Carb spitting up

[architect]

I doubt that the cam timing being off by one tooth would cause your problem, either exhaust or intake cams or both. In fact, in my younger (more foolish) days, I played with the cam timing one tooth in either direction to see if I could extract any more performance out of 1438 cc. Short answer: No.

If your timing belt has even a little bit of play in it, you could be off by 1/8" or so on the cam timing marks. With the cam timing marks lined up and transmission in neutral, see if you can rotate the crankshaft at all by hand. If so, you may need to release the lockdown nuts on the timing belt tensioner pulley and make sure it's pulling the belt taut. Retighten after correcting, of course.

If a lot of hoses have been removed or capped off in the intake system, that could be affecting your air/fuel mixture which could lead to some issues. Let us know through pictures or descriptions what you have going on here.

-Bryan

Pics of timing below, looks dead on!

Also I only have one port on the carb blocked off, see picture below too. All other ports on intake manifold and head blocked off.

Going to check if gas is pouring into carb tomorrow.. I can confirm it’s not the throttle cable holding it open.

[18Fiatsandcounting]

Let us know how it works out. On the carb, I have to admit that I've had so many different carburetors that it's hard for me to remember all the vacuum ports and their functions. I'm thinking your car had an EGR setup, and perhaps the port that you circled in yellow is the vacuum control for the EGR? Almost all of my Fiats have been before significant emission controls, but I vaguely recall that the exhaust gas is only fed back into the intake manifold above a certain RPM, hence the need for a vacuum line that is RPM dependent.

In any event, see how the engine runs, and if you have a vacuum gauge (or your finger), you could connect it to that port and see what kind of vacuum you have and under what throttle conditions, and that might give some clue as to whether just capping it off is OK.

-Bryan

[architect]

Also, as of now I have the vacuum “tee” capped off, this is the fitting that screws into the intake manifold and routes a vacuum hose to the brake booster. Should I connect this small tee to the carb vacuum? Or leave both capped?

Sorry for all the questions. I have worked on this car endlessly and very excites to put it back on the road.

[SteinOnkel]

My motto with such things is "simplicity is key". Unless otherwise mandated by your local jurisdiction, I would remove and delete any and all emissions related devices. For diagnostics, do the same and get the car running right. Then reconnect them one by one until you find the culprit.

[18Fiatsandcounting]

I agree with SteinOnkel's approach: Cap off all the vacuum ports, except of course for the large vacuum port that goes to the brake booster, and see how it runs. Almost all the other vacuum lines that I've run across either serve to "adjust" the operating parameters of the carburetor (such as the fast idle device) or are there as part of the emissions control systems.

While it might work to run vacuum tubing from one port to another, this approach also runs the risk of introducing vacuum into various parts of the carburetor when it doesn't call for it.

One other vacuum line that I've seen on older cars: the one that goes from the crankcase breather hose fitting on the air cleaner housing to the "throttle bypass valve" on the base of the carburetor. Going by memory here, but its purpose is to meter some of the crankcase vapors into the downstream side of the carburetor (i.e., into the intake manifold) under certain throttle positions. I've never noticed a big difference whether this system is working or not, but you don't want to have an opening for the crankcase breather system to vent into the engine compartment as the crankcase vapors carry oil droplets with them and you'll end up with oil on the carburetor side of the engine over time.

-Bryan

[architect]

Update:

I spent the afternoon on the following:
- triple checked the timing, I even made a compass, looks spot on.
- reset the Conputronix ignition
- confirmed, only one vacuum port on carb, it’s blocked
- only one wire to carb, on electric chock and works
- followed instructions from Redline.. made sure the idle adjustment was set, screwed in the mixture adjustment all the way, then backed out two rotations (I’m assuming this is a full 360 degree turn X 2)
- set timing

First start worked great but backfire a little. I turned the mixture screw a 1/4 turn and it eliminated the backfire. But seems too lean, notice when I rev the engine..

