Tach and safe light....
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Junior User
Joined: Mar 2003
Posts: 90
Likes: 0
Tach and safe light....
Hi all, My '93 F-250's safe light(the OD light) flashes and the tach doesn't function unless rpm's are brought up right after I start it in the morning. This doesn't occur at any other time after I drive about two miles. At the end of the day at the jobs sites it also doesn't occur.
The safe light goes out and tach operates when the engine rpm's are at 1200. I haven't hooked it up to the code reader yet, any ideas before I go to that expense? All fluids are new and and full..not over full. New throttle position sencor with updates was installed recently as well as a new injector pump and the truck runs like new at 203,000 miles, this is the only problem.
The safe light goes out and tach operates when the engine rpm's are at 1200. I haven't hooked it up to the code reader yet, any ideas before I go to that expense? All fluids are new and and full..not over full. New throttle position sencor with updates was installed recently as well as a new injector pump and the truck runs like new at 203,000 miles, this is the only problem.
Senior User
Joined: Feb 2003
Posts: 315
Likes: 1
From: Alabama Gulf Coast
Tach and safe light....
Check your RPM sensor. It's located on the Driver's side of the I.P. housing below the oil fill spout. End is hex shaped with two wires coming out of it.
To check RPM sensor:
1. Remove 2-wire connector end.
2. Hook DVOM meter leads to sensor pins. Doesn't matter which way.
3. Set scale to AC voltage, 0 to 40 voltage scale.
4. Start engine in park. Raise RPM while watching DVOM.
5. Voltage must increase or sensor is bad.
R.A.
To check RPM sensor:
1. Remove 2-wire connector end.
2. Hook DVOM meter leads to sensor pins. Doesn't matter which way.
3. Set scale to AC voltage, 0 to 40 voltage scale.
4. Start engine in park. Raise RPM while watching DVOM.
5. Voltage must increase or sensor is bad.
R.A.
