Hey guys I have a '97 Civic Ex with about 170k on it. When I first bought the car about 7 months ago it had a generic tranny code as well as P0505 (IACV). I ignored it because I didn't have any symptoms. Up until last week everything was fine. Then, on Tuesday morning, the car started up fine but the RPM fluctuated wildly between 1300-1600 until I gave it a little bit of gas and then it settled down and ran perfectly fine. It did that a few times on startup since then with no noticeable problems while driving, but now, it won't even start at all. It will turn over forever but doesn't even try to start.

I cleaned the IACV and reinstalled it, no luck. I checked for spark last night and its getting a bright orange spark. I tested using the spark plug though so not sure what to make of the orange spark.

I also tried starting with starter fluid, and it had no effect. I might no have used enough though.

Is an IACV failure capable of causing the engine to not start at all? I unplugged the computer when I was cleaning the IACV and when I plugged it back in the CEL was gone so I don't think there are any codes to read.

EDIT: I can hear the fuel pump hum for a few seconds when I turn the ignition to the ON position.

Thank you

 

tach weirdness can be bad icm, just had similar issue.
airtex icm is more heat tolerant than sketchy factory nec unit.

Advanced Ignition Troubleshooting - Team Integra Forums - Team Integra

other no start stuff:

Starting Problems

 

Wow those links are great, thank you! Luckily I'm on spring break right now so I have some time to work on it.

 

more greatest hits:

Honda Acura Essential Electrical Repair Website. Troubleshooting Main Relay, Coil, Igniter, etc.

Advanced Ignition Troubleshooting - Team Integra Forums - Team Integra

DIY Ignition switch cleaning - Team Integra Forums - Team Integra

 

Thank you for the super helpful links.

I spent a good amount of time tonight cranking it in clear flood mode and it eventually started. It had the same problem as before where the RPM's were wild on startup until I gave it a little bit of gas and then the RPM's immediately settled and it ran perfectly fine.

What could cause an issue like this where the car is ONLY affected while the key is turned and the car is starting up, but shows no other symptoms at any other time? I know some of this stuff isn't really very intuitive but it seems like if there was a persistent spark or fuel delivery issue it would show up at other times, not just at startup? But maybe since components are under a lot of stress at startup, failing parts begin to show their wear?

 

when's the last time plugs/wires/cap/rotor were replaced if known?
i'd still suspect icm first unless you've tested and/or replaced it.
having a look at the ignition switch internals would be next.
just replaced mine, it was overdue after 22 years lol.

 

I replaced the plugs when I first bought the car, but to the best of my knowledge the rest hasn't been touched. I will test the ICM and see what I get

 

if the switch looks black like at the link i wouldnt bother messing with it.
i cleaned mine and noticed a difference but for $50 or so just replace as it's
a known issue and can be dangerous (see gm scandal).