'88 LX-i Idle Problems (yes... another one)

[88cool]

Gents,

I'm in a pickle. Like so many other ppl my Accord isn't idling correctly. I'd like the opinion of those who have solved this problem before. And yes I have searched, I'm hoping for some insight/opinions. Here goes:

The A20 idles between 1200 and 1500 rpm when it's nice and hot.

The Fast Idle Air Valve has been replaced (5yrs ago??) the internals are bright and clean and the threaded in disc is bottomed out over the plunger. I took off the cover of the FIAV and watched/felt for any movement of the plunger while the engine was idling funny. There was no movement at all.

The Idle Air Control Valve has been replaced [(5yrs???) the inspection stamp on the unit indicates a production date of 2005]

A test of the IACV was performed IAW this procedure: http://www.ehow.com/how_5560848_chec...rol-valve.html

The test produced an ohm reading of zero and the unit was cleaned with electrical parts cleaner.

After driving to heat the engine up again, the problem persisted. When I switch on the A/C the idle problem goes away. The IACV opens up the allow the engine to compensate for the increased load, which tells me that is does function in some capacity. (?)
When I unplug the IACV the erratic idle continues for a bit then calms down to a normal, if not a bit low, idle.

No codes or SES lights through out this process.

So, what do ya'll think:
Should I plunk down the $187 for a new IACV?
Take the car to a dealer and pay out the nose and let them figure it out?
Drive it anyway, turn up the radio and forget about it?

[Dr_Snooz]

Vacuum leak or low coolant. If the coolant is low, you will need to fill and bleed the system properly.

[charliekuney]

I'd bet on a leak. My car went dry all the time and it never affected the idle, but a pin-prick in a line...

[88cool]

What is your best method for finding a vacuum leak?

I have heard a few horror stories about using a rag soaked in starting fluid and wiping it over the vac lines while the car is running. I guess you would listen for an increase in engine speed, or the sound of an ambulance comming to take you to the nearest burn unit?

[-$MOKIN-]

low coolent.....im a re re . i checked everything but that

[charliekuney]

Just...watch for it? They're usually not too hard to find. My car has had four in the past six months, and they were all fairly obvious.

[stephensimmons]

You could use carb cleaner.

[Dr_Snooz]

What is your best method for finding a vacuum leak?

I have heard a few horror stories about using a rag soaked in starting fluid and wiping it over the vac lines while the car is running. I guess you would listen for an increase in engine speed, or the sound of an ambulance comming to take you to the nearest burn unit?

Sheez. About the only real way is dogged persistence and a lot of luck. They can be buggers to find. I had the mother of all vacuum leaks and couldn't find the blasted thing till it started hissing at me one day. Turned out my intake manifold gasket looked like this:



Use carb cleaner or MAF cleaner is also supposed to work. I'd avoid soaking rags with it. Just spray it on the likeliest leak spots and stand back a little bit. And avoid obvious ignition sources. The cat isn't going to have any vacuum leaks, so don't spray on that. Ditto the exhaust manifold or the alternator.

[gp02a0083]

Vacuum leak or low coolant. If the coolant is low, you will need to fill and bleed the system properly.

low coolant would cause idle surging, but this doesn't sound like the case. As far as the carb cleaner just use the straw it comes with, been using that to check for leaks for years, but don't soak the thing with it. another idea is to get a small vac tester and see if you have any shotty vac lines. Also if the idle remains consistently high after warm up and its at idle, try looking on the throttle body, there is a screw there that you can use to adjust for the idle. if this is a carb'd engine it could be a bunch of things wrong

[stephensimmons]

Now that a new one one me rite there!!

[88cool]

Update:

I pulled off a vac hose while the engine was cold. The same type of erratic idle happened. This makes me think that if it were a vac problem it would be an all the time thing, not just when the engine is hot (?)

The previous owner kept excellent records. The Fast Idle Valve, Electronic Air Control Valve (IACV in previous posts) and the ECU were replaced in 2008 ($1100). Also, the car has had quite a few coolant hoses replaced, including the small one that goes from the EACV (IACV) to the rear of the block.

....sounds like a recurring problem(?)

When the switch trips for the electric fan, the bad idle stops immediately. Way to soon for the drop in coolant temp to affect any sensors. Same thing with the A/C system.

I topped off the coolant (it was only a little low). I'm unsure of how to bleed off any air in the system though.

The more I get into it, the more I suspect an electronic faliure.

[88cool]

Oh yeah I almost forgot.... Chilton SUCKS!!!

