Troubleshooting a 1987 Dodge Ram 50 Carburetorby John Walker
The 1987 Dodge Ram 50 uses either a four- or two-barrel carburetor. The carburetor mixes air and fuel in appropriate levels prior to injecting the mixture into the engine. Whether your vehicle uses the stock carburetor or an aftermarket one, the problems that arise are the same. Troubleshooting these issues requires some basic monitoring of your vehicle's performance, identifying what issues exist and what they mean. A common misdiagnosis of a carburetor problem is actually dirty fuel. Problems that continue beyond refilling the fuel tank need further diagnosis.
Start your vehicle. If the engine will not start or turn over, you have a blocked fuel line. Check the fuel line delivery system. If the engine starts but dies immediately or after a few seconds, the choke may not be closing or is set improperly. Other signs that the choke may be set wrong include the vehicle dying at low idle or revving high and then dying. If, after starting, it revs up high and stays high in park or neutral, the idle is set too high.
Run the vehicle for 15 to 20 minutes. After running it for a few minutes, if the RPM remains high and there is a lot of black smoke or the engine dies, the pull-off diaphragm or power valve may be damaged. You could also have a serious vacuum leak in the lines or carburetor.
Turn the vehicle off and restart it. If you are unable to restart the vehicle after it has warmed up, the choke may be staying closed when the engine is hot. If it dies after a few seconds, the power valve or venting system is inoperative.
Drive the vehicle after the engine has warmed up. Hesitations or stumbling with light throttle indicates a vacuum leak, bad accelerator pump, damaged idle solenoid, a stuck heated air inlet or a stuck EGR valve. Black smoke or choppy running indicates a blown power valve. Hesitation or dying under heavy throttle points to a bad accelerator pump, stuck metering rods or a power valve, or the secondary air valve is set wrong. If the truck is idling fine but dies when stopping, you have a bad throttle positioner or defective float.
Turn the vehicle off and allow it to cool. Once the engine has cooled down, start and immediately drive the vehicle. Engine stall, when engaging the transmission, indicates the choke pull-off or fast idle is set too low, or there is a potential vacuum leak. Stumbling or hesitation, while driving, points to a vacuum leak or improperly set choke. It could also mean the vacuum tubes are hooked up incorrectly. Hesitation or stalling, after the vehicle has been driven for a short time, indicates a defective electric assist, accelerator pump or ignition condenser. Backfiring from a cold engine implies a plugged heat crossover system or a defective heat shroud duct or manifold vacuum supply.