96 Chassis w/ 3 wire coils originally
MSLabs MS3 Basic
Had been running fine, all as expected prior to swapping to VVT w/ 01+ coils
Tacho output on in TS
Referencing: https://www.mslabs.gr/documentation/...7_v32_fw14.pdf

I had run what I thought was Yellow/Blue VVT output to the VVT solenoid for the new motor.
First start, notice no tach on dash.
Further inspection on the inside of the DB37 shows that what I had actually hooked up was pin 10, tacho output to the VVT solenoid
Further inspection of the DB37 shows that pin 36, documented as Yellow/Blue is visually Yellow/Black
I've since snipped the tacho output to the VVT solenoid, still no tach

Long story short: Is it possible to have damaged the tach driver, doing what I did? I'm actually a little surprised there's an additional tach output on the DB37 since it should have been going via the harness to the tach anyway, since 96 coils have no tach driver. If I likely didn't damage it, how the heck did I have tach on the dash functional before?

Thanks for any insight.

 

Yes, unfortunately you did damage it. The tacho on pin 10 on the DB37 is there so you can connect it to any accessories that need an RPM signal, such as W/I systems, shift lights, etc. Depending on what was actually damaged (the transistor or the trace on the board), you may be able to fix it by using one of the spare programmable outputs of the ECU: Just connect a spare output on pin 10, and switch the tacho output to the new output.

 

Thanks. Not happy, but good to confirm. Would the damage have been limited to the tach output then? Any reason for concern on the rest of the board?

 

Nothing else should be affected, contact me via email if you need further support on this issue.

 

Juuuuuust in case anyone wanted to see what happens when you do this :