YACT: My RPMs are too low to do an emissions inspection so I can register a 1990 Honda Civic

[Squisher]

Take it to another shop that'll adjust the screw to pass the test. The machine'll have a tach on it. Then have them put it back when they're through.

Don't take your car back to the first shop.

 

[Thegonagle]

Well, I'll be. . .

OK. I wish I had a scanner.

It looks like I was about half right, half wrong.

There is an "Electronic Air Control Valve" (EACV) which is supposed to be disconnected while performing the adjustment. The adjustment procedure does set the very screw that I was seeing in my head during my previous posts: the one that the main throttle closes against. Because the EACV is disconnected while performing the adjustment, it is taken out of the air circuit, and the base, MINIMUM, idle speed is adjusted as follows:
[*]All Civics and CRX with 1.5L engine--575-675 rpm
[*]CRX HF--450-550 rpm
[*]Civic/CRX Si, and 4WD wagon--500-600 rpm
Then, once the EACV is reconnected, the idle should be between 700 and 800 rpm, i.e., computer controlled.

I think it's possible that the EACV is not functioning properly, resulting in the too-low idle.

Does the idle speed change at all when the EACV is disconnected? If not, just adjust the screw so it will idle at about 800 rpm, and either be happy (ghetto fix), or get a replacement part at a junk yard so it will start and run as the engineers intended (proper fix).

BTW, a hand-held tach with volt-meter function (a mechanic's DMM, if you will) should cost around $30-40, maybe slightly less, at an auto parts store or Sears.

 

[OrganizedChaos]

sounds like crap to me

 

[Eli]

Originally posted by: ThisIsMatt

Originally posted by: Thegonagle

Originally posted by: Eli
So.. According to you, it isn't adjustable, but it's adjustable.

Thanks for your incredible insight.

It may be "adjustable" by holding the throttle plate open, but that's not how it's supposed to be done. At idle, the throttle plate is supposed to close completely, while the computer operates a seperate "throttle" that bypasses the main throttle. This little bypass throttle is known as an Idle Air Controller (or Idle Air Motor), and it's not adjustable, unless you reprogram the engine's computer.

So, my "incredible insight" is actually a ghetto "fix" that could cause problems of its own.

:|

Don't mess with eli, he's the resident engine expert :roll:

I guess I forgot the "".

 

[Shawn]

Originally posted by: Thegonagle

Originally posted by: Eli
So.. According to you, it isn't adjustable, but it's adjustable.

Thanks for your incredible insight.

It may be "adjustable" by holding the throttle plate open, but that's not how it's supposed to be done. At idle, the throttle plate is supposed to close completely, while the computer operates a seperate "throttle" that bypasses the main throttle. This little bypass throttle is known as an Idle Air Controller (or Idle Air Motor), and it's not adjustable, unless you reprogram the engine's computer.

So, my "incredible insight" is actually a ghetto "fix" that could cause problems of its own.

:|

That's how I adjust my idle. Not really any other way to adjust it without getting an aftermarket ECU. It has never caused any problems for me.