Took car to the beach over the weekend, and on way there car started to act weird, shuddering like it was going on and out of torque converter lockup, pulled over and while sitting still, ( engine still running and in drive) speedo was bouncing all over over the place. Shut car down and just did a quick walk around check and everything seemed fine, fires it back up and put in drive, speedo steady at 0, drove rest of the way without incident! Drove home this morning without incident! Wondering if the speedo bouncing and the shudder are connected or not, i am using the Dakota digital 5e or something along this lines to convert the pcm signal for the jag speedo, anyone else using it? And get bouncing ( only while sitting still in drive) I will be scanning car tonight and making a data log to see if the vss is causing the bouncing or if it’s unrelated, vss will cause lockup issues etc, hoping I’m on the right track here, more to follow

 

My car uses that Dakota product. Several sip switches on ot to get the correct match. Caveat. I did not get the connection right!!!! used a VSS signal, rather than a speedo signal from the PCM. I have stuff to fix it. Not likely nowadays,. I just live with speedo 49 real speed 25!!

To the point. A call to the Dakota tech guy was most helpful. Good folks.

 

Darren,
Since mine hasn't been on the road yet, I don't know how much I can help.

I am using the Dakota SGI-100BT interface. It will coordinate both the tach and speedo. I hooked it up and did a "parked" test over a year ago. I am leaving the PCM harness "stock", so the VSS signal is going to the PCM as normal and I connected the PCM/SPD output to the input of the SGI. I hooked up OUTPUT 1 (there are 5) to the Jag speedo after choosing an output frequency from the SGI (there are 5 of them too) and the speedo read very close right off the bat. The SGI can be fine tuned once you're on the road with the onboard digital display.

I don't know how the 5e unit you have compares to mine, so all of this may mean nothing. Because I am letting the PCM control everything on the engine and transmission as normal, the SGI is only connected to the PCM outputs of speedo and tach, nothing to do with the transmission.

If the converter was locking/unlocking when it shouldn't be and the speedo was bouncing around, those are both electrical issues of some sort. Are you using the PCM speed output as your "5e" input? Again, I don't know how that one works. From Carl's comments, it seems using the PCM output instead of the VSS output is the better deal. You might check the connection/wiring of the TPS and MAP, they should both play a part in when the converter/trans shift. Did you wire a converter disconnect switch on the brake pedal? Something there might have come loose.
Here's a picture of my SGI.

My time is coming.

Dave

 

Dave, everything is controlled via pcm, I am tied to the pcm output for speedo not directly to vss, the adapter I have looks very similar to yours, but only does speedo, you have to set ppm etc , i did not notice us speedo was acting up when car was, so all this may be for naught,
I had no stored codes, and I did a data log run today and of course car was flawless, everything checks out perfect, I supposed it could be a bad ground on the adapter causing the erratic behavior ) that I only saw sitting still) or something like that, sputtering could have a been a piece of trash in fuel line or God knows what… for now i will
Continue to drive it and keep laptop in car to scan as soon is it( if it) happens again

 

Good luck, let us know what you end up with.

Dave