TeamSwift

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
10:1 pistons
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)
Oil change
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**

[youtube]https://www.youtube.com/watch?v=ZCnePGcAACE[/youtube]

Jet configs for anyone looking for this data out there on the web--

Air horn-
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

MCSV -
Upper jet = 140
Lower jet = 65
MCSV Stamp = GV113-21A

You seem very close to solving the problem.
Just a few minor tweaks and you're done.

This thread regards the MR08 as standard equipment on a G10, but I've found the emissions requirements are essentially the same as the 4 cylinder:

viewtopic.php?f=31&t=53435&p=399999

It mentions part numbers which work for the G10 and may also apply to your application.

You have low NOx, so I will go out on a limb and say you have a fairly new cat.
But still you have high HC and CO, so the combustion, like you mention is too rich.
To get ideas, I usually look at this page, because I simply can't remember all the variables involved in each condition:
http://www.ratwell.com/mirror/interro/techgas.html
and you have a combination.

The valves might be set incorrectly.
That would be a cheap fix.
You may have excessive valve overlap at low speed which cannot be corrected with a carburetor in stock trim.
Hopefully, I'm wrong on that suggestion.

Low speed problem, so I'd look at the primary circuit in the carburetor.
Those O-rings look a bit thick on the primary discharge nozzle.
About twice as thick as stock ones?
Again, I could be WAY off on that.

This link describes the primary circuit in general:

http://s145.photobucket.com/user/pacapo ... ort=6&o=45

I need a little help with the logic, but if I go with a larger number on the primary air bleeders will it lean out?
You have to read the description in the link above and help me remember.
Is the bigger number the way to go?

You have a blowby issue still?
A reversed check valve or non-functioning PCV might be to blame, but I know you're not prone to those 'newbie' errors.
There should be a slight negative pressure at the oil filler valve, no?
It seems too simple, but never overlook the obvious.
Is the hole open for the PCV valve?
Did someone 'fix' it?
Ha!
A wise guy sometime in the past tried to screw up the car for you?

Surging upon acceleration?
Everyone always jumps on the vacuum line routing, but again, I know you'd have that all sorted out by now.
So what could be causing that, and if you've fixed it, what did it take to repair the surge?

This post is just throwing out some ideas to get those numbers down where they should be.

Not seeing where you've got the oxygen sensor, or how you've hooked up your AF gauge also might raise a few eyebrows.
Again, not being critical, but just making sure you dotted your 'i's' and crossed your 't's'.

Figure that the car in stock trim would pass smog.
Then look at the systems you added or modified.
Even with 180 compression across the board, she should pass easily.

You cannot adjust the idle mixture to match what the carb manual requests?
http://s145.photobucket.com/user/pacapo ... t=6&page=1
It might indicate a problem before (above) the idle mixture screw.
mkc1962 had a problem similar to yours when he switched to a different number MCS, if I recall.
But lately he's improving his vacation property and working on his Turbo Sprint.
And he's sold his carb version Sprint so he might not be as much help as his old posts.

If a different number MCS doesn't bring the numbers down, then going back to the bleeder valves mentioned by glacierburst might help...or vice versa.

You are almost there, like I mentioned at the beginning.
Just take it one step at a time and you'll spank that smog tech next time you drive it in!!!

BTW
I am ashamed to say that I need help before I take a car in for smog.
If there's any question - say I changed some major things on the power train, I have to pull out an ancient CO tester

hook it to the battery, and let it sniff the exhaust.
That way, at least I'm sure of ONE exhaust component.
Some guys claim they can smell the exhaust and tune a carburetor.
Absolutely no way I understand, but hey - to each his own.

In your case, look at the air bleeder valves in the primary circuit and see how they compare with a stock carburetor set up.
That's a pretty cheap first step.

You've put a helluva lot more time into that car than I have on this post, so don't be too hard on me if I miss a few details.

Keep an open mind, a positive attitude and extend this thread as you wrap up the final tidbits on your build.
It's probably a blast to drive as is!

Rather than edit the above post, I'd like to add an additional one.

Here's a smart guy who posted vacuum results on his vehicle:

https://www.youtube.com/watch?v=u1uHr8FvTdU

but you can tell more about an engine at idle:

https://www.youtube.com/watch?v=cCMBMWDibow


This web page seems to describe normal readings:

http://www.gregsengine.com/using-a-vacuum-gauge.html

Again, it might just be me...but something is amiss in the overhead!

Thanks much for the reply!

Do you have an alias of Phil N Ed?