Yet the car feels like it’s running rich at idle, and too high RPM, like 1500. Ugh, I can smell it.. like a lawn mower. See video below, you can see the fumes coming from the vapor crank case vent on the carb filter. Ugh. Also comes out the exhaust, but it’s defiantly not that thick white smoke from a head gasket condition.

Calling it an afternoon. Need a beer after all of that, ugh!


https://www.dropbox.com/s/nr0g1h4dydva5 ... M.mov?dl=0

https://www.dropbox.com/s/sgain3b7sxaxl ... M.mov?dl=0

[architect]

Also, thanks to everyone’s suggestions so far!

[architect]

Oil is pure black.. had to check this before I retire for the evening. Maybe an exhaust bolt leaking into header? but that wouldn’t explain the PCV smoke?

[blazingspider]

I've got a 77 with the 1800, hi comp pistons, 40 80 cams, a facet fuel pump with no pressure regulator and a 34 ADF. I've got the later model fiat electronic dizzy installed instead of the old dual point that came with the car.

Warm restarts for me are always a bit harder to get the engine fired up as opposed to when the motor is cold. I've heard that today's fuel with ethanol can make warm starts on older carb'd cars harder. I've discovered that the best practice for me to re-start a warmed up engine is to slightly depress the accelerator pedal while turning over the motor and even then it still will crank longer before firing up as opposed to when the engine is cold.

As far as vacuum ports go you only need the one from the larger port on the tee on the manifold that goes to the brake booster. Everything else could be capped off for now.

I seriously doubt you have any issues with valve timing and that you know advancing ignition timing will increase engine idle speed. That being said I've got a few questions for you regarding your set up:

Where's your fuel pump located? Hopefully it's in the trunk down by the gas tank. Most Weber carbs like to function at around 2.5 psi and I think you set the fpr for that pressure so you should be good there.

How thick is that spacer between the bottom of the carb body and the intake manifold. The pic makes it look pretty thin. Mine's probably at least 3/8" thick. The spacer's job is to isolate the carb from the intake manifold so fuel won't vaporize when subjected to the higher temp of the manifold.

The weber redline carb tuning instructions are to be done on a fully warmed up engine. Was your engine up to temp when you adjusted the idle mix and idle speed? In one of your videos it sounds like the car started on the choke circuit and then kicked down either as the choke warmed up or you hit the gas pedal, the choke dis-engaged and the idle speed was set so low that the engine died.

Did you ever check the float level to ensure it is within specs? Webers are supposedly notorious for acting up if the float level is incorrect. To adjust the float level you have to remove the top horn of the carb. Whether you want to do that with the carb on the car or off on a bench is up to how comfortable you are. Once the top horn is removed, there are 2 float settings, one for when the needle valve opens to allow fuel into the bowl and one for shutting off the fuel flow when the bowl has fuel at the proper level. To adjust the float for when the needle valve opens to allow fuel into the bowl you hold the top horn horizontally and measure the drop distance between the top of the float and the underside of the carb horn. It should be around 14 mm. To set the float level for when the needle valve closes to stop fuel from entering the bowl, you hold the carb horn vertically until the tang on the float is just resting but not depressing on the ball of the needle valve. That measurement should be 7 mm. FYI both measurements are taken with the gasket in place on the carb horn. To adjust you just bend the tang on the float.

When the engine is running on the idle speed circuit and you peer down the carb throat, you should not see any fuel being expelled from either of the secondary venturis or the accelerator pump nozzle. If you see fuel on the primary side then you are running on the main circuit and not the idle circuit. If you see fuel on the secondary there is a little set screw for the secondary butterfly valve that is keeping it too open. You need to set it so the butterfly valve is just barely and I mean barely off the carb throat. Fuel from the accelerator pump nozzle should only be seen when rapidly opening the throttle and only then.

