Test 4 - TPS Wide Open Throttle
- Ground terminal A on ALDL with engine idling. Connect dwell meter (6-cyl. scale). Warm engine until dwell starts to vary.
- Connect jumper between ECM terminals No. 5 and 22 and note dwell. See Fig 1
. Dwell changes to less than 20 degrees, go to step 3). If dwell does not change, check ECM connector or replace ECM.
- Remove jumper wire. With ignition on and engine off, check voltage from ECM terminals No. 5 to 22 while depressing accelerator pedal. If there is no voltage, go to step 4). If voltage decreased from greater than 3 volts (idle) to less than 3 volts (wide open throttle), perform SYSTEM PERFORMANCE CHECK
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- If voltage is greater than 6 volts, go to step 5). If voltage is less than 2 volts, go to step 6). If voltage is between 2-6 volts, check TPS assembly.
- Repair short to battery wire to ECM terminals No. 5, 7 or 22.
- Check open wire or grounded wire to ECM terminals No. 5 or 7, if okay check TPS assembly.
Courtesy of GENERAL MOTORS CORP.