Engine/Transmission (1994 - 1998) Help!-In diagnosing a electrical problem

[Breed]

1997 12 Valve, 185,000 miles, Went to start truck and dash gauges didn't work, wont charge and the transmission lock up and overdrive don't work. We changed the computer and cleaned the crank sensor and it didn't help. I sure would appreciate any diagnostic help with this problem. Thanks,

Breed

 

[McCRam]

When the crank sensor goes out, the computer won't turn on. When mine went out, I couldn't even scan the pcm. However when I unpluged the crank sensor, the computer would then turn on and the grid heaters would cycle. The sensor also needs to be set a certain distance from the crank. I can't remember how much, but I found it here on these forums. It needs to be set with a brass feeler gauge. You should also check the connector for the sensor before you replace it. Its is by the #1 valve cover if you haven't found it yet.

 

[Breed]

Thank you McRam so much...

Breed

 

[Andy Redmond]

. 052



Don't adjust over one of the notches in the vibration damper.

 

[K5IP]

Does your tach work? If it works, your engine speed sensor is OK.

If the tach does not work check the wiring connector the sensor feeds. It is located just above the sensor. (big source of problems)

Just for information, the sensor has three leads, 1. a refference supply voltage of about 8vdc from the computer, 2. a signal out line which switches between zero and eight volts each time a notch in the vibration damper appears. and 3. ground.



Good luck

Rog

 

[Kirwin]

Check for burnt fusible link

There is a fusible link that supplies power to the transmission OD circuit. The PCM just grounds the return side to achieve lockup. Ken Irwin