Hello all I have a 94 Honda Accord LX Auto Transmission. I'm currently trying to figure out some idle issues but noticed that previous to getting the car someone had already messed with the idle adjustment screw. 😑. Ever since then I've been trying to follow the base idle reset procedure but can not seem to get that right. My understanding is that idle screw isn't supposed to be messed with and if there's an issue with the idle, messing with that screw isn't the answer. Does anyone know what it's set to from the factory so I can set it back and further rule out the other issues properly?

 

If you're talking about my post in the DIY section about setting the base idle, here's a few things...

Are you talking about the idle-air adjustment screw? That's #1 in this picture and you ARE supposed to be adjusting this one during that procedure. It's in a deep-ish hole above the bore of the throttle body, so you only see the screwdriver slot in that hole. Check whether it's O-ring is OK because that might be a vacuum leak causing your problem.

The screw that you're not supposed to mess with isn't shown separately, but it's the hard stop for the cable-drum on the far side of this picture. That one is only just supposed to prevent the throttle plate from wedging stuck closed.

Make sure you check for all the other things in that thread, like vacuum leaks, air in the cooling system, and FITV (#14).

You also have a lot of vacuum hoses all over the place, and if the previous owner messed those up you can try to put them back where they belong. I never had a 1994 so I think other people might be more help with that process...

 

That makes perfect sense to me! Yes I was referring to the screw referenced Number 1. Yes I am attempting to follow the procedure to reset the base idle. My current issue is when I go to unplug the IACV the idle doesn't drop. It pretty much stays the same. When i screw it all the way in it only drops to about 600 to 650 rpm.

 

That's kind of classic for a vacuum leak.

FITV might be loose? That's supposed to be completely closed when the engine is at operating temperature.

Like I added to my post, you have a lot of vacuum hoses to check. Dry, cracked, loose, or connected to the wrong place??

 

So my thinking was on the right track. I was thinking a vacuum leak. For the life of me I can't find it. I've checked fuel injector orings, all hoses that I can see, i sprayed carb cleaner all around the intake manifold and hose connections to try and find it. Still no luck. I did take the FITV off, clean it, and screw it all the way back in. Since adjusting and cleaning the FITV i bled the cooling system. Original issue was car would stall when coming down to an idle at the same time I'm easing to a stop. It only stalled when easing to a stop, strictly intermittent issue, very frustrating. It screamed a vacuum leak to me at this point, and with not being able to properly adjust the base idle I feel that's it even more but I'm at a loss of where to look at this point. I can give a list of parts that have been replaced with possible relation to the issue.

 

No profound ideas, but a couple obscure places for a vacuum leak...

What about a leaking diaphragm inside the cruise-control vacuum tank?

Being an automatic, it should have a vacuum-operated rear engine mount. That's the one about center, down low, between the engine & firewall. That system has more vacuum hoses, a solenoid valve, and the mount itself as places for a vacuum leak.

Don't forget to check for vacuum leak at the brake booster & the hose feeding it.

 

Thank you for the ideas. I will be checking the cruise control as well as the rear engine mount area. Didn't even think of that one. I did check the entire brake booster line as well as the area around the master cylinder and no issues. Hopefully I can find the issue. Hondas run like a dream with no vacuum leaks, the only problem is they're super prone to them! 😊

 

This is the kind of discussion that's better suited to the General Tech board, so I'll move it there. I originally didn't notice the duplicate over there...

If you still suspect that the stop-screw for the throttle shaft was messed with, you can try that. It has a jam-nut which you loosen then back it out a little at a time until the throttle plate closes completely without wedging stuck. (It wouldn't be the first time that someone tried to adjust the idle using that screw) Put some paint over the jam-nut & screw after you verify that it doesn't stick closed when it gets hot.

While it's most common for the IACV (#19 in the first picture) to stick because of being dirty, it's possible for it to go bad.