Hard start/run when wet/cold

My '87 Si hatchback (220K miles) has an acute cold/wet weather
problem. During cold wet rainy days, car will stutter and backfire
until engine reaches full operating temperature. Car starts instantly
when cold, but will stutter/backfire when given 1/8-1/4 throttle at
low rpms. When revs come up, will take more throttle w/o
stutt/backfire. If car is parked before reaching full temp, say, to go
into the market for 10 mins, car will hardly restart. Needs multiple
10-20 sec start attempts (no gas) until get a cough, then again, then
will catch and be very stuttery and stall w/ too much throttle, but
runs. If gas applied, before start, huge embarrasing backfire, so I
know the injectors are getting fuel. Restart problem occurs when cold
and dry, but not cold engine stutter problem. Problem does not exist
during warm weather.

To me, it sounds like either a electrical (condensation?) or choke
problem, but I know nothing about either on a Honda. I do most of my
own mechanical work, but am more familiar with old American iron.
Never been into the "ignitor".

nb

 

How old are and who manufactured the distributor cap on your
Honda? If they are either old or non-OEM, I would start by
replacing the distributor cap and rotor with new, genuine
Honda ones. Rainy day starting problems often trace to the
cap, from my reading and one experience with another
Japanese make. They're cheap parts to replace--under $50.

Then I'd check the wires' resistance and inspect the wires
while running with the hood up in the dark. Look for
sparking. If any wire's resistance is over 15k ohms, then
replace the wires. Or if the wires are non-OEM, replace
them.

What's the status of other maintenance on the car? E.g. how
old are the plugs, and are they OEM? Fuel filter, air
filter? PCV valve? Coolant thermostat fairly new and OEM?
Coolant been changed and system purged of air?

I don't suspect any of the above, but any could interfere
with your troubleshootin.

For now, I agree.

I doubt it's the igniter. It tends to fail "all or nothing"
and I have not heard of its operation being subject to
weather variations.

 

replace distributor cap and rotor with new OEM.

 

replace plugs, leads, cap, rotor, etc. use oem - only a couple of bucks
more expensive, but 10 times better quality. use the honda spec ngk plugs.