2.3L ('83-'97) Speedo bounces.

[corerftech]

Had to pull trans and I had never seen the truck ambulatory prior.
I have had the cluster out for service, the sending unit on trans out as well. (Manual trans).
It was missing the cable retention clip, I replaced with JY part, just the clip.
Cable snaps in solid.

Speedo bounces, advances as it should but bobbles like a chicken head.

Where do I look for a cause?
Prior I thought the clip missing might be it but nope.
I did get a full sending unit from JY, I find nothing wrong with the existing gear and device though.

I also have a complete cluster with a known good Speedo that could be swapped——- the ODO doesn’t match vehicle miles anyway—— but I really don’t want to.

Thoughts?

Minutia——- sucks!

 

[RonD]

Usually its a broken wire on the speedo cable

Speedo cable is a stranded wire/cable, if a wire breaks then it hangs up on the sheath causing the bounce of the needle

And yes, it can be the speedo itself

Inspect the speedo cable sheath for external damage, you can pull out the cable itself for inspection, lube and put it back in

Years ago they used to sell Speedometer cable core kits, because this was a common issue, looks like they still do

 

[rusty ol ranger]

What year is the truck? If its new enough to have an electric speedo then its probably a ring issue inside the rear diff

 

[corerftech]

Mech Speedo, 1990

 

[rusty ol ranger]

Mech Speedo, 1990

Ok...then what ron said lol

 

[corerftech]

I procure from the local shop a quality Speedo cable (complete). About a week later installed it.

speedo end is correct, trans end is very different, larger diameter spud, different locking system.
Pissed—- already had it in the car and in the dash——- I verified it resolved the problem (damaged outer sheath on old one causing bouncing and very stiff rotation of inner cable) and measured the spud for the speed sensor drive.
The OEM cable has a steel formed tip with a collar that snaps into a spring clip retainer on the sensor, the spud is about .390 inch. The new one has substantially longer drive cable tip (a good thing) and is .440 diameter. It clearly can’t be installed in the speed sensor. Later is lathe turned and solid as opposed to oem, thin wall formed tubing.

In a bind- I got the F-it’s.

I am a machinist, certified, ( but no good for engines!) and figured aside from the oil o-ring inside being undersized, there was no reason I shouldn’t open the to .440 (close fit) and attempt to retrofit the new cable.
I had a .440 bit, opened and it was an interference fit. I was able to install the o-ring back on the seat inside, bent the retainer clip a bit different and use about 19 hands to get the spud installed (snapped in and TIGHTLY Sealed).

the Speedo cable is one with the sensor, zero play or slop in any direction.
Speedo works too.
Thanks again RonD for another direct hit.

 

[RonD]

Good work, good machining, lol

Thanks for the update and THE FIX