28/32 ADHA Way too Rich for Smog

[kbolden]

Hi folks - well for the second time I didn't pass CA smog. It is frustrating, as when I bought the car 2 years ago it passed with no problems. But a year ago my mechanic pointed out that the carb wasn't mounted correctly and 'fixed' it for me.

Now, I can't get the co% down. It was at 8.75, and I leaned out the mixture screw until it was tight. I put on a new Cat (had to do that as mine was out of date), changed oil/filter, changed Air filter, and put in new plugs. Now it is 8.5!

I could order a new idle jet, but not sure why I should have to do that. Or, perhaps the float is off.

Any ideas? I'm not very versed in carb maintenance, and am gun-shy of taking it back to the same mechanic (FYI - he dented my car while he held-on to it for 2.5 months).

Any ideas?

Thanks in advance...

Kevin

[kilrwail]

You might start by cleaning all the jets (idle and main) with compressed air. I don't know how you can measure progress without returning to the testing facility though. Make sure the points are gapped correctly and the timing is properly set..

[wetminkey]

Like kilrwail stated, be sure that your engine is setup and timed properly first.
Then,...carb problems are usually solved by buying a rebuild kit, disassembly and soaking in carb cleaner.
Rinse + compressed air to dry and clean all air passages. Reassembly with the new parts, set float level, set air/fuel mix screw, and adjust choke initial setting to closed when cold. Start/warm engine, adjust air/fuel mix screw (to fast, smooth idle).
It's actually pretty easy, once you have the rebuild kit's new parts,...
Tip: Close attention to disassembly, so that you can reassemble EXACTLY the same way! And the carb cleaner part is important. A lot of folks try to skip that step and their carbs run crappy,...
Otherwise general maintenance is a little spray of carb cleaner before adjusting the air/fuel mixture screw.
Best of luck with your Spider!
Todd Compton.

[kbolden]

Thanks guys. Kit is ordered and we'll just start working away at it!

One other question - it looks like the PO put a BB in the line to the Charcoal box, and left the return OPEN on the carb (so vacuum is just sucking fresh air). Best practice or really bad idea???

Kevin

[wetminkey]

I'm unsure of exactly what you mean, but vacuum should never be 'sucking fresh air' without filtration.
If you have a vacuum leak, it could help explain why your car will not meet emissions,...
The "charcoal box" (vapor canister) is a good thing,...it filters fuel vapors from the gas tank and sends them into the carburetor to be burned. Otherwise, the gas tank vents to the atmosphere (or has no vent and causes a vacuum as fuel is pumped out,...!). It would be best to reattach the hoses to the canister and carb after ensuring that they are clear of obstructions.
Best of luck with your Spider, Kevin!
Todd.

[geospider]

Kevin,

I hear you. I will be taking my Non-smog carb set up off and legal stuff back on: for 2 days anyway: get smogged and take off again.
Do you know a good carb guy? Not a general mechanic, but just carbs/fuel injection.
They could set it up quickly. can also go to Pierce Manifolds and go through their step by step; lean best idle: other info there as well.

https://www.piercemanifolds.com/category_s/313.htm
Where are you located?

Geo
Concord, Ca

[85redpini]

your throttle shafts my be worn out.

you need a rebuilt carb from a vendor that has them rebuilt by a major USA rebuilder, a carb kit is not going to do it.
only one vendor sells rebuilt original fiat carbs
http://www.spiderroadster.com/124carb.htm

Hi folks - well for the second time I didn't pass CA smog. It is frustrating, as when I bought the car 2 years ago it passed with no problems. But a year ago my mechanic pointed out that the carb wasn't mounted correctly and 'fixed' it for me.

Now, I can't get the co% down. It was at 8.75, and I leaned out the mixture screw until it was tight. I put on a new Cat (had to do that as mine was out of date), changed oil/filter, changed Air filter, and put in new plugs. Now it is 8.5!

