Carbourater questions

[VanHalen]

O K I'm no mechanic by any means, with just basic mechanical knowledge. I do know that a Carb is way less electrical than fuel injection. So I guess the question is, on my 84 s10 blazer, adding HHO may improve performance, but would it really improve MPG without some kind of adjustment to the gas flow in the carb? The HHO can mix with the gas easy enough, but what is stopping the gas from continuing to flow at the same rate as before

[Griz64]

On your engine which you said is an 84 unless it has been replaced, you will have to adjust the jets on the carb to run leaner (less gas). My suggestion would be to find the correct screw on the carb (look in a manual) and slowly tighten it until the engine begins to stumble then back it off 1/4 of a turn--hook up you HHO and test it out..it should be fine but if its not then back off the screw another 1/4 turn...etc. Hope this helps.

[Cadillac]

If your carburetor is stock then it is ran by the GM computer command control (CCC) system. The main advantage of this system is its use of the (M/C) mixture control solenoid. The system functions in five distinct ways.

1. Shutdown mode - When the engine is less then 200 rpms or battery voltage is less then 9 volts the system goes into shutdown mode. This ensures that no voltage is supplied to the M/C solenoid.

2. Start-up - This provides a stronger then normal signal sent to the M/C solenoid to provide the engine with enrichment. The length of this enriched state is determined by the coolant temperature sensor. This mode overrides the next two states.

3. Open-loop - This is the mode where the engine and oxygen sensors are warming up but have not achieved proper operational temperatures.

4. Closed-loop - This when the engine and oxygen sensors have reached operational temparatures (the system will also wait a predetermined amount of time before going into closed loop). Some vehicles with this system will switch back and forth between closed-loop and open-loop mode because the oxygen sensor can cool at idle if allowed to do so for a couple of minutes.

5. Enrichment - This occurs regardless of whether the computer is in closed or open-loop mode when the throttle is at or near WOT. The computer will send steady voltage to the M/C to achieve this state.

The CCC system of course attempts to achieve the stoichiometric ratio as best it can.

Some flaws in the system are the oxygen sensors. These are the most simplistic systems on the market. They compare the outside oxygen content with the oxygen content inside the exhaust pipe. The good old "water4gas" covering of the sensor will give you room to work with in terms of leaning on these type sensors. This will also allow the oxygen sensor to warm up faster and hopefully not allow it to cool off enough to go into open-loop mode during normal driving conditions.

Another way the computer can go into open-loop mode is when a heavy load is place on the vehicle, going up hills, WOT...etc... The engine requires a richer mixture. The CCC determines this by using the MAP sensor. This is another area you would want to tamper with in order to go leaner. A very simplistic potentiometer interupting the signal set quite conservatively would be enough.

The M/C solenoid was always the weakest link of these system designs. The computer could function way faster then the solenoid could respond. Sending 10 pulses a second the M/C would always be playing catch up to the actual demands of the computer (this why they were dropped in lue of fuel injection). By munipulating the above to in a very conservative way it would be possible to achieve the leanest mixtures of the factory determined presets. The richest it should run from the factory is 13:1 and the leanest it should run from the factory is 18:1. These are set by two screws the lean mixture screw and rich mixture screw. Neither of the two is easy to mess with on these carbs (dualjet, varajet, or quadrajet). Probably do more harm then good if you don't know what you are doing when adjusting these.


I guess the short version of my response is that you will still have to use similar methods as fuel injection because of the year of the vehicle. Anything before 81' (or 80' in california) would for the most part be way more simplistic (except some cadillac and oldsmobile) in terms of GM automobiles.

On the bright side these systems are easily overriden with very little money, know how or exceptional safety/reliability concerns as in later model vehicles.

[VanHalen]

OK thanks for the info. So basically I need to lean out the MAP and not let the o2 senors cool down using aluminum foil untill they match the output from my HHO cell? By match I mean truck runs well.