93 festiva 5spd rpm drop, ticking sound, does my fan or water pump not work?

[510festiva]

Hi festiva friends! Finally joined the forum after lurking because i need maintenance advice.

I got this 93 5-speed back around January and it's been super for commuting. Recently I noticed the rpms drop very low before returning to normal after depressing accelerator during parking. I don't know how low because I don't have a tach but it's low enough that I can hear and feel something is wrong. It sounds like the engine is going to die then it returns to normal idle.

I've searched here and found that it is a possible vacuum leak or a problem with the IAC* I looked today for a vacuum leak by having the car run and squirting water on the vacuum hoses. I hoped to hear the idle drop when the water found it's way to the problem but nothing happened. I'm barely a baby grease monkey so perhaps I missed a hose or two? Anyone know exactly how many there are or a diagram that shows them? The one under the hood is pretty minimal.

If it's the IAC*, is it just a matter of disconnecting the hoses attached to it and cleaning it? I read it can be pretty involved because of springs involved? Is it pressurized? Should I prepare for a big mess if I unplug stuff?

Finally, while idling the car my radiator fan did not turn on once. I've never checked if the darn thing even works. Has it been your experience that the fan on these cars just doesn't turn on that often?

Here is a video of the car idling. It may be loud so watch your volume level. I hope you can hear the tick when I get near the IAC*.

https://streamable.com/iu2gs6

Any help would be super appreciated!

P.s. sorry for the very low exhaust note. My muffler tip rusted off and the inside of the muffler is just a box now, all the walls have deteriorated to nothing.

Happy driving!

[WmWatt]

Sorry I can't view the video as I don't have high speed Internet, just dialup. However the ICM (Ignition Control Module) is an electronic device which has no hoses attached, just wires. It performs the job which used to be done by the points, opening and closing to time the spark at the spark plugs. When it goes bad, usually because of heat, the engine usually stops and won't start until it cools down. I don't think they can be repaired, just replaced. It doesn't sound like an ICM problem you're having.

Electically the radiator fan is always on but when the engine is within normal operating temperature it is kept off by the temperature sensor. If you disconnect the sensor the rad will always be on. I can't remember where it is but a search of this site on radiator will retrieve the information.

[510festiva]

Thanks WmWatt! I'll find that sensor and try to check the fan operates.

Sorry i meant to say IAC. I'll fix it. It looks like this:

[WmWatt]

My car is carburetted so doesn't have one but the Haynes manual suggests unpluging the electical connector and checking the resistance with an ohm meter which should read 7.7-9.3 ohms. It also suggests checking for vacuum leaks. In addition to misting you can squeeze and pull on hoses looking for cracks and loose fitting. Haynes calls it Idle Speed Control-Bypass Air (ISC-BPA) Haynes calls it IAC valve in the trouble codes section. Is the Check Engine Light coming on? If so it will have stored code 29 (1994 and later) or 34 (1990-1993). Suggests checkign the wires between IAC and ECM and IAC and fuel injection main relay. If you're lucky it will be a loose hose or dirty or corroded electrical connection.

Haynes says it does two things. When engine cold increases idle speed (sounds like a choke). Also functions as controller for idle speed during normal operating. Controls amount of air into intake by funelling air from ahead of trottle body into intake.

PS I did a search of this site on IAC and there are lots of old posts which mention it. See "search" box at top left of screen. If you want to read back through some of that you might find the answer to your problem.