Why does engine run rich at times under acceleration?

Engine coolant temperature sensor reading too cool causing rich mixture or oxygen sensor reading lean causing a rich fuel pulse . Oxygen sensors come into play as engine warms up and goes into closed loop .

Ahhhh..the Sporty has a rattle...or is it a ping? If your popping through the exhaust, the timing could be off and running rich (Check Spark Plug for dark sooty layer) If your engine is pinging could be advanced timing... pre-ignition happens on acceleration or under a load...loose valves will make noise all the time

Do you have the CV Keihin still? Or are you running an aftermarket carburetor ? Like an S&S?

When the engine really got hot is there a possibility you may have over expanded some parts and now the engine is sort of tight and is not spinning fast enough to start.

Check for spark and fuel delivery but ......................

what kind of smoke by that I mean what colour is it and when does is happen under hard acceleration, at idle, when first started, under light acceleration, idling a long time? blue smoke is burning oil, white smoke is burning coolant sometimes accompanied with a sweet smell, black smoke its running rich. those are the basics.

check the HO2s and HO2 sensors as the tuning of the engine is out because of erratic sensor messages to the ECM. Misfires can also be from faulty injectors or low fuel pressure in the fuel manifold . The rattle under acceleration will be detonation from a problem with the air/ fuel / timing because the ECM is not getting constant readings from the sensors to be able to adjust everything

Sounds like your fuel pump starting to die. It is not getting enough gas under heavy acceleration which is 100% fuel pump slowly dying. At start up it might not be building up enough fuel pressure to feed the system but the shot of ether and engine cranking helps pressure the system just enough for the fuel pump to trickle the gas and run the engine at low rpms.

You are off to a good start, MAF when it is contaminated it leans the vehicle out it doesnt make the car run rich, depending on the fuel strategy of the year make and model,and of course the engine size make all the difference,bad ignition coil make a car run rich shorted 02 sensor that lean bias make the car run rich, worn timing belt ****** timing and causes the car to run rich.so lets hear the results

DTC P0172 - P0172 Fuel Trim System Rich Bank 1... this indicates that the fuel mixture is too rich, but you already know it is running rich.

A rich fuel mixture can be caused by a number of things First, I would suggest checking fuel pressure to make sure it is within normal specs If fuel pressure is too high due to a faulty pressure regulator for example, it will cause too much fuel to be entering the engine.

A leaking fuel injector can cause a rich fuel mixture, as can an injector that is stuck in the open position. When the engine is shut off, monitor fuel pressure with a fuel pressur gauge; it should remain steady.If fuel presure drops when the engine is off, then removing the fuel rail and injectors while still connected to the lines to visually check for a dripping injector may be informative.

There are several engine control system problems that can cause a rich fuel mixture; if you can obtain a scan tool that is capable of displaying live engine data you can check for these possible causes:

1) Low MAP reading; this can be due to a fault in the MAP sensor, MAP circuit, or as a result of low engine vacuum due to a restricted exhaust, jumped timing belt, or low compression on one or more cylinders caused by valve leakage or a leaking head gasket. Compression testing the engine may reveal internal mechanical problems of this type that would cause low engine vacuum. A low engine vacuum reading from the MAP makes the computer think the engine is under heavy load such as during acceleration, so it commands a rich fuel mixture in response. A vacuum leak can also result in a rich mixture for the same reason.

2) Low coolant temperature signal. This can be caused by a fault in the coolant temperature sensor circuit, faulty coolant temperature sensor, low engine coolant level, or a faulty thermostat that is allowing the engine to run too cold.

Keep us updated.

Engine Smoking:
.
Black Engine running rich Possible Failure
-Map sensor, fuel injector or fuel pressure regulator.
Blue -Replace Faulty Transmission modulator valve
White Possible Failure. -Head gasket.
Hope this tip helps.
r/
David

It's the automatic choke!

The choke is "closed" or barely open... When cold, the engine needs a RICH mixture (more gasoline, less air). When the engine warms up, it requires a LEAN mixture (less gas, more air).

It is probably creating BLACK tailpipe smoke ... that means unburnt gasoline. (Blue smoke is OIL, white smoke is WATER).

Put the parking / emergency brake ON.
1. Remove air cleaner assembly from intake, use a carb cleaner spray or throttle body spray cleaner and spray just a little. (AutoZone $5)
2. Find the accelerator arm under the hood.
3. start car, rev the engine to make sure how to operate the accelerator from under the hood.
4. Carefully spray into carb / throttle body and work the accelerator ... don't let the engine die...
5. Watch out for "backfire"... it may create a small flame out of the carb. It will extinguish itself in one second.

6. You may need to do this two, three times.
7. Add a "complete fuel system cleaner" to your next tank of gas ($8).

That's it! ... pretty cheap, too.

Hope this helps!