Another...Overboost protection is ruining my life....!

[JamesHarrold]

Thanks David....

Unfortuanatly I live in Norfolk and there are no forum members anywhere close to lend a hand, or donate an ecu for that matter.

I might get it out of the car tommorrow and dismantle it to see if its been played with.

Thanks for your words of encouragement....will keep at it...!

Cheers

James

[dest]

I replied to your other thread, and just read David's comment on this one, if you want to try my ecu and also get some motivation come over at the weekend
I too went through boost cut hell, so know exactly what you are up against

[JamesHarrold]

Its been a while since I posted anything about the bain of my life, so thought I would pick your brains again....

My car is still overboosting and cutting out due to the overboost protection....nearly ALL the time.
I fitted my vdo boost guage and am seeing 1.4 bar boost pretty much all the time (overboost in 4th at WOT and in all lower gears)

Why, on a standard, unmodified ecu am I seeing such high levels of boost? I have not played with the wastegate and have recently fitted a new wgfv.

Whats going on guys.....I am really tempted to give up soon, its been like this pretty much since I bought it in MARCH....!

Cheers

James

[AndyP]

Did you ever open the ECU and check the chips? If your seeing 1.4bar in all the gears then I'd say it has been chipped. Do you have a laptop that you could put VAG COM on? If you do that you could probably find out who chipped it. Have you done a boost leak test? If you havn't go a test kit I can send you one, PM me you details if your interested.

Andy

[JamesHarrold]

Hi Andy....

Thanks for the offer of a leak test kit, but have bought one and done a leak test and it holds over 1 bar of pressure with no hisses or bubbles

Dont have vag com, but have pulled the codes and constantly get 2224 (maximum charge pressure exceeded)

Had the ecu out today and had a look at it, doesnt look like it has been out before and no signs of it being opened up. Was kinda hoping it had a dodgy chip in it and therefore an easy fix, but still standard I think.

Any more ideas anyone?

[newsh]

Have you checked that you have a stock spring in the wastegate and its not shimmed or anything? Easy to take the top off and have a look.

[JamesHarrold]

Yep...had the wastegate of and checked the diaphragm and spring and all ok.
As I am constantly getting overboost protection kicking in does this mean an air leak increases the amount of air taken into the engine therefore increasing boost pressure?

Cheers

James

[AndyP]

Maybe the previous owner removed the chipped ECU before he sold it and left the uprated wastegate spring? To look at, it's hard to tell a std spring from an uprated one, try and get hold of a known std spring and try that.

[newsh]

pretty sure there's a pic of the stock spring on here somewhere. I have one in the garage too.

[newsh]

Wondering if there's something wrong with your wastegate plumbing, try connecting the turbo coldside directly to the wastegate with a straight piece of tube bypassing the WGFV altogether, plug the hose that goes back to the MAF tube, see if you still get 1.4 bar boost without ecu control. If you do then the WG spring is too stiff or there's another issue with the WG.

[JamesHarrold]

I have another spring in the workshop so will try that in the morning...although it looks exactly the same as the one I am using, will give it a go though, I am running out of ideas....and patience!

Thanks for the replies guys...will keep you posted....

Just a though.....When I disconnect my wgfv my guage is showing 0.6 bar boost not the usual 0.4 bar max....???????

James

[S2central.net]

IF the ECU is standard then I too suspect a faulty WG or beefy bedspring in there - or of course its connected wrongly.

1. WG valve could be stuck.
If you apply vacuum to the open port on the WG cap you should be able to lift the WG valve off its seat. Then quickly release the vacuum and you should hear it slide down the shaft with an audible thunk - then you know its moving at least.

2. WG valve could be too stiff - ie you are running on mechanical boost control with a bad spring
Disconnect the WGFV - the 2pin wiring plug just unclips... It should do two things to verify the ECU is somewhat sane... Firstly raise a faultcode that the WGFV is open ciruit and 2ndly your boost pressure should be approx 0.4bar maximum - that what a stock spring does if the plumbing is OK

3. If you dont get 0.4bar with the WGFV disconn'd then the WG spring itself may be wrong - or its just plumbed wrong.

The plumbing from turbo to WG via the WGFV on an ABY is as follows...

WGFV has three pipes -

Pipe #1 is nearest the WGFV electrical connection and should face the UK drivers side of the car when fitted correctly. Connects to wastegate.
Pipe #2 is directly opposite Pipe#1 and slides into the MAF pipe - this is ALWAYS under vacuum.
Pipe #3 points towards the ground and has the little link tube to the compressor housing on the turbo

I would check all the pipes to and from the WGFV that they are airtight and NOT blocked or have evidence of any bleed valves or other barnacles.

WHen the WGFV is OFF the solenoid should set an air path from Pipe#3 to Pipe#1. This presents boost pressure directly to the LOWER chamber of the WG and opens it under control of mechanical spring pressure alone. This is equivalent to applying vacuum to the UPPER chamber of the WG.

When the WGFV is ON the solenoid should set an air path from Pipe#2 to Pipe#1 - ie present vacuum to the LOWER chamber of the WG and keep the spring closed. In use of course the WGFV is modulated by variable duty cycle so that the pressure presented to the WG is controlled somewhere between full boost and full vacuum.

Other things to check------

- That there is no pipework attached to the upper chamber of the WG... Some of the old UR engines had this in place for an alternative method of boost control but its absolutely wrong on the 20V Turbo engine.

- That the throttle bypass valve is working OK... Should be shut until you apply vacuum to the control port.


HTH,

Paul

[JamesHarrold]

WOW

Thanks for that Paul....Will take my laptop out to the workshop and go through that little lot....Much appreciated..Really want to get this sorted then its the ecu off to you for a Homefry.

Let you know my findings tommorrow night

Cheers

James

[JamesHarrold]

Just spent the morning on the car...

Checked all the points Paul mentioned.

Wastegate spring is standard and screw in the cap has not been wound in at all.

By passed wgfv and getting 0.6 bar boost showing on the guage, so I took the metal cap off the top of the wastegate cover and wound the allen key bolt out until I had 0.4 bar mechanical boost (its now nearly at the top with only about 1 thread showing.
Have definately not sorted the problem, as I am sure I read somewhere that there should be 5 threads showing in the wastegate cover as standard (as mine was)

Anyway its not cutting out anymore, so at least I can drive it, but I am certainly not giving up. Has anyone got any other ideas, or know why I would have so much boost on a stock wastegate, spring and ecu?

Cheers

James

[S2central.net]

No probs James - I can sanity check your ECU when it gets here - before and after an upgrade...