Possible to run BEW anti-shudder valve on ALH software?

Redneck Truck

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I want my anti-shudder valve back on my TT, but I'd rather run an electric one than a vacuum actuated one. Does anyone know if such a conversion is possible without too much wiring or programming?
 

oilhammer

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outside St Louis, MO
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There are just too many to list....
The ALH is EDC15, the BEW is EDC16, there are many differences, and I do not think the outputs are even present on the ALH's ECU to make the throttle motor work... as it also is used in conjunction with the electric EGR valve, so it isn't just for shut-down smoothing.

You *may* be able to rig something up standalone that powers a relay to do something to make it work at start-up (open) and shut down (close) but since its operation is also dependent on its position via the built-in feedback it has, that may be more difficult than you (or I) think.
 

Redneck Truck

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2008 Touareg V10, 2001 Audi TTQ Roadster TDI 6-speed, 2005 Jetta Wagon TDI 6-speed
That is exactly the information I was looking for.

My EGR valve is eliminated and tuned out on my BEW and I don't believe the ECU sends power to that circuit anymore, but the anti-shudder valve still works as it should.

Since the motor is spring-loaded, I could theoretically apply 12v to the correct pins and max it in the closed direction. I know that the impedance of the vacuum valve on the ALH is some 16 ohms, so as long as the load on the motor circuit doesn't exceed that, I might be able to get away with it. I suspect that once the motor stops (throttle plate shut), the load will increase and could cook the circuit, so maybe a relay is appropriate.

My assumption is that the circuit that powers that vacuum valve is *only* energized for 2 seconds after you key off and at no other time. Is that accurate?
 

oilhammer

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On the ALH, the solenoid for the anti-shudder valve is energized for a short time, yes. Cannot recall if it is timed only, or if it waits until the RPM drops to zero... since the relay 109 powers down when you turn the key off, and therefor the ECU powers down, I would think it impossible to be by RPMs alone... and having experienced runaways with ALHs before, I can verify in the real world that must be the case. Because if the engine is spinning at 6000 RPMs, the valve won't stall the engine, it'll just make it hiccup, and it take right back off.

Is this a PD engine in your TT running an older ECU?
 

compu_85

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...since the relay 109 powers down when you turn the key off, and therefor the ECU powers down, I would think it impossible to be by RPMs alone...
Actually relay 109 powers down a few seconds after you turn the key off, just after the ASV is opened again. The ECU can hold that relay on, and is what the power for the ASV solenoid comes from.

-J
 

oilhammer

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That makes more sense! For some reason, I always pictured in my head a capacitor on the output leg of that circuit from the ECU that let "just enough" current to keep the solenoid open, being it wouldn't need as much to keep it there if it had been able to use full power to open it in the first place. Clearly I thought to much about that... (I have dreams that involve things that peak 'n hold.... :D ).
 

runonbeer

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I once asked Charlie (KERMA) about doing the exact opposite; running an ALH EGR/manifold on a BEW. His answer was the same: EDC16 won't do it.
 

Redneck Truck

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2008 Touareg V10, 2001 Audi TTQ Roadster TDI 6-speed, 2005 Jetta Wagon TDI 6-speed
You're talking about moving in the opposite direction, so it's understandable that wouldn't work. Compare to converting a color photo to black and white vs black and white to color.
 

turbocharged798

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May 21, 2009
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On the ALH, the solenoid for the anti-shudder valve is energized for a short time, yes. Cannot recall if it is timed only, or if it waits until the RPM drops to zero... since the relay 109 powers down when you turn the key off, and therefor the ECU powers down, I would think it impossible to be by RPMs alone... and having experienced runaways with ALHs before, I can verify in the real world that must be the case. Because if the engine is spinning at 6000 RPMs, the valve won't stall the engine, it'll just make it hiccup, and it take right back off.

Is this a PD engine in your TT running an older ECU?
This is pretty opposite from another post I read on here.

The was a member on here who monitered power to the N239 and shut the key off while coasting downhill to simulate a runaway. The N239 remained powered up until the engine stopped. He verified it and the ASV remained closed until the engine stops turning regardless of time.
 

compu_85

Gadget Guy
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Sep 29, 2003
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La Conner, WA
TDI
... None :S
The was a member on here who monitered power to the N239 and shut the key off while coasting downhill to simulate a runaway. The N239 remained powered up until the engine stopped. He verified it and the ASV remained closed until the engine stops turning regardless of time.
Cool! Have a link to that post?

-J
 
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