Anti Shudder Valve shutting down engine

[Davob]

I have been posting on the blown turbo thread but thought I should start my issue here ( i hope the MODS don't mind)

I have a passat 1.9 tdi highline. The car was going great and then one day after driving it all morning, I got back into the car and got the "emissions workshop" light and the car would go to tickover and then die within around 3 to 5 secs.

It was taken to the garage who replaced the EGR valve and when I went to pick the car up it had the same fault. After 4 more days then said that it was a problem with the ECU and it needed replacing which was beyond their means.

So, to get the car where it would start they have removed the vacuum hose from the anti shudder valve and blocked it off with a bolt. The car will run but without the boost therefore, it is very low power.

If with the engine started I put the vacuum hose back on the anti shudder valve I can see it shutting the valve and shutting down the engine.

Does anyone have any ideas on this, they would be much appreciated. One thought was that they might have mixed up the vacuum hoses from this valve and the one for the turbo acctuator, does this sound feesible? Would it be ok to swap them round to try or would this cause an issue with the engine.

[Crasher]

Disconnecting and plugging the line (or even not plugging it) will not affect the vacuum system control for the boost unless the vac line was unplugged and the shudder flap solenoid was stuck open so bleeding off all the vacuum. It sounds like a vacuum hose connection issue to me.

[Davob]

Hi Crasher,

Thanks for that.

When I take a look, the vacuum pipe is off (as mention earlier) and the shudder flap is open, therefore, it is like what you say, it is bleeding off all the vacuum.

on a side note, when I take the bolt out blocking the vacuum hose and leave it open the car actually runs better. albeit, still no boost. Does that make any sense?

[Crasher]

You need to check the vacuum pipe layout.

1. Vacuum unit for shut-off valve
2. Exhaust gas recirculation valve (mechanical)
3. Exhaust gas recirculation valve (N18)
4. Brake servo
5. Non-return valve
6. Tandem pump
7. Cylinder head
8. Intake manifold
9. Intake manifold change-over vacuum unit
10. Intake manifold flap change-over valve(N239)
11. Air cleaner
12. Charge pressure control solenoid valve (N75)
13. Non-return valve. White connection to charge pressure control solenoid valve item 12 and to vacuum reservoir
14. Vacuum reservoir
15. Charge air cooler
16. Pressure unit on turbo
17. Turbocharger

[Davob]

Hi Crasher,

Thanks for the infroamtion, much appreciated.

Regards

Dave

[Davob]

any ideas for the best place to get a replcement ECU or refurbished one as they doesn't seem to be anywhere over here in Ireland that does it.

[Iamtony]

try traynors up north there usually good for second havd stuff. Ring them monday and they deliver to Dublin every Tuesday. But I wouldn't trust the garage telling you its the ECU just yet, sounds like they didn't have a clue and just fobbed you off.

[Davob]

They checked the vacuum systems and said that this was ok, no problems. There was an issue with the N75 valve and it was replaced and now the anti shudder valve is working ok with the vacuum hose connected. However, the car still gets the "emissions Workshop" on start and runs with no turbo.

The garage indicated it was either an issue with a broken wire or the ECU. They said that it would take a long time to test the wiring therefore, big money. So, I was wondering if it is best to get the ECU checked first, as it may be the cheapest option.

Cheers

[yaman]

It's unlikely to be a faulty ECU, but the problem area
can be identified by running a fault-scan. and good
interpretation, IE: post them here.

Have you tried re-booting, by disconnecting the battery
(negative) for 5minutes?

Iamtoney is right about Traynors (Armagh)

Regards
Jim

[Davob]

Hi Jim,

Thanks for the reply, much appreciated. I will try disconnecting the battery tomorrow. Would the VW specailist who was looking over the car not have tried this? or are the obvious things overlooked sometimes.

The fault codes if I can remember correctly are (i will confirm these with the mechanic on monday)

17957 fuel pump relay (J17) open short to ground P1524 - Intermittent
17849 EGR valve (n18) open circuit or short to ground p1441 intermittent

17957 - boost pressure regulation valve (N75) open short to gorund - P1549 intermittent

Thanks to everyone for all of your help.