Hard start/run when wet/cold

[notbob]

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

 

[Elle (2)]

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.

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?)

For now, I agree.

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".

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.

 

[SoCalMike]

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".

replace distributor cap and rotor with new OEM.

 

[jim beam]

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

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.