Note: it is recommended to split thematically to several pages. (inputs, outputs, other wiring details, issues, etc...)
MembersPage/PerH/VemsWiring - detailed wiring is necessary to be able to help.
- (from the response last month, still neglected, apparently preventing effective help): no wiring details provided
- The method of debugging is to reproduce the setup (or parts of it) or review .vemscfg according to the detailed wiring.
- This is impossible if one or the other is not provided (or apparently neither, in this case).
- The method of debugging is to reproduce the setup (or parts of it) or review .vemscfg according to the detailed wiring.
- Important: Detail your wiring grounding. See GenBoard/Manual/GroundConnections
- Device will get damaged if grounding is not good.
Always examine the Validate ("check" icon) from Vemstune (after "update ini files from web"), that might draw attention to important issues or suspects.
Publish the uptodate (.vemscfg) config (and .vemslog if "dynamic" behaviour can be interesting) in case of any outstanding problem. That could allow tech crew or someone to reproduce your setup and perhaps find something that can help you.
See How to Report Bugs Effectively
2026-04-24
Introduction:
I have a '72 1300 GT Junior, and mounted a 2000 GTV race engine with 45 Dellortos. Now i'm in the process of installing FAJS ITBs and the following equipment:
Trigger: VR primary using standard 60-2 wheel from Alfa 75 TS and a custom sensor mount:
https://photos.app.goo.gl/N9hCkHMZMPPiGVMNA
HALL Secondary trigger using the distriutor (welded the centrifugal advance shut):
Other sensors are: TPS, IAT, CLT, Map (VEMS module), and one knock sensor (https://photos.app.goo.gl/GVaZPkz6Tbzyhf47A).
The VEMS 3.3 was ordered (by a friend of mine, who didn't use it) like this:
https://photos.app.goo.gl/WZB3iErdmVmpauTG6
Ignition is a standard Bosch ignition module running a motorcraft coil (wasted spark).
This is my wiring list (note the multiple sheets for compartments).
__________
With everything connected, I verified that all sensors except primary trigger was functional.
Problem 1 (VR Trigger): SOLVED (solved by "lifting" p259 VCC and soldering it back and now works?)
VR Sensor was dead.
- If "VR sensor is dead, replace VR sensor". You mean VR input is dead? What is the measured resistance of VR sensor?
Tested one i know works from another car in addition to the brand new one for this car, and the sensors were also verified to the EC36 connector using oscilloscope.
I also connected the VR sensor only i this test setup:
https://photos.app.goo.gl/bzDayVM8pNMGwoHA9
No luck, not one single trigger event in the log. Dead p259?
Reply from support:
- If you disassemble the device (remove endplate first, unclamp the 2 or 3 clamping plates before removing frontplate screws; Be patient, don't damage the insulator-sheet)
- you can measure the +5V supply of p259 (and LM1815) chips. The related regulator also might get warm, indicating current * voltage = dissipated power
- See GenBoard/VerThree/Schematic
- If the LM1815 VCC is less than 0.8V (eg. the actually measured 0.4V indicating that likely damaged p259 is shorting it), removing p259 might be a good idea.
- Make a rectangular window from aluminium foil to prevent neighbor components from falling off when heating the p259 chip with hot-air heat-gun
- But first review and fix and document your GenBoard/Manual/GroundConnections
Reply from Per:
Thanks, Will update with findings. I verified ground setup with a DVM earlier, but i'll check with a precision milliohm meter as well.
Measured the new VR sensor to 815ohms, and a older functional one to 650 ohms. Both make voltage when you put metal in front of it.
Update from Per:
Measured 0.4V on P259 VCC - Soldered off P259 VCC - Measured 5V on LM1815 VCC - Soldered P259 VCC back on - Trigger is working!
Maybe i found a short around the pin i took off?
- Could P259 latch GND to VCC and stay there? Thus me resetting it by taking off VCC pin?
- not sure what happened, unusual indeed
- Ground system verified and OK.
Problem 2 (Relay outputs):
I have the VEMS ignition, fuel pump and coolant fan setup with 9 fuses. fuel pump relay ground is connected to EC36/17 (injector channel) and Coolant fan at EC36/6 (injector channel).
None of these relays actuate in test mode.
Reply from support:
- You can configure for MISC1 or MISC2 output, and change the inverted flag (in outputs dialog) back and forth to test.
- (note: use a "diagonal matrix in injector output groups dialog, so each group contains exactly one injector FET output).
- If there are damaged injector channels, removing or replacing the p259 will NOT fix the problem.
- See [repair/upgrade] if you cannot or do not want to fix it yourself.
- VemsTune: See [vt] Even with newest VT, for new (round or ECU) firmware compatibility, please: Preferences / Update ini files from web. - confirm that you've done Update ini files from web.
Reply from Per:
I did check that the actual injectors worked, and they did. I used the other outputs dialog to test fuel pump and coolant fan, where I assigned the channels and had a test button?
The ini files and firmware are up to date, i can post the versions later.
Update from Per:
VemsTune 1.5.57 - FW 1.2.38 - "no new ini files found" when updating from the web. Still havent found the issue here.
Re-checked that Pin 6/17 is connected to relays ground pin, but does not actuate relays. Suggestions to other more suited channels?
Problem 3 (ignition outputs?): SOLVED
I haven't tested much on this yet, but i was unable to get plug spark using test mode. Will look more at this and update.
Reply from support:
- always make sure to have GND return path. But with other problems, it is recommended NOT to try to spark. Use 1k resistor in series with a LED, and test output with that (the anode to +5V, testing 1 switched output at a time).
Reply from Per:
I found a passage about enabling the stepper driver in the user guide - setting water pump channel to S259/7 and start temperature to -40? (or using a misc output to activate S259/7 unconditionally). Maybe that was what was missing?
Update from Per:
That was it - setting up water pump channel did the trick, enabling the stepper driver unconditionally by activating S259/7 I now have sparks!