My vanos is stuck on

[JGood]

the case shouldn't get so hot that you can't touch it. Shouldn't matter if it's touching the car or not.

could the vanos unit be faulty? as you've discovered, it always gets 12v, and the ECU simply grounds it to turn it on. maybe the vanos unit itself is shorting out.

I'm checking for ground with the car running and the vanos solenoid unplugged (I'm actually checking for ground from the vanos plug on the wire harness). So I'm putting my positive and negative multimeter probes on both pins in that connector, and it's getting 12v at all times. So the solenoid has no interaction, it's unplugged.

Very good idea though, I never would have even thought of that.


I grounded my case very well, it made no change.
I found the pin 7 wire behind the DME plug, and pulled it until the connetor at the solenoid started puling back through the harness. I did the same thing with the positive wire. Both moved independently of all of the other wires. This proves the wires aren't cut or smashed or melted together or anything like that, so the harness should be good.


I'm getting a known good 506 DME, putting my chip in it, and trying it in my car tonight.


I always get the weird problems. Huge thanks to Matt / TRM. He's been helping me via PM's basically parallel to this thread, and even sent me a custom chip to try.

[nando]

the case shouldn't get so hot that you can't touch it. Shouldn't matter if it's touching the car or not.

could the vanos unit be faulty? as you've discovered, it always gets 12v, and the ECU simply grounds it to turn it on. maybe the vanos unit itself is shorting out.

[JGood]

Just read my owners manual for the meter. It says it will beep if the resistance is less then 35 ohms, and will not beep if it is over.

So my was beeping intermittently, and read 36 ohms when I looked at it. That seems strange. Maybe it's right on the border? I'd think if the wire was shorting, it would be either full continuity or no continuity.

This is so frustrating...

[hoveringuy]

Ehh, not without the DME. I unplugged the DME, then tested continuity through the harness plug that the DME plugs into. So there should be no continuity to that one wire, it should run straight to the solenoid plug without touching anything else.

True dat.

[JGood]

All of those pins run through a MOSFET array which is how the ECU chip controls switching power.

Ehh, not without the DME. I unplugged the DME, then tested continuity through the harness plug that the DME plugs into. So there should be no continuity to that one wire, it should run straight to the solenoid plug without touching anything else.

[hoveringuy]

I checked for continuity between pin 7 on the harness at the DME (that's the vanos wire) and chassis ground, didn't see it. But plugging into the other pins on the harness plug and checking for continuity to pin 7 caused my multimeter to beep intermittently on at least 2 of the other pins. It was beeping intermittently, approximately once per second, as opposed to one long beep for the duration of the time that the leads are touching, which I thought was strange. An example was pin 2, which is for the ICV 'close control'. It registered as 36 ohms resistance (or maybe it was 36k, I forget). Either way, why would they be connected in any way? Oddly enough, the diagrams I have posted above also show pin 2, to the ICV. Maybe they got pinched together and are contacting somewhere in the harness? If that's the case, FML.

I wouldn't put too much stock in continuity readings between those pins. Is pin 7 grounded so that it lights a 12v LED? All of those pins run through a MOSFET array which is how the ECU chip controls switching power.

[JGood]

If I unplug my solenoid at idle it will stumble and idle like crap, too. That's not because it's engaging the VANOS when it's not supposed to, but because the ECU checks the solenoid when it starts. It needs to see that load.

Only way around that is to put a 100Ohm power resistor in there to satisfy the ECU.


Edit: Re-read and you never said it stumbles at idle. Never mind! Checking for +12v at the harness with the multimeter like you mentioned will work.

Mine does stumble at idle if I start the car with vanos unplugged, then plug it in.

I just now took it for a drive with the vanos plugged in. There's no question about it, the vanos is stuck on with the solenoid plugged in. Mid range is great and it does not pull for shit up top. I'm 110% sure. I drove it to work today unplugged, and it was so dead in the middle, and pulled so much harder up top. I really don't need to see voltage to verify it.

[JGood]

I checked for continuity between pin 7 on the harness at the DME (that's the vanos wire) and chassis ground, didn't see it. But plugging into the other pins on the harness plug and checking for continuity to pin 7 caused my multimeter to beep intermittently on at least 2 of the other pins. It was beeping intermittently, approximately once per second, as opposed to one long beep for the duration of the time that the leads are touching, which I thought was strange. An example was pin 2, which is for the ICV 'close control'. It registered as 36 ohms resistance (or maybe it was 36k, I forget). Either way, why would they be connected in any way? Oddly enough, the diagrams I have posted above also show pin 2, to the ICV. Maybe they got pinched together and are contacting somewhere in the harness? If that's the case, FML.

