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Hammer Time
Hammer Time, L1 Master Technician
Category: Car
Satisfied Customers: 4942
Experience:  ASE Mastertech with Adv level Engine performance cert.
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how do I adjust the ignition timing in my 94 S10 Blazer

Customer Question

I recently got a Blazer from my brother, he said he couldn.t figure it out, the truck has been eating gas like crazy, like 10mpg to be exact, it's a 1994 S10 Blazer with a 4.3 vortec v6 motor we changed the plugs, and checked to see if all plugs were firing, ouch... I got shocked a few times, but the weird thing is, when I do try to take off with it, acts like it chokes out, kind of like it's running on 5 cylinders but when it shifts into 2nd gear it drives fine then, we changed the 02 sensor and even ran without the cat converter for a while to see if that was the problem I'm stumped, HELP?
Submitted: 9 years ago.
Category: Car
Expert:  Hammer Time replied 9 years ago.

Is the check engine light coming on?

How many miles on the truck?

Customer: replied 9 years ago.
Reply to Hammer Time's Post: yeah the check engine light is on, but I don't know the milage, there is a weird short in the all digital dash.
Expert:  Hammer Time replied 9 years ago.

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) or "Service Engine soon". 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 way to manually retreive codes from your truck.

Once you have retreived and recorded them, disconnect the battery to clear them and run the truck again to see what codes if any reset.

Diagnostic Trouble Codes - 1994

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)

The ALDL diagnostic connector is located in the passenger compartment.