Good morning message board.
I initially joined up to bounce questions off a few of the members on this forum, although I think a thread is worth-while and necessary.
I have been having a very difficult time getting my 1987 Suzuki (Samurai) to pass smog.
I do understand, these little feedback carbs are installed on a few swifts and sprints (i do see minor differences in the carbs when they are side-by-side), although I think the overall concept is 100% the same.
I do see some very knowledgeable posts about the little hitachi/feedback carbs and the posts are very useful (mkc1962's posts about dwell for example), although I would like some specific feedback on my configuration.
First off, the smog numbers --
As you can see, I am failing the slow speed emissions test.
The smog guru didn't know what he was looking at and also failed me on my secondaries and my a/c idle up diaphragm saying "They are not on the underhood sticker, therefor it will not pass even if the emissions passed".
He didn't know what he was looking at!
A little background on my configuration --
Engine has a little over 8,000 miles on rebuild
Bored over 0.10
272 long duration camshaft
Doug Thorley header (has egr delete/ca smoggable e-o number)
Stock 2bbl feedback carb
Compression is 182 across the board
I have went through the Suzuki FSM about rebuilding the carb a few times now, and it seems each time I pass through the read, I find a little something else "amiss"...
Here is a list of my current fixes --
~~ Issues corrected on current repairs ~~
Choke linkage/arm bent -- fixed by replacing choke assy
Secondary Actuator/Diaphragm wont hold vacuum -- testing single nipple chevy sprint secondary actuator
No choke delay valve -- will need to locate one
Adjust choke arm higher to open butterfly 100% -- even though butterfly now opens 100%, the lower pin and linkage line do not line up
Swapped out my secondary diaphragm to the chevy sprint one for testing (Need to purchase oem one eventually)
Adjusted Float "lower" into bowl -- may need to be lower? ~11.5mm setting
Replaced needle and seat from "Japanese Kit" / adjusted float
Added seat filter
Soaked MCSV in cleaner and tested good after soak -- replaced lower o-ring
Moved gas line away from head, closer to carb
Found choke piston had pin-hole leak, replaced with sprint choke piston
Found and added a "choke delay valve"
Installed oem 2 nipple secondary diaphragm
Installed new o2 sensor
Found ECM harness at carb "twisted" badly (solenoids no comm to ecm)
Spark plug change
Found accelerator pump "jet" plugged, probed and cleaned
Adjusted valve lash
The thing that bewilders me is, when I follow mkc1962's forum post about dwell/duty, his readings are for a 3cyl and may not apply 100% to the 4cyl, but I would think the general concept is the same and the issue is, I can not get my duty ABOVE 11-12ish! And based on his forums posts, that is a RICH condition (in which I am experiencing)!
I am almost at a loss here trying to figure this out, and my concerns are
Cam shaft causing "idle-surge" -- When I am BARELY off idle (lightly holding the throttle up around 1200rpm) I can see gas "dribbling" from the upper primary venturi! I do not know why this is!
Doug Thorley header -- The o2 bung is a good distance away from the engine, and I read here somewhere that there may be an opinion that the o2 is "too far away" allowing it to cool under certain conditions...Also i should mention the doug thorley header o2 placement only allows readings of 2 of the 4 cyls.
I would really appreciate any feedback as I can not find anyone local that has any experience with these liltte carbs, and when I try to talk to different shops about it, they always put me off like I don't know what I am talking about and "don't want to mess with it"...
You would think the local shops would like to make $ right???
I am also VERY curious to know once and for all, does the mixture screw affect slow speed emissions? I can not find this answer anywhere and ALL the smog shops tell me the mixture screw is only for idle. I find this hard to believe since the idle and slow fuel circuit is one in the same --
I have ensured that all my attached solenoids are functioning and signals to the ECM are functioning.
I may re-check my ECM signals again for peace of mind.
I was also brainstorming a way to "wire up" a "closed loop" indicator so I can see that my ECM/Emission stuff is running on closed loop.
Here are pics of my rebuild --
Sorry for the long post, and please ASK me any questions and I will be happy to answer ANYTHING!
I need some secondary input on this as I am at a loss!
I feel I am going crazy doing the same thing over and over and expecting different results!!!
Thank you teamswift!
Edit -- More notes --
I do note a large amount of blowby from the oil fill on the valve cover. I thouhgt this was from rings not seating properly, although I see >180 compression on all cyls?
**valves adjusted after this video**
Jet configs for anyone looking for this data out there on the web--
Primary slow air bleeder 1 = 70
Secondary slow air bleeder = 180 -- (spare donor carb has a 140 here)
Float chamber -
Primary slow air bleeder 2 = 100
Primary slow jet = 53
Primary main air bleeder = 60
Secondary slow jet = 100
Secondary main air bleeder = 70
Primary main jet = 85
Secondary main jet = 140
Upper jet = 140
Lower jet = 65
MCSV Stamp = GV113-21A