Digital dash issue - failure #2

Ouch! Another dash failure. This time I hadn't driven the car for but an hour when it went all dark on me. No errors or anything this time. It just went dark while driving. I described the symptoms to diyautotune.com and they had me open the display and take photos of the LEDs. At the time they said it appeared to be a power supply issue so another RMA was created. I tore down the instrument panel and pulled the center console for the umpteenth time, boxed up the digital dash and shipped it back to them. Their findings:

Findings: Blown transistor identified

Resolution: Replaced the damaged transistor and added a built-in fail-safe to help this from happening again the future. The issue was likely caused by a voltage spike. We also recommend inspecting the vehicle's electrical system to identify and correct the source of the voltage spike before installing the ECU. Unit passed a full QA test after repair.

Voltage spike... hmmm. This time I am not taking any chance so here is the game plan:

The clock plug was a very convenient source for the power inputs but the wiring may be undersized and the clock plug itself may not be making good contact. Instead, pull the power from separately fused circuits and add two separate voltage regulators that provide a constant 12V output:

• +12V always on: Pull from Cigar Lighter (converted to HDMI port) circuit; fuse XX. Add voltage regulator #1
• +12V ignition on: Pull from XXX circuit; fuse YY. Add voltage regulator #2
• +12V lights on: Pull from XXX circuit; fuse YY.
• Improved ground

The two voltage regulators fit perfectly inside the left driver's side knee pad:

Voltage regulators

I am also redoing the terminal strips. The ones I have used until now are not the best of quality and the way they are installed have the input/output wiring awfully close to a metal bracket that is grounded so there is a potential for shorts. Instead I will install a higher quality terminal strip onto a wooden strip further up on the fiberglass, away from the metal. 

Digital dash issues - failure #1

Do I have electrical issues? I was never too sure but fact is that the dash would drop out for a second or two every now and then was certainly an indication of that. So one day when I was out driving the dash went dark on me. It wasn't until I turned off the ignition and then back on it would display the "No Signal", and when I turned the ignition OFF the display would come alive with this error message:

After the message had been cleared the screen would switch to the boot-up screen and then it powered down. After some emailing with diyautotune.com they had me ship them the display on an RMA. Turns out it had a blown capacitor; they also replaced the main board. They mentioned the following as possible root cause(s):   

• Overheating - can cause transistor failure
• Over-voltage or voltage spikes – surge from the ignition system, alternator, or wiring issues
• Improper grounding or wiring faults - poor grounds or wiring issues

The fact that the dash has a fan (moves very little air, but still) coupled with the fact that the binnacle encloses - almost hermetically seals - the digital dash when installed lead me to suspect overheating. I purchased this blower and wired it to +12V ignition on . Turns out the blower fits perfectly inside the right driver's side knee pad:

Blower installed in the right knee pad

I sealed all holes behind the instrument panel except some openings on the far end to make sure the blower moves air across the back of the display and then out, under the dash. I am very happy with my solution. And no worries, the blower outlet is located inside the binnacle and is not showing when the binnacle is installed.

Belt tensioner

The belt tensioner had started an occasional squeal and chirp. I found a perfect drop-in replacement on Amazon for about 90% less than the equivalent VW part. Perfect fit, perfect quality. The VW model number was even cast into the housing - the audacity... Oh how the Chinese have mastered the art of reverse engineering on a dime...

Old tensioner on top, replacement at the bottom

Digital dash (finally)

It's been nine years since I started talking about it but it's finally happening. I have purchased the digital dash extension of the MS3 Pro, referred to as DD-EFI. I opted to the 12.3" Pro Dash model. It comes with with all the analog and digital inputs you need to display all parameters you would expect. The display is touchscreen but I purchased the wireless keyboard regardless.
Here is the stock instrument panel before I started taking things apart:

(Note the disjointed plastic surround at the top that I have never been able to get to seat properly since I had the binnacle recovered. Good thing that will be gone.) 

I made a mock-up of the display including the computer to doublecheck that the stock binnacle can be used:

Looking at it from the front. I have a custom, extra-wide bezel on order to fill the entire width of the binnacle. Set me back $50. A steal:

Work is underway:

   

There are basically five separate connectors on the DD-EFI dash: Power, CAN-Bus, USB cable (b/w ECU and dash), Digital In, and the Analog In. There is also a GPS for speedometer and odometer but at this point I think I can trigger the speed input signal from the Crank Shaft Position sensor so the somewhat less accurate GPS is my backup for now. 

For the power you need:

12V always on
12V switched
12V optional switched (for triggering dome lights, door switch etc)
12V dimmed
Ground

I was pleased to find that the plug for the digital clock in the console holds all the above power parameters (check on 12V dimmed) so I made a harness for the clock's power plug. The clock didn't work regardless so I will be more than happy to retire it (for the moment).