Regarding the misty oil smoke from the vapor separator hose. Do you have the flame arrestor installed in that hose? Have you ever cleaned out the oil vapor separator itself? They can get pretty mucked up and won't perform their function adequately and the flame arrestor will collect some of the oil in the vapor as it passes through it rather than send all that oil mist up into your air cleaner. That being said I really don't think it's all that bad from looking at your video.

Last but not least you don't have any vacuum leaks at the carb or the manifold right?

Good Luck!!

[architect]

Quick update (and better news!)

- I replaced the fuel pump. Went from Facet square to Facet gold. Wow what a difference in sound. The square pump started making funky noises and would go from loud to quite, vise versa. The gold is very silent and reads a constant flow. This is located in the trunk, right below the battery box. All stainless braided lines, new tank, sender, etc.
- Installed flame trap.. although I have an oil catch can installed too
- I also swapped out the carb spacer. Redline shipped a 1/4" originally, I then replaced with 3/4" from AR. Not sure if any benefit here.
- I also took my aluminum spark plug wire collectors off. Also not sure if there a benefit, but assumed it was cross firing?

I believe the reason the car started great cold, b/c the idle set screw was not engaging correctly. The fast idle set screw (on choke) was calibrated, but the actual idle set screw wasn't. Hmm. Not sure how that happened. Now the car starts up instantly... cold or hot start. YES!!!

Im also thinking the idle jets are too large. I'm having to pull back the mixture screw about 3/4 to 1 turn out. When dialing in (according to Redlines instructions.. im to dial in 1/4" turn at a time until stumbles / dies.. then back out 1/2 turn). It almost bottoms out to get the engine to stumble... It pretty much does nothing after I back it out further then 1 turn. I'm also getting a mega rich exhaust smell, which put a dark tint on my driveway curb. Currently that car idles around 8-900 rpm, but a little rough.

Now I'm curious if Redline set up the carb originally to complement the smog system? All of that is gone!

Air / Fuel mixture gauge is on its way (wideband).

My carb is set up as follows:
- Primary idle jet (60)
- Secondary idle jet (50)
- Primary Air jet (165)
- Secondary Air jet (160)
- Fuel pressure 2.5 lbs (Adjustable FPR)

Any advise on jetting? Which jet do I need to work on, primary? secondary? both? THANKS!

[architect]

Here's a fun video of my electronic exhaust cut-off from last night.. Ignore the dirty car!


https://www.dropbox.com/s/ds3r4zj1ie4yy ... M.MOV?dl=0
https://www.dropbox.com/s/o9x7z0h32g14l ... M.MOV?dl=0

[architect]

Yep she’s rich. That plug has maybe 30 mins of run time. Just ordered a range of idle / air corrector jets from Pegasus.. and wideband. I’m getting to the point of desperation. The car is crying to get on the road!

[architect]

Good news Update!!!!

- Installed AEM wideband with clamp on 02 sensor. Pretty straight forward.. used a 2 1/2" clamp from Shiftglow (Amazon), drilled a hole right after the Vick Auto header (2" downstream from collector). and plumbed up thru the firewall.
- Swapped a few series of jets. 55/45 seems to be the sweet spot. NO MORE WHITE SMOKE! And the car smells more normal (even without a Cat Convertor).
- Mix screw is 1 3/4 turn out
- Idle sounds very cool!
- Let the car run for about 30 mins, temp stayed around 180 on the dot. Not sure if my thermostat opened up.. I will need to burp the system next time (Allison alum radiator and all cooling replaced)
- Cranked the car several times through-out the day, no hesitation at all.

At idle, Im around 13.5 A/F. A little rich for now, but need to get on the road to really test it.

Interesting.. when I open the electronic exhaust cut-off, the A/F decreases about .50.. although the O2 bung is close to 18" upstream.

Next step is to bleed the new brakes (vacuum gun) and get on the road. The scary part is.. my first time to do all brake repair (including e-brake).. my driveway is close to a 10' drop over 40 feet distance... which then looks over a 100' drop (I live on a hill). We're going to hook the car up to a tow strap to make sure the brakes are in good working order... traveling down the driveway