[[email protected]]

I have been having the same problem with my 87 accord lxi. Sometimes my idle will even go to like 1700 rpms now. I have tried two different mechanics that cannot figure it out. I did see that there is a sensor on my thermostat housing that is broken, not connected, people say on other sites that there is a thermowax sensor there for the fuel inj as well as one for the temp guage. My temp guage works so its connected, but the disconnected one seems to be a tmp sensor for the fuel inj. I need to see pics of the area to see what I am missing, can anyone send me pics of their housing especially the sensors. The previous owner of my car also tried a lot to fix it.
Dan

[88cool]

I have been having the same problem with my 87 accord lxi. Sometimes my idle will even go to like 1700 rpms now. I have tried two different mechanics that cannot figure it out. I did see that there is a sensor on my thermostat housing that is broken, not connected, people say on other sites that there is a thermowax sensor there for the fuel inj as well as one for the temp guage. My temp guage works so its connected, but the disconnected one seems to be a tmp sensor for the fuel inj. I need to see pics of the area to see what I am missing, can anyone send me pics of their housing especially the sensors. The previous owner of my car also tried a lot to fix it.
Dan

According to Haynes and a few other sites your car (an '87) should have 4 different valves to adjust the idle. Each valve works for it's own system. One for A/C, one for A/T, etc.. I don't know if it's better to have the multiple valves or just the two.

[88cool]

Sheez. About the only real way is dogged persistence and a lot of luck. They can be buggers to find. I had the mother of all vacuum leaks and couldn't find the blasted thing till it started hissing at me one day. Turned out my intake manifold gasket looked like this:



Use carb cleaner or MAF cleaner is also supposed to work. I'd avoid soaking rags with it. Just spray it on the likeliest leak spots and stand back a little bit. And avoid obvious ignition sources. The cat isn't going to have any vacuum leaks, so don't spray on that. Ditto the exhaust manifold or the alternator.

Good Grief... Your lucky to have all of the little pieces of gasket still there. I had a Grand Prix GT that sucked a little piece into the cylinder. The way it ran after that, I thought the engine was toast.

[-$MOKIN-]

So what the hell s it? I still can't figure it out I replaced the egr valve

[88cool]

So what the hell s it? I still can't figure it out I replaced the egr valve

I haven't checked my EGR. Usually you will get a "service engine soon" light and the ECU will throw a code if the EGR is bad, so I haven't given it much thought.

[Harrison_Bergeron]

If it is temp related (it goes away when fan turns on) then my money is on the TW sensor, or low coolant. The low coolant affects the TW sensors measurements.

This is based on my readings here on 3geez.

[88cool]

If it is temp related (it goes away when fan turns on) then my money is on the TW sensor, or low coolant. The low coolant affects the TW sensors measurements.

This is based on my readings here on 3geez.

I'll check the TW sensor!

I arrived back in NN this evening. The Accord was cold and it had the problem. After it warmed up there was no problem!!! I'm getting really confused.

[a20soda]

ive been working on this prob for 3 days... my thread is in this section as well. i narrowed it down to a bad float in the carb. take off the breather and see how much gas is flowing in the carb during idle. if its dripping its too much. it should be such a fine mist that you can barely tell gas is flowing.

[Oldblueaccord]

Make sure the throttle cable has slack,loose, at idle esp warm. Also you throttle shaft could be worn causing erratic idle. Cleaning the TB blades with a rag and solvent cant hurt either.


wp

[88cool]

If it is temp related (it goes away when fan turns on) then my money is on the TW sensor, or low coolant. The low coolant affects the TW sensors measurements.

This is based on my readings here on 3geez.

Unless there is a huge bubble in the system, the coolant level is fine. I still am going to check the TW sensor though...

[Dr_Snooz]

Unless there is a huge bubble in the system, the coolant level is fine. I still am going to check the TW sensor though...

It only takes a little one to make the EACV act up.

[88cool]

It only takes a little one to make the EACV act up.

Haynes and Chilton both are silent about bleeding the system properly. What is your best method? From what I can tell the EACV is the highest point in the system.

[88cool]

I was finally able to contact the original owner. He siad it was the EACV acting up when he owned the car. I'm going to get one from pic-n-pull if I can (there is not much interchangeability). Unless somebody has a parts car in thier backyard (hint, hint)
The part fits:

HONDA ACCORD LXI (1988 - 1989)
HONDA PRELUDE 2.0 SI (1988 - 1991)
HONDA PRELUDE 2.0 SI 4WS (1988 - 1989)

As soon as I try a different valve I'll let everyone know how it turns out...

Thanks to all Geez