Rough Idle Occasionally [Archive] - 3geez.com - Classic Honda Accord & Prelude Forum

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hondatech26

08-15-2013, 10:00 AM

So I've been trying to work at this idling issue for a few weeks now. Reading up on other posts before suggest that I need to adjust my FITV by turning the tuning screw until tight (not too tight). Then I'm supposed to clean the IACV, but I can't seem to get an easy access and clean this part.

I also called a local mechanic shop testing the waters on having them so the part, and well they suggest that the IACV isn't repairable (cleaned and reinstalled) and it will have to be replaced.

Two questions: How do I access the IACV to clean it?
Is he right? I have to get the IACV replaced?

Here's some pictures:
My Engine Bay
5372

The IACV
5373

The FITV (behind the TB)
5374

My issues (fuel rail or some kind of railing blocks the bottom left bolt):
5375
5376

Jafir

08-15-2013, 01:15 PM

Assuming that the idle doesn't drop too low, the IACV isn't going to cause a rough idle. Does the idle stay put when turning on the a/c or rear defroster while in gear, etc? Most causes of rough idle are tune up issue... plugs, wires, cap, rotor, timing, idle speed, valve adjustments etc. I've also seen leaky injectors and bad o2 sensors cause the idle to be rough. There used to be a problem with the PCV valve coming apart inside and the engine would idle rough and consume too much oil, but I assume most of these valves have already been replaced at this point.

I've also seen the idle feel rough, even with the engine was running fine because of motor mount issues.

Jafir

08-15-2013, 01:17 PM

Also, those tubes in the way are vacuum lines. You should be able to unbolt them and flex them out of the way.

hondatech26

08-15-2013, 01:28 PM

At some point in time there it would be an instant idling issue whenever I turned my car on and it would struggle and die. But the current issue is that when I start it up in the morning (most often occurs at this time) it will idle between 800 and jump up to and at max 2000rpm. Mine is a 5speed, so even when I pull up to a stop light, it will jump up and down only in neutral, but never while in gear.

I'm in the need of doing a tune up pretty soon here, so that could possibly erase this issue. In reply to your suggestions, I'm quite a newbie to this portion: "timing, idle speed, valve adjustments etc". I've replaced my timing belt less than 10K miles ago, but where will I be working with the idle speed and valve adjustments?

I recently purchased a PCV valve replacement just in case, but trying to go about this assembly is confusing because the diagram I found shows it being a tube - I found the tube much like a hose with a rubber cushion around it, but my part replacement isn't tubing its a small piece about the size of an eraser or so.

hondatech26

08-15-2013, 01:29 PM

Also, those tubes in the way are vacuum lines. You should be able to unbolt them and flex them out of the way.

I tried, and the tubes are metal so not much flex available..

Jafir

08-15-2013, 03:16 PM

hondatech26

08-15-2013, 03:21 PM

Low coolant is the number one cause of the surging you describe. Also if the idle adjust screw is too loose. I've seen them just back themselves all the way out. I use hondabond over the top of the screw to hold it in place. Finally the fast idle valve. If your adjustments didn't fix it, you might have to replace it. Other vacuum leaks could cause surging too, but they are pretty rare.

I'm going to do a full flush of my coolant since its been over a year since it was done last. I'll let you know how that works out for the idling. Thanks for the help!

onebad4D

08-15-2013, 06:49 PM

when I pull up to a stop light, it will jump up and down only in neutral, but never while in gear.

Are you saying the engine rpm oscillates? I had this problem until my EACV died completely. After I replaced the EACV, it solved the engine rpm oscillation, as well as an annoying long-standing idle vibration issue. The EACV is expensive. I found one off of a 1990 Prelude in a junkyard for about $5. The gasket I used was Honda Part Number: 36455-PT3-A01

hondatech26

08-15-2013, 10:21 PM

What's the EACV? Is there a difference between the EACV and IACV (Idle Air Control Valve)?

I could look at my local junk yard to try and find one if I need to, but if those parts are the same then it was hard enough to try and access it when I attempted the other day. It's stubborn!

import racer

08-16-2013, 05:26 PM

There should be a couple of bolts that hold the metal lines in place.remove those and u should get enough movement to unbolt the eacv and try to clean it.the eacv and iacv are the same thing.

hondatech26

08-16-2013, 11:56 PM

There should be a couple of bolts that hold the metal lines in place.remove those and u should get enough movement to unbolt the eacv and try to clean it.the eacv and iacv are the same thing.

So I tried that but I can only get it so far without needing to actually pull it up and out of the way. The bolt was so close, less than a 3cms but at that point it was rammed against the metal lines..

Oldblueaccord

08-17-2013, 08:09 AM

Bleed the coolant with the bleeder by the t stat then you might have to loosen the coolant lines on the eacv (iacv) and bleed air out there. Youll hear air escape when you pull on the hoses.

Fast idle valve is for cold fast idle. It only mess,s with the hot idle if its leaking vacuum.