(pic of power plug)

Binnacle re-recovered including custom sized Bezel

Here is what the re-recovered binnacle from Shawn Cook Auto & Trim in Murphy, TX looks like. He did a good job smoothing out the sides of the binnacle and also creating a distinct step for the bezel to mount against from the back. He matched the vinyl and stitching from before to make sure it it matches the rest of the interior. 

For the CAN-bus I traced the two wires from the ECU and soldered in an extension between it and the dash. The 6 ft USB cable turned out to be short so a longer, 10 ft d:o, was procured.

Digital In: The following discrete inputs were chosen: (may change)

DI1: Left turn signal            DI5: Oil light

DI2: Right turn signal          DI6: Low fuel  

DI3: High beam                   DI7: Door ajar

DI4: Low beam

Analog In: This is where the confusion started. The so called Pro Dash Complete Manual is indeed detailed and is (almost) accurate (several screenshots with software selections that did not exist in my Tunerstudio) but to my astonishment it only covers the input/output aspects and the settings for such. It completely leaves out how to create a dashboard and how to build your gauges and how to make your input selections. It may sound intuitive but there is myriad of selections that if not completely correct, the gauge wouldn't read right. Also, you need to be clear on which inputs come from the ECU and which ones come from the external sensors, and there is no common sense delineation between the two. I did come across a list of the ECU parameters and once I learned that, then I realized why a given input that resides in the ECU could not be read from the vehicle sensors, and vice versa. An example: I tried to make Battery Voltage as one of the analog inputs to the Digital Dash but the analog in selections only consisted of pressure, temperature and travel - so what about voltage? Once I learned that voltage comes from the ECU then I had a working battery voltage gauge in minutes, and so on. So for posterity, here are the ECU parameters (need to find where I found them):

RPM                                           Boost                                        Voltage

Coolant temp                              Target Air/Fuel Ratio (AFR)    Spark timing

Manifold Air Pressure (MAP)    Actual AFR                              Miles per gallon  

Manifold Air Temp (MAT)        Closed Loop Idle                      Shift light

And here are the Analog In inputs that were chosen:

AI1: tbd                  AI5: Oil temp

AI2: tbd                  AI6: Oil pressure (pre-config)  

ADI3: tbd               AI7: Fuel level (pre-config)

ADI4: tbd

A pic of your truly, working away during the coldest couple of nights of the year, trying to get it ready for the upcoming North Texas Irish Festival: 

Feb 18, 2025. Quite possibly the coldest evening I had ever experienced in Texas. But, hey, gotta carry on... 

The void inside the bezel/behind the digital dash computer was used to house the terminal strips. In this picture you can see three terminal strips:

The two top ones mimic the vehicle's stock instrumentation the way the connected to the stock instrument panel with connection points A1-A16 (ref. Delorean wiring diagram) at the top and B7-B12 below that. The bottom one connects the outputs from the Breakout Board (further down) to the digital dash. I also put heat shrink wire labels for easy identification.

Terminal strips

Terminal strips as seen thru the windshield

work in progress

Another thing I learned was that my stock Delorean oil pressure sensor would not work. It is of the one-wire type so I think it is simply a circuit with a variable resistor. Not that it was explained explicitly in the manual but before long I realized why DIYAutotune sell sensors too, as the Digital Dash is designed for a 0 - 4.5V input signal and those are the types of sensors DIY Autotune offer. I opted for the combo oil pressure/oil temperature sensor by Low Doller Motorsports. It had an 1/8" NPT, just like the stock sensor, and was easily replaced. The cable was routed into the cabin via the (electrical cover) and was just long enough to reach the little cubby under the shelf where the ECU goes. Here I mounted the Breakout Board where I terminated the oil pressure/temperature sensor wires. I also pulled the Fuel level input wire to the breakout board, and from there I connected the three signals to the digital dash up front. That part worked out really well.

open breakout board to the left; cover installed to the right (below ECU)

Once I understood the delineation between data from the ECU and vehicle sensors, another quirk in the manual was it showed that you needed to make that selection (MS-ECU vs DD-EFI) up front. I searched high and low for that selection only to find that, in my software version, it has been changed to a local setting within the parameters you are working on. It may sound simple now but caused unnecessary confusion nevertheless.

Another minor curveball was that the screws that attached the display to the bezel had become too short. Reason being that the upholsterer had wrapped the vinyl around the back of the bezel (as I had expected him to) which resulted in the display being separated by 3-4 mm from the bezel. The solution was M2.5 x 12 mm screws specifically for plastic, from McMaster-Carr. Perfect.

