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Chevy man
Chevy man, Chevy Technician
Category: Chevy
Satisfied Customers: 4942
Experience:  ASE Certified as an L1 Master Technician with extensive experience in Chevy products
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I have a 1993 Chevy Suburban. When the engine warms up, the ...

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I have a 1993 Chevy Suburban. When the engine warms up, the fuel burns rich and dies at an idle and will not start up again until the engine has completly cooled down. If I do try to start it when it is hot or warm, the engine is not getting fuel. I have changed the O2 sensor and the module under the rotor. Please advise.

Which engine does it have?

Is the check engine light coming on at all?

Customer: replied 10 years ago.
Reply to Chevy man's Post: Once the engine has warmed up, yes the Check Engine light does come on. Also, I forgot to mention that I have by passed the Calalytic Converter this past fall. Thank you.

The check engine light is a warning light that comes on if the computerized engine control system detects an engine performance or emissions problem. Also called the "malfunction indicator lamp" (MIL). It can come on for any of hundreds of different causes from any of the systems that the computer monitors. Some are very important and some not as serious.

Your first step is to have the computer scanned to retrieve the trouble codes that were set when the check engine light came on. Those codes will get you pointed in the right direction to find your problem.


Here is a method to manually retreive the codes on your vehicle.

Diagnostic Trouble Codes - 1993

13 Open Oxygen Sensor Circuit
14 Coolant Temperature Sensor (High Temp Indicated)
15 Coolant Temperature Sensor (Low Temp Indicated)
21 Throttle Position Sensor (Signal Voltage High)
22 Throttle Position Sensor (Signal Voltage Low)
23 Manifold Air Temperature (MAT) Low Temp Indicated
24 Vehicle Speed Sensor (VSS) Circuit
25 Manifold Air Temperature (MAT) High Temp Indicated
32 Exhaust Gas Recirculation (EGR) Circuit
33 Manifold Absolute Pressure Sensor Circuit (High Sig.)
34 Manifold Absolute Pressure Sensor Circuit (Low Sig.)
35 Idle Air Control (IAC)
41 Cylinder Select Error
42 Ignition Control (IC) Circuit
43 Knock Sensor (KS) Circuit
44 Oxygen Sensor Circuit (Lean Exhaust Indicated)
45 Oxygen Sensor Circuit (Rich Exhaust Indicated)
51 EEPROM or ECM Failure
53 System Voltage Overcharge
54 Fuel Pump Circuit (Low Voltage)
55 ECM Error
61 Degraded Oxygen Sensor
62 Transaxle Gear Switch Signal Circuit
63 A/C Refrigerant Pressure Sensor Circuit

To extract a trouble from the computer for diagnostic purposes, the Assembly Line Communication Link (ALDL) connector is used.

Ground terminals A and B with the ignition "ON" and engine not running. The system will enter the diagnostic mode. In this mode, the computer will display a 12, three consecutive times, by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" or light. A 12 consists of one flash, a short pause, then two flashes in rapid succession.

After 12 is displayed, any stored trouble s will be displayed by flashing the "CHECK ENGINE", "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR LAMP" light. All s are displayed 3 times each then a 12 will repeat. In the diagnostic mode, the computer will also energize all computer controlled relays and solenoids.


ALDL Connector (Located Underdash)
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