter, plugs/wires etc.

I have read over and over across the interwebs about this problem.

The problem that I have is when it's in neutral (5 Speed) the engine idle bounces from 1000-1500. Constantly. Under load, I obviously don't see any RPM issues, but it's driving my insane.

SO the answers for the issue I having that I have seen have been:

IACV
FITV
Throttle position sensor
Intake Manifold gasket replacement
Vacuum Leak
Top Dead Center sensor
Low Coolant
Air in Coolant line.

I replaced the IACV, the FTV, I THINK I bled the coolant system (burped it, since my car doesn't have a bleed valve i can find), changed heater hoses, made sure coolant was full. I am still having this issue, and I need to know what I should do to fix it.

PLEASE HELP!!

Thank you!

Jimmy

 

an internal or external vacuum leak is the cause. ecu sensing too much air past the throttle plate and cutting the injectors in an attempt to lower the raised idle speed.


listen for a sucking/whistling sound. if you hear one try to pinpoint it and determine if it's an air leak.

look for disconnected or cracked vacuum lines - open vacuum ports

spray water very lightly misting around any gasket or hose that would be under a vacuum, and listen for the idle to change. being careful what you spray it on.

remove intake piping (leaving any sensors/senders connected) and restrict airflow to the bottom bypass hole(for FITV) in the throttle body inlet. there should be no air traveling through this passage when engine is at operating temp.

ensure throttle plate is in proper idle position -throttle stop screw/cable not sticking or too tight

you can also attempt to adjust the idle screw per fsm instructions - although it's doubtful this is out of spec - unless it has been tampered with before.

any MIL codes? front end of car jacked up when coolant was bled?

hope this helps,
silky

 

Silky,

I will check that out. The surge is going to give me a complex, and it's pretty embarassing as it is to not only be in a multi colored accord, but one that can't stay at a constant idle....

I did see a video about some other sensor mounted on the driver's side of the injectors and the guy called it a "Japanese Annoyance Device". Also known as an Air Boast Valve. He said to "Shim" it with a piece of aluminum and it would fix the problem. I did this, to no avail.

I went to the Auto Zone, and the guy sprayed WD40 around, and the engine didn't respond at all, so maybe an internal leak? Manifold Gaskets? I have no idea.

It has to have a solution somewhere, cause I'm sure it didn't do it when it rolled off the line in '91. But after replacing the IACV for 300 bucks, the FITV for 100 bucks, new hoses, etc.... I'm already like 600 into this thing.

Any further help is greatly appreciated.

Thanks,

J

 

understandable - i have talked to people at stop lights who have a honda/acura with a surging idle, trying to help them out lol. it's very common where I live , so I wouldn't feel too embarrassed.

internal leak would be FITV - IACV - throttle plate/cable/screw mis-adjusted - idle set screw out of spec - external leak would be hoses - gaskets - open ports

i believe he was referring to the fuel pressure regulator diaphragm. if it's leaking vacuum it can cause this problem directly. if it's leaking fuel - it will make your engine run rich. potentially indirectly causing ecu to sense too rich of a condition (would be theoretically the same as o2 sensor reading sloppy/full rich often) and possibly cutting injector pulse/opening closing IACV constantly.

but for the most part, an fpr leaking on the fuel side will cause a sloppy idle - not a surging one . I want to say I have heard of a leak on the fuel side of an fpr diaphragm causing a surging idle, but I can't be certain - and I have never personally had that cause for surging idle. in one form or another, a vacuum leak has always been the cause for me.


i would check for leaks the same way yourself, along with the other things i mentioned. not that i don't have 100% trust in Autozone lol, I would just feel better testing it myself.

 

Where the lower hose connects to the engine, also where the t-stat is.....there is a bleeder screw, just like the brakes.

To bleed the system, my way and has NEVER let me down. Set the heat to max heat - opens the heater control valve.....some of the newer gen's (6th ? and up you need to turn the key to on/pos II as the valve/cable is driven by an elect motor). Remove cap and SLOWLY add coolant until a steady stream comes out the bleeder. Close bleeder.

Replace the rad cap to THE FIRST CLICK only. Start the car and let it run until the cooling fans cycle at least once - depending on outside temps this could take 15~30 minutes. Then shut the car off. Remove rad cap _WARNING_ the reason for ONE click on the cap was so no pressure builds in the system....your risk. Top off rad and overflow. Replace cap, all they way this time....and see what you have.

Sorry, "silky" but IMHO I don't think you are giving the correct advise to the op....but that is me, this is a fourm and we all have our opinions.

 

problem was solved. idle set/air mix screw was too far out/rebuilt fitv was also out of adjustment.

not saying air in the coolant system couldn't be a probable cause, but an internal/external vacuum leak has always been the cause of surging in any car I've got my hands on, and I can't recall hearing otherwise from anyone else.


never heard of using a cap during bleeding procedure - first click?

I've always bled from screw, if available, then squeezed rad/heater lines until i saw no bubbles in radiator, myself. heat on - blower on, of course.

 

Are you the OP ?

 

Nope, but I can call and ask him to chime in later today, if you'd like?

 

I'm just trying to figure out how it went from the OP asking a question to you saying the problem was solved.

 

Hey guys. I did originally ask the question about the Honda. Silky jumped right on it. We linked up and he guided me through adjusting the idle set screw on the TB. First had to unplug the sensor on the IACV, started the car, idle was a little rough. Grabbed a flat head and turned the idle set screw in until it started to idle at around 800. Stopped the car, plugged the sensor back in, and Silky warned that the check engine light may stay on. Fortunately, it did not. Cranked the car up, and it purred like a kitten with no surge.

Sorry about the delay in response, but as Silky knows, I am in the military, and just got access to the posts. But he knows his sh*t. :-)

Thanks again, SilkyPillows. Car is still running like a champ. I hope this helps anyone else with the annoying surge issues.

Have a great day!

 

 

Shimming! Is my next try. The airboost, or part ppl usually block - off was a Great help 4 my F2a1 90LX. The plastic ring you' ll find , was tightened all the way down. I used my finger to touch spring- loaded bobber¿ to let air in to find theory behind Donkey. Yes , idle reminded me of Donkey (cold) he aaw he- aaw, tighening work, but cable is adjusted low. Too low, engine dies. So thanks 4 post. This one, I'm working on too.