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Discussion Starter · #1 · (Edited)
A few weeks ago I removed my air intake pipe from the air filter box and I'm pretty sure this is when my car started ruff idling. The next day I also removed my engine wire harness and removed most of the hoses on each side of the air intake manifold as well as the fuel return line.

Last night I drove the car and noticed a bit of ruff idling when at 850 RPM. I thrashed the car and notice a couple of times that the car didn't have as much power, but most times it was fine.

Tonight I was doing the whole refill your coolant and wait for the cooling fans to come on shenanigans and my car was ruff idling on and off at 850 RPM. I then went to take it for a drive and it would stall as soon as I put it into gear most of the time. When I restarted it I sometimes even had to hold the key in start.

I'm almost certain this has to do with air intake. Perhaps its to do with a hose. I'm getting ECU code 14 which is related to the idle control system (EACV), and while I normally get that as our EACV's are unreliable, I normally get it after driving it and the engine check light comes on and this normally happens only if I am driving at 110 kilometres per hour or once every couple of months, but the ECU is throwing it right off the bat without the engine check light.

I'll have a look at the troubleshooting flow charts tomorrow and then the engine but I would others thoughts which may save me time.

Here are videos of the behaviour...

Ruff idling:



Stalling; restarting with key held on start, then accelerating at 100%:

 

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Discussion Starter · #4 ·
I’m having the same trouble with my car and I’m wondering if removing the EACV and cleaning it and reinstalling it would help?
If you are getting check engine light and code 14, pulling off the EACV and flooding it a few times with carburetor cleaner helps heaps from my experience.

Have fun getting the EACV off and afterwards see where they moved it on the 4th gen. :)


Now that I think about my problem, I think the code 14 was already their, induced by previously troubleshooting another problem.

I'm almost certain its a vacuum hose. Luckily I have a photo of the hoses taken right before I pulled them all off. I'm 200% I put them back on correctly but maybe I've missed one. We'll know tomorrow.
 

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Exactly the same thing. I just installed new distributer assy and no help. I think mine was there before as well. If you figure it out, please let me know what you find. It’s making me nuts.
I’ve been dreading pulling the EACV because it looks so hard to deal with the coolant hoses.
I already have a new o-ring.
Cheers
nigel
 

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Discussion Starter · #7 ·
Ok, so I think I found the problem.

One of the coolant lines going to the EACV from the back of the engine has ruptured. I took out my engine wire harness a few weeks ago and removed that hose with common pliers as I can't afford hose pliers. I knew I did some damage but thought I got away with it.

I didn't know the EACV takes coolant. This problem only happens after the car has warmed up so I'm guessing it happens after the thermostat has opened and allowed coolant to pass through and get to the EACV. I'm guessing the EACV monitors the engine temperature from the coolant and adjusts the air intake accordingly.

I also have an intermittent problem with my temperature readings. The temperature gauge shoots up to normal when turning on ignition, even when the engine is cold. It reports overheating correctly which is good but it still concerning and I'm hoping this problem is causing it, like air bubbles having gotten into the cooling system and messing with the pressure.

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Discussion Starter · #9 ·
The inner diameter is 7mm.

Why are there so many fucking dumb people in this world. More than 50% of people selling car hoses don't specify if the size is the fucking inner diameter or the actual size of the hose. Fuck! Is it that hard?!
 

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Thanks for the update. My temp reading is doing the same thing. Goes to running temp almost as soon as I start the car and sitting at a light it will go up like it’s overheating. The fan cools it back down. I replaced the thermostat thinking that was the problem. Maybe replacing the two coolant hoses that go the the EACV and giving it a good cleaning it while it‘s off will solve the problem but changing them is gonna be a bitch to get them off and new ones back on.
I have two 91 s and they are both doing the same thing. My other 91 has a big coolant leak that I can’t find.
Cheers
nigel
 

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Discussion Starter · #11 ·
You must clean your EACV's and you must find and fix your coolant leak. There are only so many hoses. You will need to trace them. You can go onto 'hondapartsnow.com' and view the diagram for the radiator and water pump to find out where all the hoses are.
 

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Discussion Starter · #14 ·
By the way, I noticed my car was blowing out a lot of smoke from the exaust tonight so I took a video of it, but I deleted it when cleaning up, so the scales are weighing more towards your problem being EACV related.

Don't worry. Carb cleaner will sort it out. Their a solid state device. They just need a good cleaning.
 

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I'm guessing the EACV monitors the engine temperature from the coolant and adjusts the air intake accordingly.
The coolant lines going to the EACV are for nothing more than heating up the valve in case its frozen for when the vehicle is in freezing climates. Same reason you have coolant lines going to your throttle body. They can all be bypassed and have no bearing on how the motor runs if you live in a climate that doesnt freeze often.

However, you also have a fast idle thermal valve (This is a pure mechanical valve generally bolted to the throttle body) that also has coolant lines going to it. Any air pocket introduced into the coolant system that reaches this valve can cause erratic idles. Most commonly the idle will surge up to 1500 rpm and down repeatedly, mimicking a vacuum leak when there is none.

First step is fix all coolant leaks, and thoroughly burp the coolant system. Then see if you still have idle issues.
 

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Thanks

You know I'm not even convinced it's the cause. The leak is so small. And also because I have trouble accelerating.
It may not be, but like I said, air pockets in the coolant system absolutely can cause idle issues. So fixing any leaks first is important so you can eliminate that scenario as a cause. Plus its a quick and easy fix
 

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The Fast Idle Valve wax deteriorates over time and they start the surging thing. All you can do is hope the tightening the inner plastic thing works They don't exist any more, new and the used ones, if you can find them, are usually already toast.
If anyone knows where to find them new, that will fir and work, that would help the whole 3rd gen world.

Cheers
nigel
 
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