Engine/Transmission (1994 - 1998) No Tach/or Charging and its not just the ESS needing adjusting. HELP!!!

[CAMperformance]

Here is what is going on. Have a 1995 5spd truck, took the head off and the Engine Speed Sensor did not get unbolted from the head and it pulled the connector end off of the sensor. So instead of buying a new sensor and being done with it. In the name of saving a couple dollars, used crimp connectors on the ends of the sensor and the ends of the engine harness. Now tach will not work and obviously will not charge.



This is what i think happened and would like some of you to back me up. In the haste of trying to get the truck together and not paying attention to what was being plugged in where. I believe source voltage on the sensor was mixed up with the reference. Would that be enough to toast the PCM?



I still show a good ground, and 5 volt reference, and 8 volt source getting to the ESS and I have tried two different ESS's with no luck. Should I be checking something else?



Also is their a way to get the truck to charge without the ESS hooked up. If I could get the truck to charge that would be good enough for the moment. Until I get a PCM or what ever is wrong fixed.



Thanks in advance

 

[DWeaver]

Here is my adventure with the wiring of an ESS and hopefully some answers.



https://www.turbodieselregister.com...998/234314-engine-speed-sensor-questions.html

 

[hsmith]

If you determine you need a PCM, give me a shout. That is, if one for a '96 manual is the same.

 

[Missouri Mule]

CAMperformance, I think that 8 volts is to much for the Engine Speed sensor. You should of been able to get new pins for connector.



In 96 Factory service manual the wiring diagram is showing that the corresponding wires(color coded) run from the ESS to the PCM.



Confirming DWeaver's link.



From 96 factory service manual

Sensor ground = black/light blue wire, K4 circuit, pin #A4 on PCM

Enigine Speed Sensor signal = Grey/black wire, circuit K24, pin # A8 on PCM

5 volt supply = violet/white wire, circuit k6, Pin # A 17 on



The PCM should not be sending the sensors more than 5 volts. The sensors (ESS... ) should not be able to send more than 5 volts back (probably a lot less).



Unfortunately I don't have the "Powertrain diagnostics procedures manual" so I don't know what voltage is a allowable.