Running the base idle hot around 900 to 1000 is just fine.

These cars dont idle perfect like A V 8 does.

Dr_Snooz

08-18-2013, 08:26 PM

So I tried that but I can only get it so far without needing to actually pull it up and out of the way. The bolt was so close, less than a 3cms but at that point it was rammed against the metal lines..

It should be held in place with three bolts. It takes some doing, but you should be able to manage it. You might have to pull some other stuff off too.

hondatech26

08-26-2013, 08:02 AM

So I've recently flushed my coolant with the Prestone flush fluid, and did an oil change. The idling has gone away, but now I have a funny starting issue.

It doesn't always happen, but at times my car has a rough start. It's hard to describe but it goes like this...

I turn it over to start, after letting the car sit in accessory for a moment. Then as it is turned the rpm jumps to about 3K two to three times with the interior lights flickering and the engine sounding like it's choking. I let ago (not liking the sound) and then turn it over for a second time and it starts up perfectly.

PS Sorry it took so long to reply!

HLW

08-26-2013, 10:35 PM

It doesn't always happen, but at times my car has a rough start. It's hard to describe but it goes like this...

I turn it over to start, after letting the car sit in accessory for a moment. Then as it is turned the rpm jumps to about 3K two to three times with the interior lights flickering and the engine sounding like it's choking. I let ago (not liking the sound) and then turn it over for a second time and it starts up perfectly.

Instead of letting it sit on accessory, let it sit in the run position to run the fuel pump for a couple of seconds. Then start it.

Most of the interior lights should be off unless you have the headlights on. If the head lights are on, they can keep the starter from getting enough power to start the motor easily.

If the headlights are off and you have a hard time starting after leaving the ignition on for a couple of seconds before starting, check the ground wires between the body, engine and transmission.

HelpMeHonda

08-27-2013, 08:01 AM

hondatech26

08-28-2013, 09:33 AM

I had a car once with a lot of the problems you describe and everything worked itself out when I changed the battery, I think it was the wrong one/was going bad and was causing my car to surge and struggle to stay on.

P.s. could also be the starter or alternator as well, it's hard to separate issues with the powering system components.

How to test your starter:

How To Test Your Car Starter - YouTube (http://www.youtube.com/watch?v=9PWG6Il_ZJI)

Alternator:

Diagnosing Alternator Problems - EricTheCarGuy - YouTube (http://www.youtube.com/watch?v=FTGz0PKIl84)

Battery:

How to Check a Car Battery with a Multimeter and Load Tester - YouTube (http://www.youtube.com/watch?v=r6_0-wfj8O8)

Hey so I actually just went to the local auto store the other day and they tested my battery which she said passed with 100% charge. She also mentioned that it could be the alternator slowly making it's way out, but she mentioned that if I took it out, that it could be recharged?

NEW EPISODE:
Last night I went to the store after work. I drove about a mile from work to the store. I go in, I get out and I start my car. While starting it, it had the issue I had mentioned of a rough cranking start. I let the ignition go, and started it on the second try without a problem like always.
This morning I turn on my car to run an errand, and it works perfectly. Driving, I come to stop at a few stop lights and what do you know, my idling problem comes back...I continue to finish my errand. Go to turn it on again after driving for about 3-4 miles. Another rough start, but this time I have video coverage! Where and how do I post this video of the rough start?

PS Recent work done:
Complete oil change
Coolant flush and replace

hondatech26

08-28-2013, 10:07 AM

conozo

08-28-2013, 12:36 PM

If you had your dome light on, what does it do when you try to start it when its doing the weird thing. Is it flickering or just dimming slightly and steadily while the starter is turning.

hondatech26

08-28-2013, 02:14 PM

If you had your dome light on, what does it do when you try to start it when its doing the weird thing. Is it flickering or just dimming slightly and steadily while the starter is turning.

My dome light?
The video I posted is exactly what happens when turning the key over, hope it's descriptive enough.

zenapup

08-28-2013, 02:28 PM

Well, you're battery light is not coming on so you may have an electrical problem, may just be a burnt out bulb. I also notice that the tach is jumping around on the first try, so the crank sensor could be going bad. My guess would be something related to the starter, as it works sometimes, but other times not. However, it could be something mechanically defective in the engine internally.

zenapup

08-28-2013, 02:56 PM

To me, it sounds like something is restricted when it it choking out as you call it, maybe have someone check to see if they feel air coming out of the exhaust when this happens, could be a stuck or barely bent valve, maybe also valve timing. Overall, it's weird that it starts perfectly the second time, making it difficult to diagnose.

conozo

08-29-2013, 05:55 AM

My dome light?
The video I posted is exactly what happens when turning the key over, hope it's descriptive enough.

I asked about the dome light because if its completely going out when starting it, then its most likely something electrical where the car is completely draining all the current trying to start. And i notice that your dash lights were getting abnormally dim but i couldn't tell exactly.

