JW454NOVA
Newbie
Working on a customers 1989 Grumman Kurbmaster with a 5.7 350 TBI. Came into the shop running rough and dying. Pulled up scanner data and found CTS showing -40 KOEO. CTS comes up to maybe 30-40 degrees when the truck is running and RPM'S are up. Goes slowly back to -40 and then dies at idle. TPS voltage does not change whatsoever (2.56 volts). Battery voltage showing 1.7 volts through scanner. Using the snap on brick. Truck keeps flooding out due to funky sensor readings. Unplugging the CTS sensor doesn't change anything.
Component's replaced and repaired ~
- Coolant temp sensor and pigtail replaced
- Thermostat ground eyelet replaced
- Ground cable (back of head to frame) replaced
- ECM and PROM chip replaced
- TPS replaced
- Fuses are good
- Checked wiring harness from sensors to ECM
New temp sensor ohms out at 1700 ohms. What am I missing? Is there another ground for the ECM somewhere? Truck is charging at 13.6 volts. Is there any possibility of a bad alternator diode causing the sensors to act up? Any input would be much appreciated. Thanks.
Component's replaced and repaired ~
- Coolant temp sensor and pigtail replaced
- Thermostat ground eyelet replaced
- Ground cable (back of head to frame) replaced
- ECM and PROM chip replaced
- TPS replaced
- Fuses are good
- Checked wiring harness from sensors to ECM
New temp sensor ohms out at 1700 ohms. What am I missing? Is there another ground for the ECM somewhere? Truck is charging at 13.6 volts. Is there any possibility of a bad alternator diode causing the sensors to act up? Any input would be much appreciated. Thanks.