VVTi Control with AEM EMS-4 Question(s)

[KTS]

I recently installed an AEM EMS-4 Standalone ECU into my JDM Vitz RS with a 1NZFE manual transmission.

I have the AEM EMS-4 wired parallel to the car's ecm.
The EMS-4 is being used to control fuel and ignition. The injector and coil wires are cut off to the car's ecu. All OEM sensors that the aem would like to see (i.e coolant, knock, cam, crank, throttle) are spliced into the EMS.
I removed the stock O2 sensor and replaced it with an AEM EUGO kit.
I also installed a map sensor and an Intake air temp sensor as the MAF sensor is going to be removed eventually but is still currently connected.

While on the dyno there was no difference to the power/torque curves with the OCV (which I assume is the solenoid that controls the VVTi) either connected or disconnected.
The EMS-4 is able to control VVTi. The OCV has two wires; ground and 12V. the ground wire was cut and is connected to the EMS-4 (GPIO connection) while the 12V wire remains. This also has no effect.

When the 12V wire is cut and then connected to the battery the engine has a lot of detonation/knock.

The OCV was removed and tested as described in the vehicle's manual.

Has anyone had success tuning the VVTi using AEM S1, S2 or EMS-4 products and would like to share any info as to how they had success.

A friend of mine how is a very respected tuner is responsible for the tuning.

[CTScott]

The ECM directly connects to both terminals of the OCV controlling both the power and ground. The ground side is just that and the power side is pulsed with a duty cycle relative to how much the valve should allow oil to flow through to advance or retard the timing.

You should never just connect the valve to +12 and ground, as you will burn it out doing so.

For the EMS to control it properly and make it have any effect on how the car runs you have to have the output be a pulsed output where you can set the duty cycle (as opposed to just switching it on or off at certain RPMs). I have not used and EMS with a Toyota engine with VVTI, but have used an Adaptronic stand-alone with a 2ZZGE and adjusted both the VVTI and VVTI-L (as that engine is a dual cam Toyota engine).

[Jason@SportsCar]

We have successfully controlled the VVTI with both a CamCon unit and my current AEM EMS 2. No idea how it is wired or the unit is programmed - I know my limitations and pay professionals for stuff like that - but it can be done.

[KTS]

Thanks guys. I'll find out exactly what info the tuner needs.

[Bluevitz-rs]

It might be advantageous to monitor a stock OCV for Hz (duty cycle) in normal operation to get a starting point on what values to set.

CT, you mentioned the ECM controls both ground and 12V wires. Does the valve work in two directions. Positive polarity for advance and negative for retard, or something to that effect?

[CTScott]

It might be advantageous to monitor a stock OCV for Hz (duty cycle) in normal operation to get a starting point on what values to set.

CT, you mentioned the ECM controls both ground and 12V wires. Does the valve work in two directions. Positive polarity for advance and negative for retard, or something to that effect?

No. It actually does it all via pulsing the positive terminal. It is constantly being adjusted though, so less or more flow through it allows retarding or advancing the timing.

[KTS]

Good info as always CTScott.
Jason@SportsCar are you able to share some setup info or provide either a screenshot of the VVC setup tab for the series2 or a base map with the VVTi working?

[KTS]

Are there going to be substantial gains from having the AEM EMS-4 controlling VVTi?

[CTScott]

Are there going to be substantial gains from having the AEM EMS-4 controlling VVTi?

Not really, but there will definitely be losses if the valve is left in a fixed position.