Haltech VVTL-i setup help

[Extratx]

Hi Guys. I have a mid engined 2ZZ-GE powered race car that has a Haltech E8 ECU in it. I am working on it for a friend who got the mega shaft from the original install shop as they went out of business half way through the project. I am having a little bit of trouble getting the VVTL-i working properly, and i need a touch of info on exactly how it works. I apologize I am not a Toyota engine expert by any means, however I am very experienced in fuel injection, engines, etc.

The engine has two solenoids for the cams, one on the cam belt (front) of the engine and one on the flywheel side of the engine. The cam position (home) sensor is on the flywheel side of the motor on the intake cam. It is a 4 -1 sensor, aka 4 positions 90 degrees apart, with only 3 of 4 teeth.

Best I can tell the solenoid on the front of the engine controls the advance of the cam, and the solenoid on the flywheel side controls the lift.

The problem we are having is that once the engine hits 5100 rpm, the cam advances over 45 degrees, confusing the haltech ecu as to where TDC is. We can set the Haltech to advance the cam at a lower RPM, but the cam advances at 5100 rpm even if the solenoid is not activated.

The lift solenoid changes the pitch of the motor, but is not having an effect on this problem.

The end result here is that the engine cuts out at 5100 rpm and does not come back on until it falls to about 2000 rpm.

Anyone have knowledge of what is happening here? Should the cam advance by itself? I have a video of the oscilloscope showing the crank trigger, the cam position, the injector pulse, and the ignition. It shows the cam signal jump right when the motor cuts out. I will try and find a way to post the video here.

Thank You,

Jon

[Extratx]

After digging for more info, I have found that the cam advance is PWM (pulse width modulator) controlled and constantly variable, where the lift solenoid is on-off ala vtec.

Does anyone have the frequency vs. RPM chart for the stock cam advance?

The Haltech has a way to account for the movement of the cam and hence cam position signal given RPM, apparently i just need to get the data right.

Thanks.

[Tang0_au]

i run my vvt output at 120 hz

[Extratx]

I guess this setting is only for the fixed frequency of the pulse, doesnt change frequency to move the cam? Do you know how the ECU keeps the cam where it wants it? If it isn't with frequency then is it with voltage? Do you know the signal required to keep the cam at the fully retarded and fully advanced position?

I know without any control, the cam will move by itself from retarded to advanced around 5000 rpm.

There is info in the data logging portion of the ecu for Current cam position and desired cam position. We will use these for making sure the cam is behaving.

Thank you for the info Tang0_au, we will be working with the car more today.

Cheers

[turbophil]

Have you checked your Cam PIDs and adjusted them? The solenoids will work (using a loose interpretation of the word work) at many different frequencies. but the PIDs will dictate how closely your cams follow the setpoints...

Good luck,

Phil

[Kris from DRS]

Originally Posted by Extratx

Hi Guys. I have a mid engined 2ZZ-GE powered race car that has a Haltech E8 ECU in it. I am working on it for a friend who got the mega shaft from the original install shop as they went out of business half way through the project. I am having a little bit of trouble getting the VVTL-i working properly, and i need a touch of info on exactly how it works. I apologize I am not a Toyota engine expert by any means, however I am very experienced in fuel injection, engines, etc.

The engine has two solenoids for the cams, one on the cam belt (front) of the engine and one on the flywheel side of the engine. The cam position (home) sensor is on the flywheel side of the motor on the intake cam. It is a 4 -1 sensor, aka 4 positions 90 degrees apart, with only 3 of 4 teeth.

Best I can tell the solenoid on the front of the engine controls the advance of the cam, and the solenoid on the flywheel side controls the lift.

The problem we are having is that once the engine hits 5100 rpm, the cam advances over 45 degrees, confusing the haltech ecu as to where TDC is. We can set the Haltech to advance the cam at a lower RPM, but the cam advances at 5100 rpm even if the solenoid is not activated.

The lift solenoid changes the pitch of the motor, but is not having an effect on this problem.

The end result here is that the engine cuts out at 5100 rpm and does not come back on until it falls to about 2000 rpm.

Anyone have knowledge of what is happening here? Should the cam advance by itself? I have a video of the oscilloscope showing the crank trigger, the cam position, the injector pulse, and the ignition. It shows the cam signal jump right when the motor cuts out. I will try and find a way to post the video here.

Thank You,

Jon

Jon, It sounds like you are not controlling the VVTi system with the Halltech. I spoke with someone else about running into a similar issue. The Halltech is most likely not set up for the signal frame, and I don't know that it can be with thier stuff. You are correct about what it happening, the cam is mechanically moving 40 deg and the ECU is loosing sync of the engine. I hate to sound like I am trying to sell you something, but this is one of the reasons why our EFI systems are better suited for these 2ZZ engine compared to other stand-alone systems. We have all of this already figured out for the end user so all they have to worry about is just tuning the engine, and even then the base maps are usually very close. Our system works with all of the stock sensors and triggers. Your buddy can probably sell the Halltech quickly on eBay or something to help him offset the cost of getting into something else. Feel free to call us or email me here at DRS if you need any other questions answered.

Kris