JDM '87 - run rough with black smoke after rebuild head

[Teratani]

Hi everyone. Somebody remember me about "car works on 3 cylinder" thread. Then problem fix with a complete rebuild of head. Now it's good (car works on 4 cylinder finally) but I have some carb problem now that I haven'r before head rebuilding:

-At cold car smoke black (reach mixture issue), and idle not going up anymore (fast idle doesn't works) but stay at 1000rpm very roughly

-When car is very well warmed up, smoke go off but idle and run still rough.

-Whose rebuild me the head told me throttle float on carb was open all the time both cold or hot car (so air float throttle open means choke closed....right?), and this is the reason why car start difficulty at cold. Yes, I knew about this issue so mechanic is correct.
Here is the matter: he fix air throttle to stay closed (choke opened I guess) when car is cold...and now these are problems.

-He rolling back at the previous situation but car still run roughly


I scare about mechanic touch something on carb that he doesn't know at all because these carb are a very pain in the ass when u going to try some setting...


How can I fix this? There's a write up that I can follow to fix it?

[2oodoor]

hey welcome back, good to see you kept the car !
no fast idle is a good thing with these pain in the ass carbs.
If it were mine I would either turn the electric choke all the way lean, or get some steel wire and tie the choke blade back some how on the outside of the carb.
I completley removed the whole choke hardware and tied the rod back that moves the choke blade and still had no problems with cold starts. It eliminated all crazy idles too.
This is an unorthidox way to handle the problem but it costs nothing with no sacrifice to the way the car runs or operates.
To start the car in cold weather I just pumped the gas pedal a few times and crank it. There was no fast idle so I had to stay with the car about a minute then go inside the house till it warmed up to defrost.
HOpefully the mechanic used NGK plugs too.

[Teratani]

If it were mine I would either turn the electric choke all the way lean, or get some steel wire and tie the choke blade back some how on the outside of the carb.
I completley removed the whole choke hardware and tied the rod back that moves the choke blade and still had no problems with cold starts. It eliminated all crazy idles too.
This is an unorthidox way to handle the problem but it costs nothing with no sacrifice to the way the car runs or operates.
To start the car in cold weather I just pumped the gas pedal a few times and crank it. There was no fast idle so I had to stay with the car about a minute then go inside the house till it warmed up to defrost.
HOpefully the mechanic used NGK plugs too.
NGK plugs yes.

In the past, choke blade was always tied to opened (choke closed) and yes I gave some some foots on pedal for starting but I haved crazy idle anyway: up to 3000rpm before calm down when car was comlpetely warm (thermostat opened).

I was reading some sticky thread write up mixture/idle and also shop manual...so there are 4 screw to turn for setting idle and mixture

[Teratani]

Finally we made it!!

Car now is good: run smooth and no more smoke after downhill due to head rebuild.

Next project is get out that catalyzer crap.


Thank u evreyone. I hope this time car won't make trouble anymore :D

[Teratani]

Maybe some useful information to whose own a JDM A18A and going to rebuild head. Head gasket to fit is that from Prelude 86-87 ONLY (not 83-85, has a different layout that won't fit). Other pieces from head gasket kit is good from standard A20A parts.

Thank you very much to user A18A for gave me information how to find head gasket replacement.