OD light flashing no RPM

[mikey_3776]

Recently while driving my 93 f350 I noticed when I am coming to a stop the RPM hand stops working and the OD light off starts flashing. It olnly does it sometimes. The OD light off only flashes when the RPM hand stops working. However the second I start off from a stop everything is fine.

Does anyone know what could be causing this?

Mike

 

[94f450sd]

sounds like you need to take the tach sensor out and clean it or replace it.it is in the injector pump gear cover in the middle of the motor .its looks like a big bolt with 2 wires hanging out of it.

 

[chickiepickie]

Recently while driving my 93 f350 I noticed when I am coming to a stop the RPM hand stops working and the OD light off starts flashing. It olnly does it sometimes. The OD light off only flashes when the RPM hand stops working. However the second I start off from a stop everything is fine.

Does anyone know what could be causing this?

Mike

I remember reading something about this in the supplemental diesel manual for my truck. do you have the manual?

 

[mikey_3776]

94f450sd,

I will give that a try tomorrow. I kinda thought it might be sensor related.

chickiepickie,

I have the supplemental diesel manual I will try looking it over also.

Thanks for the replies!

I also have one other problem I noticed: The speedometer is not smooth. What I mean buy this is when riding at any given speed (i.e. 70 mph.) the needle bounces slightly not more than 2 mph. However it is a pain when I set the cruise control cause it truck is speeding up and slowing down with the bouncing needle.

Any ideas on this?

 

[94f450sd]

you may need to replace the VSS(vehicle speed sensor) or just clean it.it is located in the top of the rear end housing and has a single 10MM bolt holding it in.

 

[mikey_3776]

Speed Sensor

Is the speed sensor the same as the ABS sensor? Reason I am asking is I just replaced a sensor on the rear chunk. (It had a 2 wire plug on it)

Thanks,
Mike

 

[94f450sd]

it may or may not be.look at the drivers side of the tranny if 2WD/transfer case if 4WD where the driveshaft come out.if there is a sensor there that is the VSS,if no sensor than the one in the rear end is the ABS/VSS