That cam adds for some fun!


Thanks for your replies and I will be reviewing your supplied links, thanks!

More supplemental info as I think about it

Tires (alot of tread on the road) 275/60/15

AFR gauge is wired into the o2 lead behind the coupler (so not to have to mess with it each o2 replacement)
Ever since I replaced the o2 sensor (cheap $5 ebay sensor), I notice my afr gauge reads VERY lean?
How is this possible if I am running rich? Could the o2 sensor be a cheap dead sensor, fooling the ecm into a rich condition?
I guess I could test the o2 tomorrow with a torch or better yet just pop a denso/bosch on there and see how it reacts? (The youtube video of the afr gauge was with my old o2 in there)

Plug pics --

Cyl 1





Cyl 2





Cyl 3 ** I DROPPED THE PLUG AND IT HIT THE SIDE ELECTRODE, THAT IS WHY GAP IS DIMINISHED **





Cyl 4





I am under the impression that since the PCV is over cylinder 3, this is the reasoning for the "different coloring" on that plug.

Where can fuel be coming from to be pulled through the upper primary venturi at a light idle?

Looking at the carb cross sections it appears I could theoretically reduce the primary main and the lower MCS jets to throttle fuel flow?



I am looking at the primary mains (not the slow circuit) since the fuel "dribbles" from the main discharge nozzle under light load...(Where is that fuel coming from! )

Also noted is my 5th switch is bad, but I don't think this comes into play until you are in 5th gear (high speeds)...

IIRC, the 5th switch reads "infinity" until it is engaged (stick in 5th), then reads "zero"...

I need to find a good replacement, the plastic tipped ones don't last it seems...

Sorry for the adhd type post, just dumping the thoughts out here while i think of them...

Pics --

Choke strangler arm bent badly


Fixed


Float


*Noted is the thorley header blocks the egr passage back into the exhaust*


Variances in mix screw (flat washer&gasket VS no washer or gasket)

[quote="87Suzuki"]More supplemental info as I think about it

Tires (alot of tread on the road) 275/60/15

AFR gauge is wired into the o2 lead behind the coupler (so not to have to mess with it each o2 replacement)
Ever since I replaced the o2 sensor (cheap $5 ebay sensor), I notice my afr gauge reads VERY lean?
How is this possible if I am running rich? Could the o2 sensor be a cheap dead sensor, fooling the ecm into a rich condition?
I guess I could test the o2 tomorrow with http://www.comparateur-mutuelle-assurance-sante.com a torch or better yet just pop a denso/bosch on there and see how it reacts? (The youtube video of the afr gauge was with my old o2 in there)

hello! i'm wondering who is the best suzuki or kawasaki or the american ford?
thanks!!

Hello,

I have never owned a Ford or Kawasaki vehicle, so I would be biased in saying Suzuki.

If Doctor Phil is on the job...your ill's are soon to be cured!!


JVS....you crack me up!!

glad to see still coming here on occasion can brighten my day!

_________________
Mike
Valley Grande, AL
1986 Sprint plus

Do you maintain a personal fleet like I do?
Why do we do it?
Because it's what we enjoy and because we CAN.
2011 camaro, 2005 Vibe, 2016 Outback, 06 Expedition, 87 Porsche 911, 87 Turbo sprint, 82 Brat, 73 gmc 4x4, 69 camaro, 99 Gl1500 Honda Goldwing, 12 Kawasaki klr650, 2012 Kubota L3200, and we wont even go into the small stuff.

Just a small update as I further my progress...

Using my afr gauge as a tool and thinking about it (afr reflects lean condition although running rich via sniffer test), i pulled the o2 and bench tested it...

Apparently the "new" o2 sensor I installed out of "good practice" was intermittently working. (my old o2 was prob fine, turns out to be bad practice just throwing parts in "just because")

I held the o2 in a vice and clipped my dmm negative side to the o2 body, and the positive side of the dmm to the o2 output lead.

I used a torch to heat up the flared end of the o2 sensor and I would not see any deflection on my dmm...

I jiggled the output lead and saw deflection on the dmm...

I dropped in a denso o2 from the local parts store and now I can see my afr gauge deflect as I would expect.

I drove it yesterday to see how it reacted and it appeared I am still running rich...

When I let off the gas I can see that the fuel cut and MCV appear to be working (full rich to full lean when I let off the gas)...

Doing more brainstorming about what controls different positions off idle, i looked at my idle micro switch very closely and tested it at the carb wire harness.