I could order a new idle jet, but not sure why I should have to do that. Or, perhaps the float is off.

Any ideas? I'm not very versed in carb maintenance, and am gun-shy of taking it back to the same mechanic (FYI - he dented my car while he held-on to it for 2.5 months).

Any ideas?

Thanks in advance...

Kevin

[kbolden]

Thanks everyone for comments. I've posted some pictures here: https://www.dropbox.com/sh/xui44ecan6k6 ... ABxla?dl=0

A few questions marked on the photos:

1) What exactly is that port, and where should it be connected? (Photos 1 & 2)
2) On the Vapor Cannister, it seems to not be plugged in the top. (Photo 3). Also, PO put a BB line into the 3.5mm tube running to EVAP. I'm going to pull that out, but don't have any idea why someone would do that...
3) Any ideas if any of these three are culprits either of the CO% being too high, or if perhaps they are keeping me from leaning-out the fuel? I ask since I've got the fuel all the way lean and it is still purring...

Thanks!

Oh - and I'm in San Jose... No good Carb guys that I know-of here.

[wetminkey]

1.) "Crankcase blow-by connection".
Bottom of vapor canister.
2.) Large hole at the top of my vapor canister is either plugged or capped, not open. I'd plug that hole, since the canister should be vented by the rest of the system, once operational.
Not sure which line you refer to going to EVAP, but remove the BB,...sounds like you know where the line goes already. I thought you referred to the gas tank vent,...but I could be wrong.
3.) Any vacuum leaks will cause changes in the air/fuel ratio,...certainly could be a part of the problem!
I'm sorry I can't answer this question. Perhaps another forum member will post with the answer,...I'd like to hear, also.
I sure hope this helps you pass emissions! Best of luck!
Todd.

[kbolden]

I think I figured out what is going on...

1) The mechanic working the carb must have incorrectly connected the Vacuum advance port to the vapor canister
2) The Vapor port was left open
3) The Vacuum line to the electronic distribution was left disconnected (interestingly, the line doesn't seem to reach anywhere near the carb)


So here is my plan:

1) Pull the BB from the vapor line. Connect the Vapor Cannister to the open port.
2) CONSIDER connecting vacuum advance port to the distributor. The car is running well, so not sure if I should just cap this port for now. I just don't know if this will create an issue with timing on the engine.

If all works well, celebrate with a beer. I still don't get why there are zero ADHA pictures/labels. Everything says it is similar to an ADFA, but when troubleshooting, similar just doesn't cut it...

[wetminkey]

So your's IS an ADHA,...?
If so, it has a number of 'add-ons' to attempt pollution control standards for 1979, compared to the ADFA. It's a far more complex carburetor. I have more info/pics/diagrams on the ADHA and it's connections,...
If you do not attach vacuum to the distributor's vacuum canister, your timing advance at throttle will be retarded, compared to where the car's ignition was intended to run. This will affect your timing, and emissions.
Some distributors are designed to centrifugally advance timing, but the stock Fiat distributor is not. If your's has a 'can' on the outside, it needs vacuum to operate properly.
All of this is assuming that your timing is set properly,...!

[kbolden]

Correct, it is an ADHA - I have no idea why I called it an ADFA - probably just had that on my mind because it is the only carb I can find drawings for.

I'll drop you a note offline - if you have photos and markings, it would be HUGE as I'm totally unclear about the add-on ports, and that is causing me to not understand whether I've got the lines running to the wrong spots...

[wetminkey]

I have the exact same carb, with the original colored port 'rings' that indicate what emissions hoses go where,...and the colored hose complex that goes with them. I also have a Fiat Shop Manual and some schematic diagrams that I've collected over the years. I JUST got done rebuilding, and adjusting, my ADHA completely,...so I probably have the info you may need to get your's working properly. I'll be happy to share!
PM me here. I'd post my email, but I think SPAMMERS are using this site,...
Todd.