1997 civic stalls at idle once hot

My '97 civic dx hatchback started stalling while idling once it gets
hot. The car starts fine and runs ok, but once the engine gets hot,
around 15-20 mins driving time, it will stall once I come to a stop.
It will crank back up and run fine until the accelerator is depressed,
then instead of returning to an idle speed it should, it dips way below
that and stalls. I have not found any vacuum leaks and no codes are
generated by the ecu. Any ideas? It's a 5sp manual, it that matters,
with 296,000 miles.

Thanks,
Tom

 

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Wow . . That's one of the best-written descriptions I've ever seen.

Anyway, how full is the reservoir? Is the temp needle going higher than
previous? With a flashlight, have you checked how full the coolant
reservoir is at the end of the day, and in the morning?

I think you're low on coolant and / or your rad fan isn't cutting in
because of it.

Not related much, but have you replaced the PCV with a Honda one?

'Curly'

 

These are the classic symptoms of a failing distributor coil: As they begin
to fail, they get finicky after warmup. How old is the car's coil?

My 91 Civic coil did the exact same thing a few years ago: After 20 minutes
or so of warmup, the car would die at stops. Eventually it would have to be
allowed to completely cool down before it would start again. It got worse
and worse.

But try checking the coolant levels, like Curly said, first. I'm not
optimistic that it's a coolant-failing-to-get-to-engine-control-components
problem, but it costs nothing to do this.

Are your ignition wires, plugs, distributor cap, and rotor up to date?

Fuel filter and air filter?

 

I'm almost certain my coolant level maybe low. I will check that this
evening. I've never replaced the pcv valve. Think I actually bought
one once, but could not find it so who knows where it ended up.

Thanks,
Tom

 

The plug wires have been replaced within about 20,000 miles with Honda
ones due to some other ignition type problems I had at that time. The
plugs are NGK and have less than 20,000 miles on them and look ok. The
dist cap and rotor are both up to date, but from AutoZone or Advance.
Distributor coil, eh? Any way to check it, or just replace? What are
the odds that this is caused by IAC? Btw, if I turn the a/c on the car
never stalls albeit guess that's expected since the ecu increases idle
speed?

Thanks,
Tom

 

btw, the fuel and air filters are both new enough to not need
replacement yet

 

If it's the IAC, then from my reading the most likely culprit is inadequate
coolant to it.

There are some resistance tests one can do on the ignition coil, but even if
the coil passes them, word here is that doesn't mean it's working okay. The
tests should be given at the following online Honda manual, under I
believe electrical, ignition system:
http://www.honda.co.uk/owner/CivicManual/index.html

I would consider going with OEM on the cap and rotor. It's only a few more
bucks. I have gone non-OEM on parts like this in the past and found it to be
a mistake, generally speaking.

I'd be guessing with the A/C but wouldn't use that datum to rule out any of
the above.

The distributor and its parts are the Achilles' heel of 1990s or so Hondas.

Elle

 

Hi 'Curly'

The resevoir tank was empty and the radiator took a bit of fluid as
well. I think filling both made some difference (or was that due to the
outside temps dropping 30F?), but the car still cuts off at idle. I
have never replaced the pcv valve. What do you guys suggest next?

Thanks,
Tom

 

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Check the reservoir and top up to MAX if it's gone down overnight. As
the engine 'burps' out air, it will sip the reservoir dry each time you
cool the engine down. Use Honda premix, and no tap water.

'Curly'