Hc 5000 tank over flow any ideas'''

Only a guess but I would check the return lines for a pinch or clog. My Simi would not balance flow due to a line that was not made correctly. Sounded like the same symptoms

Is the fuel flow strong at the injection pump ? If not you may have a partial blockage inside the tank, wouldn't hurt to change the fuel filters either. I had a similar problem with my 350 JD dozer
I checked the tank and found some debris covering the outlet hole,
debris removed problem fixed.
Also check all your fuel lines, if all the above is good, than start cracking each injector one at a time with the machine running
as long as it will run, you will notice a bad injector by the difference in sound , a good injector will cause rough idling l a bad one will not.

Mass air flow or computer.

get your injectors cleaned. change the air filter .change your plugs. put a fuel cleaner in your fuel tank.

MAP sensor needs cleaning or is bad ?

If you have an oil level switch on this generator, it could be that you have low oil level or the switch is bad. Check the oil level. Bypass the oil level switch.

How old is the fuel in the tank, and how full is the tank? Fuel goes bad with time due to the ethonol turning to gummy varnish like substance. Not keeping a tank full allows condensation to form on the inner walls, contaminating the fuel with water. Drain the tank completely and fill with new gasoline.

How did you "clean the carb?" If it was not completely disassembled, soaked in carb cleaner, and all jets and ports blown out with air, you could have blockages from the "bad gas."

BigDaddyPat

First make sure you have fresh gas in the tank, as old gas can cause a 'no run' condition. Once you have fresh gas in the tank, make sure the gas flows freely all the way to the carb by removing the fuel hose from the carb inlet & checking for good flow (bad shut-off valve or obstructed hose by debris could cause same problem). Once you are sure that good, fresh gas is going into the carb w/o obstruction, remove the lower bowl from the carb - carefully - do not lose ANY parts, starting with the washer on the bolt. With fuel flow 'ON', fuel should flow freely when this bowl is removed, so shut off fuel valve in the hose. Now, if you carefully remove the bolt / brass tube from the center of this bowl area (center of plastic float) - remove bolt downward, like you would a lightbulb from the ceiling - this bolt should have several holes in the side, they are probably clogged, so unclog them with a needle or wire, wipe clean, and reinstall. That probably just solved all your problem.... if not, you likely will want to replace the carb completely, as it is not very expensive, and will surely solve your problem. *** Be careful with gas fumes !!! ***

As I recall, only one filter. Big can under the hood next to the CIS air flow meter. Other than that, just the screen on the fuel pump pickup in the tank.

You did not post the odometer reading on the van but base on the year it should has over 85,000+ miles on it.

The most likely source of the high Hydrocarbon (HC) is clogged or drippy injectors.

Change the fuel filter if it is over 48K miles.

Ran two or more tanks full of Chevron gas will help clean out the fuel system.

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The air fuel ratio can be off is the air filter is clogged or the mass air flow sensor give incorrect data to the computer (ECU).

Change the air filter is it over 20,000 miles or you can see sunlight though it.

Use CRC Mass Air Flow cleaner or electronic part clean to gently clean the mass air flow sensor.

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Change the oil to 20W50 or one grade higher to prevent blow by.

You current motor oil is soak with HC from blow by.

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Make sure the tires are at 32 psi

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Do the smog test is a COLD morning?

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REMOVE excess cargo off the van.

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These are little things that I would do.

If the HC is still high at 25 mph then you will need a professional fuel injector cleaning or replace the injectors.


Please post more data on the third smog test on the comment window.

Do an oil change with 20W50 oil (or one grade higher) to prevent blow by during the test.

You current oil has HC from blow by though the rings.

Do a fresh oil change will lower the HC.

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Change spark plugs,wires,cap and rotor if they are over 24,000 miles
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Make the smog check appointment for the EARLY MORNING. Colder air will help the fuel burn better.

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Clean or change the air filter and pcv valve.

Clean Mass Air Flow sensor with CRC Mass Air flow cleaner or electronic part cleaner.

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Do a quick wipe down on the wires and cap to take the moisture off.

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Check spark plug wire contacts for corrosion.

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Fill the tank to around 3/4.......just in case your fuel pump is weak.

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Ran the truck for 20+ minutes on highway before the test.

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Do not carry excessive cargo on the truck bed.


These are the little things I would do to get the HC and CO down.


Please post more information on the comment window.