Help needed with WGFV actuation voltage info

[newsh]

Hi All

I've got a strange thing going on with the WGFV actuation on my 3B. It seems to work ok with a stock valve but when I try a heavy duty valve I get no boost control, only spring pressure. I've tried with 2 different (S2 Bo type) HD valves and no joy. I've blown through the valves, operated the solenoid with a 12v battery and checked the correct operation and flow a few times and I'm sure everything is correct. Swapping back to an old stock valve works fine and I get my full boost back. It seems like maybe the ecu is not supplying enough current to open the HD valve..

Any ideas?

I think the WGFV gets a 12v feed and gets grounded by the ECU to actuate, is this correct?

[Jamo]

Have you got the right valve as they have alot that work at different voltages and these valves aren't s2bo types! Some of us were using them before Bo
What's the model number of the valve you bought

[newsh]

Yeah I know but I bought them from S2 Bo, and it was late and I couldn't remember what they were called

The valve says 12v on it, I need to go out to the garage and get the number off it.

[Billman]

i plugged both valves on the 12volt supply (stock N75 and HD one) and seen that the air flowing through the N75 is much more than the Mac ones. That is maybe why you are seeing different values or different boost profile.

If you got no boost control at all then you should check the connection again.

[S2central.net]

I have had problems with non Bosch N75 valves too - they don't all behave exactly the same way with regards port topology when open & closed. Behaviour I was seeing was wobbly/inconsistent boost all over the place with aftermarket 'HD' valve - swapped it out for Bosch N75 and all was grand.

You are correct that the 12V input stays active on the N75 and that ECU pulls other side to 0V to switch it over - I can't imagine it would require so much current as to cause a problem for the ECU - it goes through a fairly meaty looking driver with heatsink etc.

[newsh]

Valve number is 35A-AAA-DDBA-1BA

12V DC, 5.4W

I agree the N75 flows more air but I would say it easily flows enough to shut the WG and anyway I was under the impression that these valves were plug and play. I think I'll put one on the avant and see if it works, if so I guess there is a wiring problem on the 3B, maybe a high resistance connection. Can you do a VAGCOM output test on a 3B?

[S2central.net]

Yes - output tests work on the 3B with VAGCOM

Question - if factory N75 flows more air than aftermarket valve, why change it out - is it *that* much more durable than factory bosch item ?

[Billman]

actually it is much more durable than the bosch item.

I think you don't really need flow there jut the pressure difference but maybe because of the flow difference it needs DC adjustment.

[prj]

actually it is much more durable than the bosch item.

I think you don't really need flow there jut the pressure difference but maybe because of the flow difference it needs DC adjustment.

It does need DC adjustment.

As for durability - these valves fail because they are over 10 years old and because all sort of stuff gets into them.
Stock valve is perfectly adequate for even fairly silly boost pressures and costs little.

[Billman]

no one said they can't control big boost but they cost almost the same as the others and are plastic

[newsh]

It does need DC adjustment.

So it needs remapping?

[s2_bo]

Sorry to hear that your having probs still John.
No it does not need remapping.
I really doubt its the valves as i have sold about 100 so far and can only think of one other person that didnt get on with it and that was for a different reason.
They seam to work right across the board on most VAG turbo cars.
When i ordered the last batch my supplier said that the same valve is now also being used on the new Noble M600.

I tested these valves thoroughly on quite a few audis running various power and supply them with all the right fittings so that they are plug and play.
One of the main advantage is that the hose tails are brass not plastic.
If you like you can return both and i will refund you of course.

Billman how did you measure flow rate? Airline > valve > pressure chamber & gauge?

[Billman]

Billman how did you measure flow rate? Airline > valve > pressure chamber & gauge?

Primitive way of testing. Simply blowing though and actuate.

[newsh]

Resistance of N75 and Mac valve are very similar, approx 26 vs 28 Ohms
Measured voltage at valve on 3B, 11.75v. Actuated valve by grounding the other pin, valve clicks and voltage does not drop so supply circuit seems good. Went for a drive in 3B, GT3071, 1.5Bar spring MRC Map, getting max boost of about 1.5 bar spike and maybe 1.3 Bar thereafter (N75 gives 2Bar)
Fitted HD Mac valve to Avant running stock WG and Homefry, works perfectly, no reduction in boost.
Willl try output test tomorrow to see if there is a problem with the return line to ECU.

[newsh]

Sorry to hear that your having probs still John.
No it does not need remapping.

Hi Bo
As just posted, I now have one valve fitted to the Avant and working perfectly so I think it is something to do with the car. I get a surge of boost and then it drops off, weird..