Engine/Transmission (1994 - 1998) tachometer failure, intermittent

[GClare]

1997 4x2 HD, Gear Vendors O/D, Towing for museum under 12k lbs normal driving back and forth to work. 131000 miles jacobs brand brake added, fuel filter relocated, no other mods. Intermittent Tach at speed from 1700rpm+ ? to zero and back up, no other signs engine runs fine no sign of stalling.

 

[Woodenhead]

Welcome

First post eh! Let me be the first to say welcome aboard.



Had the same deal with my tach. I pulled the plug off of the crank position sender and blasted the sender and the connector off with electrical contact cleaner. No problems since (35k miles ago). Some guys have had to replace the sensor. I remember a post about this a while ago and did a search. here , here and here are some posts that may help. Do a searce for tach or tachometer and you'll find tons of good info.



Take it easy

Mike

 

[Overprice]

Having same problem.

Is the CPS a dodge part only?

Thanks,

overprice

 

[Desperado]

As far as I know it is a dealer only part, easy to replace youself, mine did the same thing a few years ago, replaced it and all is good. Welcome to you both.

 

[K5IP]

Clean the sensor connector first. They sometimes fail at high engine speeds because the fan is blowing directly at them. I had to wire my connector together with wire ties (after cleaning) to make a good electrical connection. The connector in question is located just above the ess sensor (engine speed sensor).

Rog

 

[Overprice]

Thanks for the quick reply. Have tryed the cleaning, no help. If it was also a cummins part I hoped I could get it cheeper.

Thanks

OVERPRICE

 

[Woodenhead]

Man this is an old post. Nice to see we're adding to an old post on the same subject instead of making another post.



I notice this was GClare only post since 2003, maybe I scared him away!

 

[DMoon]

The sensor is a halls effect unit and looks at a spot on the harmonic balancer to get a 1x pulse. The clearance between the sensor and the harmonic balancer is critical. Most likely cleaning the area where the probe looks at the balancer along with checking the clearance between the sensor and balancer will resolve the issue. As a rought adjustment use the width of a matchbook cover. Final adjustment values can be found in the Haynes or Dodge repair manual.

 

[Overprice]

I will try cleaning again. Would it hurt to use a emery cloth or do I need to stay with a contact spray?

 

[Dieseldemon]

Yes it is a Cummins part.