Carb Sync

[oliverjb]

I have a 2k I/S with 110k mi. I had a popping on decal and attempted to do a carb sync. I have home made manometer 35 in tall. I have used this in the past and it worked fine, however now I have a number of lines that pull more than the 35 in and I have ATF running into the cylinders. The #3 is one of them that is pulling over the top. I'm lost on where to start . I have tried from 2 turns out op to 5 turns out. Where do I start.

[oliverjb]

I did a desmog in 2004

[Patrick]

If you haven't had a problem in the past and now #3 is pulling to much, how could you try and adjust the others ? What is your engine speed ? Try and lower it.

[oliverjb]

Engine speed is steady at about 850-900 rpm

[pocobubba]

sync the idle screws not the air /fuel

[Grandpot]

Make sure there is no way for air to enter into the manometer. If any air enters the system, it will allow the fluid to be sucked into the carbs.   It MUST be a closed system.

[pancho]

And not only does the system need to be closed, but the reservoir need to be completely filled with fluid. The more air that is in the reservoir, the higher the fluid will travel in the tubes,, if there is no air in the system, and you have a complete vacuum, the ATF will only rise about 18 inches in the tubes. The more air, the higher the rise.

[oliverjb]

The system is completely closed but maybe I need to make sure the reservoir is full. Thanks I will let you know how it goes.

[Patrick]

Just for the heck of it, have you tried a plain old every day vacuum gauge ? It might be interesting to see it had to say.

[BlueValk]

Make sure there is no way for air to enter into the manometer. If any air enters the system, it will allow the fluid to be sucked into the carbs.   It MUST be a closed system.

I'm sure that it is an "open" system.  At least my mercury gauge is.  In support of this, if you have 3 instead of all four (or 5 vs 6) vacuum hoses hooked up, the gauge should still work.  By leaving the one open, you now have an open system.  We are not trying to stretch the fluid (closed system), but weigh it against the vacuum.

Try buffering the tube with hemostats or something.  Maybe it is surging too much.

[oliverjb]

I finally went out and bought 2 vacuum gauges and synced the carbs but I still have a slight pop on decal and seems to be from one carb on the right side. I may just leave that way for now unless someone has another idea. Thanks

[pocobubba]

Intake "O" ring or Exhaust gasket

[salty1]

I finally went out and bought 2 vacuum gauges and synced the carbs but I still have a slight pop on decal and seems to be from one carb on the right side. I may just leave that way for now unless someone has another idea. Thanks

How many turns do you have on your pilot screws? Try 2 1/2. Also as said above make sure that there are no air leaks. FWIW, these beasts will pop some on decel at times. It helps a lot to make sure the carbs are synched properly. It's just their nature to snort and fart. 

[Patrick]

These monsters will 'burble' on decel especially if exhaust mods have been performed. I guess it depends on ones definition as to when a 'burble' becomes a 'pop'. 

[pancho]

Make sure there is no way for air to enter into the manometer. If any air enters the system, it will allow the fluid to be sucked into the carbs.   It MUST be a closed system.

I'm sure that it is an "open" system.  At least my mercury gauge is.  In support of this, if you have 3 instead of all four (or 5 vs 6) vacuum hoses hooked up, the gauge should still work.  By leaving the one open, you now have an open system.  We are not trying to stretch the fluid (closed system), but weigh it against the vacuum.

Try buffering the tube with hemostats or something.  Maybe it is surging too much.

You must remember that the mercury in your gauge has a much higher specific gravity (density) than ATF,, while the mercury will work as an open system, the ATF gauges will not unless they are about 12 feet tall.

Oliverjb, also, if you still have your smog system in place and there is no vacuum being applied to the PAIR control valve when you let off the throttle, (leaking or missing vacuum hoses on #3 and 4, or a leaking PAIR control valve) it will continue to draw air  into the exhaust at closed throttle and can cause popping.

[pancho]

Never mind on the smog system,,, I see you said you did a desmog.....  if you can pinpoint the cylinder, do all steps to cure a lean condition, check intake o ring, vacuum cap, check carb to intake clamps..... maybe run some b12 through it to help clear out the slow jets.