1993 Isuzu Truck CARB

JOEOEARTH

MEMBER
1993 ISUZU TRUCK

Engine Mechanical problem
1993 Isuzu Truck 4 cyl Two Wheel Drive Manual 240 K miles

I do not drive this vehicle but start it a few times a month, recently it did not want to start so I made sure the gas and oil levels were good, charged the battery and still no ignition. I primed the carb with gas and it started for a few seconds but shut off, I disconnected the fuel line to the carb and turned the key and pressed the gas pedal and saw gas coming out, reconnected the fuel line and turned the key and pumped on the gas pedal but did not smell or see any gas in the carb. Is there something between the gas inlet to the carb and the actual carb barrell that may be plugged or am I looking in the wrong area? Thanks

1 Reply

DAVE H

MECHANIC
13,383 POSTS

Hello. And thanks for the donation. Much appreciated. Hope this helps. Let me know

FUEL DELIVERY
Fuel Pump
All models use engine-mounted mechanical fuel pump with internal check valves. Fuel pump push rod is driven by camshaft lobe.
FUEL CONTROL
All models use a 2-barrel Stromberg style downdraft carburetor with mixture control (duty) solenoid, automatic choke and piston-type accelerator pump. Carburetor integrates low speed (primary) and high speed (secondary) barrels, while using a common fuel bowl. Idle speed is set with idle speed screw. An evaporative fuel system keeps fumes from venting to the atmosphere.
Automatic Choke
The automatic choke uses an electrically heated, bimetallic element to control choke valve opening. Choke element is powered through choke relay.
Fuel-Cut (Slow-Cut) Solenoid
Solenoid decreases fuel delivery during deceleration. It also prevents engine overheating and after-burning in exhaust system. ECM uses idle (vacuum) switch and MAP sensor signals to control fuel-cut (slow-cut) solenoid. See IDLE (VACUUM) SWITCH and MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR under INPUT DEVICES.

Idle (Vacuum) Switch
The idle (vacuum) switch provides ECM input signal. ECM reads idle (vacuum) switch and MAP sensor signals to determine idle, part throttle and WOT conditions. ECM uses these sensors to control fuel-cut (slow-cut) solenoid.

Manifold Absolute Pressure (MAP) Sensor
The MAP sensor reads intake manifold pressure changes with reference to zero or absolute vacuum.