Original (black) screws being replaced with longer (stainless) screws

The dash could now be test fitted in the binnacle:

The entire binnacle assembly installed very nicely in place. There was plenty of space to tuck in the terminal strips and excess wiring.

To facilitate binnacle removal in the future I decided to only use the two rear-most M5 studs to secure the binnacle and to my amazement it held perfectly in place. Instead of the two regular nuts I ordered some 20 mm long nuts - reaching up above the steering column and around the A/C duct is a pain, so the tall nuts will surely help. Another thing I added was a pair of USB extension cables for two of the dash computer's USB ports; basically a 18" cord with male/female ends that extend down under the dash which provides easy access to the little dongle for the wireless mouse as well as inserting a thumb drive.   

Another pic of the almost completed job... only seat and steering wheel left:

I decided to calibrate the the fuel sender by pulling the fuel pump assembly and match the resistance values to the float level:

Fuel pump and float

I ended up at the following two Empty/Full values:

I am finally to a point where EVERYTHING is working. Even the odometer is incrementing like it should so for now here is the final result (for now):

The two icons at the top are Intercooler On and AC Compressor On indicators. Zooming out:

Note the two blue USB extensions at the bottom. One is for the mouse dongle and one is for a USB stick, if you need to upload/download files to the dash. Also note the GPS antenna at the top left on the dashboard.

Improved throttle bracket

 A source of irritation has been that the throttle tends to be s little sticky when you were giving it just a little gas, just off-throttle, so I  decided to do something about it. The issue was that the angle at which the throttle cable lines up with the throttle body was really awkward and caused the stickiness. My solution was a piece of stout 1 x 1/4" aluminum bar stock and a simple pulley that lines everything up.

Throttle cable with pulley (no worries - the cable was not cinched up yet)

Eventually I would like to build a drive-be-wire system to get rid of the old school throttle cable. Looks like the DBWX2 might be a viable option.

Slow starter issue - FIXED!

It’s been a long time coming but I have finally resolved my slow starter issue. Back in 2018 I upsized the positive cable; I also replaced the starter but none of those were really the problem. The real problem was a poor ground.

To address the poor ground I purchased:

• 25 ft of 1/0 AWG Pure Copper Power Ground Wire Cable
• a handful of 1/0 AWG 3/8" Stud Copper Wire Lugs
• a set of crimping tools
• and some dielectric grease

Then I ran one cable from the battery to the transmission:

Grounding point at transmission

... and another cable from the same point on the transmission to the original grounding point i.e. to the reinforcement plate of the right rear trailing arm:

Grounding point at trailing arm

I also ran an additional cable from the same point on the transmission (left cable in the pic below)...:

Added ground cable running to the front (left cable)

... to the common grounding point for all accessories in the front, including the headlights:

Front grounding point

A word of caution, getting the trailing arm bolt back in took a ton of McGuyverism as the alignment of the plate and bushing etc. had shifted ever so slightly and it was a bear to avoid cross-threading the bolt as I was trying to getting it back in. The solution was to get a 5 mm longer bolt than the original (same spec) and grind the first 5 mm to a point so it would align itself. (An even longer bolt with a more pointed tip would have helped but that would have caused it not to screw all the way in as it would interfere with the frame on the backside.) So, the pointed bolt and all kinds of clamps and jacks to help lining things up got the job done. Oh yeah, add the minimal ground clearance with everything just a couple of inches from your face just added to the challenge. In hindsight, I do not see this point as a good grounding point anyway. A better option would have been to modify the ring terminal into a spade terminal and that way only having to loosen the bolt a bit – not pull it out completely.

 So – with all that in place the car cranks like crazy:

And the voltage gauge is showing a healthy 13+ V!

Looking forward to enjoying the (hopefully) brighter head lights at my next evening drive!

New variable displacement A/C compressor

My D uses a variable displacement air-conditioning compressor - a Sanden SD7V16 model #1216 to be exact (yes, Dan!) - which is as the name would indicate a compressor that varies its displacement automatically based on the prevailing conditions, without clutch cycling. Given that I am running a turbo setup, i.e. low torque at idle, the clutch cycling of a fixed displacement compressor would stall the engine at idle so a variable displacement is a MUST.
The heart of the variable displacement feature is the so called Mass Flow Compensation Valve (MFCV), but if it starts to act up the compressor will stop modulating which is what appears to have happened with my compressor - it was stuck in minimum displacement so it was time for a new one. 

Old and new compressor

Old compressor removed

New compressor

I got about 75 cc of clean (no sign of any trash in the system) but darkish looking oil out of the old compressor and after having drained the replacement compressor I added about 100 cc of PAG 46 (equivalent to Sanden SP-10 oil) to it before installing it. The system pulled a good vacuum and after re-charge it was spitting ice cubes again!