As Zenapup mentioned, you need to get that battery light fixed, it should be on with the other lights until the engine is running. Maybe you could temporarily switch it out with the low fuel light/cruise light to help you fix this issue.

I doubt that its an engine problem since your car starts and runs fine the second time.

Dr_Snooz

08-29-2013, 06:44 PM

Replace your ICM.

hondatech26

08-29-2013, 10:59 PM

I asked about the dome light because if its completely going out when starting it, then its most likely something electrical where the car is completely draining all the current trying to start. And i notice that your dash lights were getting abnormally dim but i couldn't tell exactly.

As Zenapup mentioned, you need to get that battery light fixed, it should be on with the other lights until the engine is running. Maybe you could temporarily switch it out with the low fuel light/cruise light to help you fix this issue.

I doubt that its an engine problem since your car starts and runs fine the second time.

Sorry for the noob question but what's the dome light?

It actually lights up sometimes when the car is in accessories, but like you had mentioned it doesn't do it all the time clearly. Any ideas there? Still sounds like an electrical issue.

Replace your ICM.

What's the ICM?

To add to this all, after cutting my engine and sitting in my car after a 30 mile drive today, I noticed my car making noises as it was off. I opened the hood and for about 5 minutes I heard like bubbling, tubing next to the battery area and a small wheezing coming from the radiator opening.

Dr_Snooz

08-30-2013, 07:48 PM

Dr_Snooz

08-30-2013, 07:54 PM

No wait. Better yet, test it with the test described on p. 24-9 of the 1986-89 Accord Master Manual available here: Honda service manuals - The 3geez Wiki
(http://3geez.wiki-tv.com/Honda_service_manuals)
It looks like an intermittent issue though. I would replace it either way.

hondatech26

08-31-2013, 12:24 AM

The tach hop is caused by a failing Ignition Control Module. It controls the spark to your engine and can cause the symptoms you describe. If it gets bad enough, it will leave you stranded. Replace it.

You really think it's that? That part definitely doesn't look cheap, and I'd want to replace it myself to cut some costs if possible.
I really don't want to get stranded some place though..

Also, any recommended places to get it? Maybe even a part number? I came across multiple looking parts with that ICM name :/

Jafir

08-31-2013, 01:48 AM

You really think it's that? That part definitely doesn't look cheap, and I'd want to replace it myself to cut some costs if possible.
I really don't want to get stranded some place though..

Also, any recommended places to get it? Maybe even a part number? I came across multiple looking parts with that ICM name :/

The igniters on the TEC distributors don't go bad very often. I'd probably look for a used one, maybe off of a bad distributor, if I were trying to save money. On 4th gen (which have many more problems with the modules and distributors in general) I have had bad problems with aftermarket parts. The last one was on my mom's 92 wagon. I stole the module out of a locked distributor in the junk pile and problem solved.

Oldblueaccord

08-31-2013, 07:22 AM

hondatech26

08-31-2013, 10:14 AM

The igniters on the TEC distributors don't go bad very often. I'd probably look for a used one, maybe off of a bad distributor, if I were trying to save money. On 4th gen (which have many more problems with the modules and distributors in general) I have had bad problems with aftermarket parts. The last one was on my mom's 92 wagon. I stole the module out of a locked distributor in the junk pile and problem solved.

I'd go and grab one from the junk yard, but should I at all be worried that the one I grab could be bad as well?

Ok well great video. 2 things to critque is kill the disco music and you didnt show the temp guage.

I would like to know if the car is real hot when your starting it. To me it sounds like the starter is pulling alot of amps dragging and your noticing the lights diming etc. If you can get someone to test the battery voltage at rest ,running, and the amp draw of the starter that really help. Little stuff like mpg and codes off the ecu help to.

Easy thing to try is make sure you battery terminals are tight,clean on the post. Try to twist them off by hand is the test. Check the ground wire from thd valve cover to the frame. Check your wire connections at the starter it self. The small wire is the start wire pull it and look for corrosion.

Haha I made so many test videos and it just so happened that this was the one that showed my problem, so I apologize for the radio tunes and not having the temp gauge visible.

The car isn't exactly hot when I start it, but it definitely is warmed up and that's when it most often occurs. Also I had the battery and starter tested at a auto parts store the other day and the lady said they were both running fine. 100% charge, no sign of starting issue.

Last night I had an incident where I was starting the car and it felt as if it wouldn't start as I turned it over. Starter was clicking. It started briefly with a woosh of air and died. Tried it the second time and again it worked perfectly.

Oldblueaccord

08-31-2013, 10:44 AM

another thing that can go wrong is the ignition switch. Usually the lights on the dash wont light up when you turn the key and you get a "no start" which to me is no cranking nothing.

Starter clicking is bad connections, starter or battery.

Check that stuff I listed it easy/cheap just time and some eyeballs. maybe switch batteries with another running car.

Could have that parts place check it when your starting it. If the voltage drops a lot it wont start.

hondatech26

09-03-2013, 02:46 PM

Here is my rough idle video
http://youtu.be/veBBwQIpfSQ