[hoveringuy]

If I unplug my solenoid at idle it will stumble and idle like crap, too. That's not because it's engaging the VANOS when it's not supposed to, but because the ECU checks the solenoid when it starts. It needs to see that load.

Only way around that is to put a 100Ohm power resistor in there to satisfy the ECU.


Edit: Re-read and you never said it stumbles at idle. Never mind! Checking for +12v at the harness with the multimeter like you mentioned will work.

[JGood]

You can't neccesarily just check continuity to ground on the plug because it's going through a MOSFET. There will be resistance. Get a 12v LED at Radio Shack. Connect the +12v side to the battery, connect the (-) side to the ground side of your solenoid. Tape the LED to your wiper arm.

I was going to plug both leads of the multimeter into the vanos harness plug, one ground and one positive, then measure voltage. Should be +12v when engaged, 0v when disengaged, no?

I'm not expecting to see chassis ground continuity in the vanos plug. That may be the case, but as you said, might not prove anything at all.

If it is truly stuck on disconnect the ECU from the harness and check for shorts to ground.

You mean connect my multimeter to the harness wire that engages vanos (pin 7 at the DME plug), and check for continuity to anything else (chassis ground and other harness wires)? That makes sense to me, and was one thing I wanted to try.

It's also possible that the electrics are working fine but the solenoid is physically stuck. Unscrew it and check that the plunger is free.

If that were the case, I would not get a significant power increase up top by simply unplugging the solenoid. It would also not create a change at idle when simply plugging the vanos solenoid in (it stumbled and almost stalled, but a restart of the engine allowed it to idle smooth again).

[lifeiskaos]

While I'm blabbering...

How hot are these DME's supposed to get? I know mine gets so hot that I can barely hold it. The case is not grounded to the car, just laying in my glovebox. Do either of these things sound bad? I didn't think they should get that hot, and I hope it doesn't need to be grounded to operate properly. It'd been running fine other then this vanos issue, for the last 2 years.

They don't need to be grounded, but it helps a bit in heat dissipation to be bolted in

[hoveringuy]

You can't neccesarily just check continuity to ground on the plug because it's going through a MOSFET. There will be resistance.

Get a 12v LED at Radio Shack. Connect the +12v side to the battery, connect the (-) side to the ground side of your solenoid. Tape the LED to your wiper arm.

If it is truly stuck on disconnect the ECU from the harness and check for shorts to ground. It's also possible that the electrics are working fine but the solenoid is physically stuck. Unscrew it and check that the plunger is free.

[JGood]

While I'm blabbering...

How hot are these DME's supposed to get? I know mine gets so hot that I can barely hold it. The case is not grounded to the car, just laying in my glovebox. Do either of these things sound bad? I didn't think they should get that hot, and I hope it doesn't need to be grounded to operate properly. It'd been running fine other then this vanos issue, for the last 2 years.

[JGood]

If the DME is sending signal to activate vanos, that might mean it thinks vanos is engaged, which means it's not giving me the proper maps in the top end, even when I have vanos unplugged? So although I'm getting more power up top, it' might not be nearly what it should be? Or maybe it uses the cam position sensor to decide where the cam is, and what map to use for map selection, in which case I'm already getting max power up top with vanos unplugged...

I hope there's even more top end power to be had when this is all straightened out :)

Are there any diagrams or articles out there that describe this kind of stuff, how these DME's work?

[JGood]

ECU will complete a ground to the solenoid. Solenoid should always have +12 volts with ignition.

How do you know what the VANOS is doing?

That matches my finding as well (post #3, not the 1st post). I know what vanos is doing because I can feel it. I haven't checked with a multimeter that the DME is or isn't cutting ground, but I'm 99.9% sure it is.

Unplugged: No midrange, pulls hard above 5k, espeically around 6k.
Plugged in: Lots of low end torque, doesn't pull as hard above 5k

It's not placebo effect, it's a very noticable difference. At least 25hp or so.

If the car is running, and I plug vanos in, it stumbles. This is at idle, when vanos should not be operating. That proves it's engaging at idle.