My vanos is stuck on

[matt]

I will take that as a compliment. Thank you, sir.

[hoveringuy]

The evap valve is PWMed. The duty cycle depends on how much extra fuel vapor the engine can handle at a given moment. IE at high throttle, it will be more open because there will be more air flow to absorb the vapor and keep the motor running smoothly.

Don't worry too much about the voltage you see on the VANOS line. The nature of a MOSFET solid-state low-side driver is that it may leak voltage, but it won't drive significant current through its load (the VANOS) without the proper signal. Thats why you got the correct result with a load (LED) but an incorrect result without a load (DMM in voltage mode).

Spoken like a geek. The MOSFET can look like a closed circuit at the milliamp levels of current used by the multimeter but for any significant amount of current (like driving the solenoid) it will be open.

The LED draws enough current to tell you what's really happening.

[JGood]

Don't worry too much about the voltage you see on the VANOS line. The nature of a MOSFET solid-state low-side driver is that it may leak voltage, but it won't drive significant current through its load (the VANOS) without the proper signal. Thats why you got the correct result with a load (LED) but an incorrect result without a load (DMM in voltage mode).

Thank you!

[nando]

okay, that helps - thanks. making a PWM based EVAP map from scratch isn't easy when you don't know when it's supposed to open. :p

[matt]

The evap valve is PWMed. The duty cycle depends on how much extra fuel vapor the engine can handle at a given moment. IE at high throttle, it will be more open because there will be more air flow to absorb the vapor and keep the motor running smoothly.

Don't worry too much about the voltage you see on the VANOS line. The nature of a MOSFET solid-state low-side driver is that it may leak voltage, but it won't drive significant current through its load (the VANOS) without the proper signal. Thats why you got the correct result with a load (LED) but an incorrect result without a load (DMM in voltage mode).

[nando]

matt, do you know anything about the operation of the EVAP valve?

PWM can still be on off, but it was really just a guess based on the wiring diagrams.

[JGood]

Back to the drawing board...

Why can't I get a correct reading on a multimeter then? If it's 12v on, or 12v off, I should see that....

[matt]

There is no PWM in the M50TU. It's on or off. Same with the MS41 based M52. The MS42 and above have real PWM cam control.

[nando]

at a certain duty cycle, the solenoid would be on/off anyway. I don't know, I was told the evaporative purge valve was PWM and I had thought it was simply on/off too.

[JGood]

Interesting. Why would they use a PWM signal? I'd think you'd want constant on or constant off to the solenoid (which uses on or off to allow oil pressure to pass through vanos or not pass through).

[nando]

LED's don't lie?

I mounted a 12v LED on my steering column, and spliced it into the + and - wires of the vanos harness connector, up closer to the ECU. With the vanos plugged in, I drove around. It lit up exactly when it should... only after moderate thottle load, between idle and 5200 RPM's. At light throttle load, or above 5200, it never lit. So my vanos is fully functional.

Weird thing is, I then hooked my multimeter up to the LED, and drove around. It read 12-14v at all times, except for a split second every time the LED turned on or off, it dropped to zero. Can any of you EE's explain that? haha

I think it's a PWM signal, at least the ETM diagram suggests as much. the DMM won't really be fast enough to read the signal though.

[JGood]

LED's don't lie?

I mounted a 12v LED on my steering column, and spliced it into the + and - wires of the vanos harness connector, up closer to the ECU. With the vanos plugged in, I drove around. It lit up exactly when it should... only after moderate thottle load, between idle and 5200 RPM's. At light throttle load, or above 5200, it never lit. So my vanos is fully functional.

Weird thing is, I then hooked my multimeter up to the LED, and drove around. It read 12-14v at all times, except for a split second every time the LED turned on or off, it dropped to zero. Can any of you EE's explain that? haha

I guess when I disconnected the vanos, it just made the top end feel so much more powerful, since the bottom end was so dead. I guess my butt dyno needs calibrated.

[JGood]

I have a vanos plug and full length of wire if the harness turned out to be bad. You'll have to splice it in, but the M50 harness makes that pretty easy.

Awesome! Actually, having that would make even just testing things 10x easier. If this DME doesn't work tonight, I'll be in touch. Thanks.

[JGood]

Oh, and I believe me getting 36 ohms resistance between pin 7 (vanos) and pin 2 (ICV) is due to the fact that both of those components were plugged in, and share the same positive connection. So the current from the multimeter was traveling through the ground of the vanos, to the positive, which meets at a positive junction with the ICV, then through the ICV negative back to pin 2. So it saw a connection, but had the 36 ohms resistance caused by the solenoid and ICV. That's my guess. I'll unplug the vanos solenoid and retest, to verify.

[nando]

I have a vanos plug and full length of wire if the harness turned out to be bad. You'll have to splice it in, but the M50 harness makes that pretty easy.