Does anyone know what the frequency of the PWM signal from the PCM to the turbo wastegate solenoid is?

When I looked at it with my scope it looked like about 33Hz, but I was expecting it to be higher than that.

Why were you expecting that?

I just figured it would be higher than that. Do you know if the 33Hz (approximately) I measured sounds correct?

Thanks.

That is correct, as is the 4L80E TCC PWM signal - they are PWM, not PTM, or frequency variable - the low freq prevents EFI modulation betwixt the alt and FSD -

- they are PWM, not PTM, or frequency variable - Yep, that much I knew, I just did not know the frequency.

I converted my 96 from a DS4 to DB2 last year and have not yet gotten around to enabling the wastegate. I was planning to go to a mechanical wastegate actuator, but recently I figured I could make a simple PWM controller to operate the existing vacuum actuator. I just wanted to get an idea what frequency the factory operated the wastegate solenoid so I would have an idea where to start.

Thanks for the info.

Cool - adjustable Boost from the driver's seat............

exactly! Plus I can take advantage of the existing actuator. If I can't get it to work I can always switch to a mechanical actuator.

Can also get a surplus miniature mechanical adjustable vacuum regulator, install it in the cab - looks just like a pressure regulator, but for vacuum

I can't see adding a PWM controller being a problem but I was wondering about defueling or DTCs by over boosting without an ECM reflash. Guess it would work similar to the mechanical spring setup but I thought those needed a chip or reflash as well.


I think you can look up the specs of that solenoid online. What is your plan to control boost at different rpm and engine loads?