Hi Michael,
There could be three probable reasons for this:
1) The Speedometer Cable is lacking in lubricant. This
causes the cable inside the sheath to get stuck
momentarily, get some torsional twist, then get enough
torque to break free. This causes oscillations to occur
where the speedometer would read in excess of a given
speed and lower then a given speed. This may also only
occur at certain speeds.
2) The white plastic insert in the front wheel is
slipping.
3) A combination of 1 & 2.
To fix the cable, I've seen people pour antifreeze down
the cable to lubricate it or replace it.
To fix the white plastic insert slipping, I've wrapped a
small amount of tape on it to wedge it tighter. Do this
at your own risk, as the counter argument to this is it
was designed to slip easily to prevent breakage elsewhere.
Paul
On 04/14/14 08:47 AM, MICHAEL W TOWNSLEY wrote:
I took my 83 Delorean out for a spin yesterday
after a long winter's hibernation. I drove about 6 or
7 miles at speeds around 35 to 45 MPH and the car
performed fine. When I accelerated to merge on to a 4
lane highway the speedometer started swing back and
forth wildly with 10 to 15 MPH variations. It seemed
to be more stable in second gear however at low speeds
it would drop to zero in 1st. In 3rd or 4th gear it
swing back and forth wildly. I thought I detected a
slight periodic noise coming the left front tire area
when accelerating after making a low speed turn. Has
anyone experienced this problem and been able to
successfully correct it? My Delorean has the Island
Turbo setup with a 160 speedometer I am not sure if
the after market speedo mod is the problem or not. I
have had the car for about 14 years and I have never
encountered this particular issue before.