Forum » EFI Wiring Fundamentals » confused with H-bridge wiring

confused with H-bridge wiring

EFI Wiring Fundamentals

Discussion and questions related to the course EFI Wiring Fundamentals

Page 1

Hi i have a ECU master black.

i am looking to connect VVTI and variable valve lift and DBW to H-bridge pins on the ECU

the ecu provides 4 pins for this.

H-bridge#1 winding A

H-bridge #1 winding B

H-bridge#2 winding A

H-bridge #2 winding B

am i right in saying . ie DBW. needs to have a winding a and winding b wired to it to rotate the motor open and back to closed progressively ?, VVT would also be the same ?

Then there is no pins left for the variable valve lift , but this isnt progressive like the other 2 solenoids so can i connect the variable valve lift to an AUX output to control this?

i might have got this wrong, any information is appreciated

thanks scott

If you are replacing a stock ECU, how was it wired?

Hi david,

Yes its to replace the oem ecu. For the throttle . It runs a cable for the TB originally but i am changing it to a bigger TB and DBW.

As for the vvt and variable valve lift on how there controled through H bridge or not on the OEM ECU i am not sure sorry. Best to find out how there controlled? On OEM ECU?

It's always best to understand how the stock ECU controls the various outputs. For example, you can measure the frequency and duty cycle of the signal going to the VVT oil valve, using an oscilloscope. You will need that info to setup your Standalone ECU.

I suspect the 'winding A/B' part of the pin description is to do with using the h-bridge outputs to drive a stepper motor, which is not what you'll be doing. As your DBW throttle will be a DC motor it'll only have two wires. One is connected to 'H-Bridge #1 Winding A', the other to 'H-Bridge #1 Winding B'.

Think of an H-Bridge as a pair of outputs, when one is providing power, the other is providing ground. The key part of them though is that each output can be either a power supply, or a ground, but its paired pin will always be the opposite. This is what lets you control the DC motor in the throttle in both directions.

Depending on the cam control solenoids in question, they're often best thought of like a DC motor too, except that instead of rotating, they move a spool valve internally against a spring. The spring give the valve a default position, and you drive the valve either way against the force of that spring.