It appears the idle micro switch is also intermittent, although when I bench tested the carb on rebuild, my notes say the switch tested good?

I have a few spare micro switches I can use, although I may source some new ones...

Also noted, I finally was able to get a stable/readable "duty" number out of my duty coupler.

It appeared I had my mixture screw pretty far in (lean) being my initial readings were 0.00...

At first glance, I thought something was amiss, although when I turned the mixture screw out, I began to see readings.

Being the FSM states a duty of between 10-50, I attempted to get the value somewhere around 30.

I feel I am very close, and after I swap out that idle micro switch, I plan on another smog dyno...(I will post those results when I get them)

Thanks for the links again pacapo, some of the info sparked ideas in my mind.

Much appreciated!

Well, got it to pass!



The smog ref still squabbled about the secondary diaphragm and had to call in his helper.

They talked it over a good few mins and came to the conclusion, if it came stock with a secondary system, it is fine.

They had a copy of the FSM (digital) and then flipped to the carb rebuild section.

They both went ah ha! and said there is the diaphragm and said "nothing looks off to me".

I also believe the emission numbers could have been lower if the car was fully warmed up.

It sat in their shop for a good 20 mins not running.

Then they fired it up and put it right on the dyno...

I know that choke was a little bit closed.

Thanks for the input and hope this helps someone down the road!

Good job

So basically you clean and replace some part and then adjust... eh?

Compare to first and second results. first one is pretty not burning properly. second one is pretty cold to run but still acceptable for emission.... just need to adjust the mixture otherwise you are going little faster.

_________________
sorry bout my bad english

Here is (in chronological order) the repairs I believe made this "work" (the other listed repairs are also a good guide, but below is the "meat") --

Choke assembly "tweaked" and not opening the butterfly to even 75%
This was a no-brainer, although having a spare carb proved beneficial since the "choke assembly" linkage comes off as an entire unit.
I still don't understand why they would make the choke this way (wax/water deal) and it should have been designed to "fail open", not fail choked!
I don't know where you would source a choke assembly on its own, you would need a reman carb for this.

Various diaphragms with pin-hole leaks
I found, during the rebuild, my choke pull off and secondary diaphragms were "leaking".
Again, having a spare carb helped in this situation, although I had to find the secondaries on ebay. (My spares were leaking too!)

MCSV (mixture solenoid) "sticking"
This may have worked itself free under some good use, but when I had the carb apart, I thought it was a good time to test it.
Applying +12vdc to the solenoid OUTSIDE of the carb proved useful as I could see the solenoid working and not working..
A little bit of carb cleaner fixed this right up.
(New o-ring here also)

Wire harness side of carb connections "twisted" making no comms to ECM
Untwisted harness and checked "feedback" to ECM.
The FSM was weird at first on how to test this, but you pin-out the wire harness side of the "molex" type plug (the backside).
(You test the solenoids/switches from the back of it, where the wires come in).

"New" O2 Sensor off eBay (bosch $5 knock off) was bad
This one really threw me off since I continued to "assume" the one I put in was "good".
After realizing the afr gauge wasn't quite right, I pulled it and sho-nuff, it was toast NEW!
New denso from napa solved this.

Idle micro switch bad
This one was also tricky and I believe I still need to tweak it.
I could press the micro switch in with my finger and it tested good, but the carb linkage would not press it in all the way.
I have 4-5 "good spares", but might pick up a few new ones since they see a lot of work (the switch on/off/on/off).
I have sourced new switches from Omron, I may buy a few to keep around.

I think I have answered my question about the mixture screw.

On idle the throttle plate butterfly's tolerances are VERY tight and can ONLY draw fuel from the idle discharge port (mixture screw)
Off idle < prob around 25%, the butterfly is not open enough to draw fuel from the upper primary venturi and not closed enough to draw from the idle discharge port and draws fuel from the off idle discharge port.
I believe (I hope someone can confirm this) that when the throttle butterfly is more open/off idle 25%ish, the vacuum/pressure is greater than at idle and that causes the fuel to be drawn from the "off idle discharge port". This would make sense for the need of the "off idle micro switch". Now you are "off idle" and need the MCSV to do the "fuel mixing" for you and not a "mixture screw".
Off idle 100%, you are drawing fuel from the primary venturi. The vacuum/pressure is raised high enough to draw fuel from the upper most discharge port.

I think that's how it works!

Pheeeew!

[youtube]https://www.youtube.com/watch?v=Kr3x2VH1dJk[/youtube]