Second set of eyes on a wiring diagram/plan

[djhedges]

I recently purchased a Link Fury X and Razor PDM for a small winter project.  I'm rewiring a 93 VW Corrado race car.  This will be my first time wiring a car and I think I might have most of the wiring planned out.  I would appreciate if someone could take a second look and see if anything looks wrong.

The image below is the wiring between the ECU and a Deutsch connector I'm planning to use to make pulling the engine easier.  As an example the crank position sensor will use pins 7, 10 & 11 on the Deutsch connector which correspond with +5v, Trig2 & Shield/Gnd on the Loom A connector.

Theres also invidual graphs per node such as the various sensors and connectors if the image below is too busy in some areas.

https://github.com/djhedges/corrado_wiring

As an example.

 

[Adamw]

Thats pretty hard to read, and it is going to make it pretty tough when it comes to building the harness.  Have you ever used "Scheme-it"?, I would typically start with something like that, then do like a point to point connection list in excel or similar and a layout with some type or drawing software.  

I only had a quick look over the engine bit.  A couple of things that looked out of place:

"Coolant low sensor" is connected to aux 4?

The two oil pressure switches are connected to AN Volt inputs, thats not going to work since they dont output any voltage.  Connect to digital inputs.  

[djhedges]

Thanks for looking. 

I wasn't sure what to connect the two pin low coolant sensor from the VW coolant reservoir.  If I recall correctly this is simply two pins submerged in the coolant.  If coolant is present it closes the circuit.

I have not seen Scheme-It yet.  It's not the prettiest diagrams but I guess I've gotten used to looking at them.  I found using graphviz the easiest to maintain so far.  It's defined once in https://github.com/djhedges/corrado_wiring/blob/main/corrado_wiring.py by defining nodes and paths.  For example.

Node('icm', ['Transistor1ecu', 'Transistor2ecu', 'Transistor3ecu',
             'Transistor3coil', 'Gnd', 'Transistor2coil', 'Transistor1coil'])
Node('coil', ['Coil3', 'Coil2', 'Coil1', 'Ubatt'])

# Coils
AddPath((
  ('razor_pdm', 'PWROUT3a'),
  ('coil', 'Ubatt'),
), 'red')
AddPath((
  ('icm', 'Gnd'),
  ('engine_bay_ground', 'Gnd'),
), 'black')
for i in range(1, 4):
  AddPathWithMap((
    ('link_ecu_a', f'Ign{i}'),
    ('icm', f'Transistor{i}ecu'),
  ))
  AddPath((
    ('icm', f'Transistor{i}coil'),
    ('coil', f'Coil{i}'),
  ), 'white')

[aerace_fab]

You should highly consider using excel or google sheets to make this diagram. 

If you need help i can show you a few examples of how it's done properly.

[Admiral Akhtar]

I'd personally advise binning off the VW Coolant reservoir level sensor, if it's not absolutely critical to your build.
They're known to commonly fail and in some case draw coolant back up the plug, into the loom and through the wiring to the ECU 

[djhedges]

Now that you mention I seem to recall the coolant reservoirs wicking being a possible issue.  I'm torn though because having that signal could save an engine.  I'd rather redo a harness then have the engine rebuilt.  On the plus side race cars get wrenched on so much that hopefully I'll catch it early on.

On 1/3/2023 at 4:43 PM, aerace_fab said:

You should highly consider using excel or google sheets to make this diagram. 

If you need help i can show you a few examples of how it's done properly.

I'd be happy to take a look at a google sheet example if you have one handy.  I could always export what have to now to sheets if needed.

[Admiral Akhtar]

21 hours ago, djhedges said:

Now that you mention I seem to recall the coolant reservoirs wicking being a possible issue.  I'm torn though because having that signal could save an engine.  I'd rather redo a harness then have the engine rebuilt.  On the plus side race cars get wrenched on so much that hopefully I'll catch it early on.

I'd be happy to take a look at a google sheet example if you have one handy.  I could always export what have to now to sheets if needed.

If you're rapidly losing coolant to the point the sensor is your warning, the engine has likely already blown a headgasket or pipe and will be venting steam 
You're better off monitoring coolant temps for irregularities or coolant pressure for sudden spikes when the level fluctuates