Seat Exeo TSI low boost?

[Smadmad]

Hi all

I'm having a boost problem that im struggling to solve. Car is a Seat Exeo TSI 2010. It's the same engine as the mk5 golf GTI.
Standard the car was producing aprx 8 PSi. Checked via OBD torque app
I checked the DV and that was split so got a GFB dv+ that made little difference. I replaced the PCV again still the same. I purchased a Superchips bluefin as they were running a offer.
Initially car felt good but I could hear a whoosh noise from about 4800 rpm then slowly boost started dropping off within a week to about 10-11 psi (Superchips said I should be getting 16-17 psi)
I borrowed VCDs and logged the boost and waste gate.
My actual boost roughly matches the specified boost up until the whoosh noise. My wastegate duty cycle is at about 65%. I have checked hoses and can't find anything. I have ordered a revision G DV but I'm lost.

Any help would be appreciated

[E-bmw]

My own personal opinion of your route is surely you would have been better using standard parts to solve the issue & then upgrading as you have no idea if the non-std parts are having an adverse effect on the issue.

[Smadmad]

I wont disagree with you however the issue was there before I did anything. I used a aftermarket DV as the OEM ones are renowned for splitting but I'm getting the latest revision because the GFB DV+ makes the car feel jerky.

[GreenV8S]

You have a misbehaving waste gate, or a misbehaving dump valve, or a leak. The problem might be with the valve itself, or whatever is controlling it. It shouldn't be too hard to disable either valve for a quick test, with due care to avoid overboosting.

[Smadmad]

The boost is meeting the ECU specified level but also telling the wastegate to open. So the ECU is lowering boost. Once I have fitted the diverter valve I'll check fuel pressure specified and actual as checking long term fuel trim it's running at +14%

[p4cks]

Common issues on these are the diverter valves, can result in problems with boost and low power as you're describing. Easy to fit too

[Smadmad]

I'm fitting a new diverter after fitting a GFB dv+ one but it's not the diverter valve as its meeting ECU specified boost and not pointing to a boost leak.

Edited by Smadmad on Thursday 13th February 20:31

[GreenV8S]

Smadmad said:

I could hear a whoosh noise from about 4800 rpm then slowly boost started dropping off within a week to about 10-11 psi

Smadmad said:

The boost is meeting the ECU specified level

Surely these can't both be true.

[Smadmad]

Sorry I didn't make it clear. Up until I can hear the whoosh noise its meeting ECU specified level of boost. After that boost drops below that level. I think that's the diverter valve( I'll find out once I have fitted a new valve)
The ECU specified is low at about 11-12psi. It should be higher.
Why is the ECU throttling boost? In order to meet the ECU specified level the ECU is opening the wastegate as I can see a low duty cycle between 55-65%.

[GreenV8S]

Smadmad said:

Sorry I didn't make it clear.

To be honest you're still really not.

Smadmad said:

Up until I can hear the whoosh noise its meeting ECU specified level of boost. After that boost drops below that level. I think that's the diverter valve( I'll find out once I have fitted a new valve)
The ECU specified is low at about 11-12psi. It should be higher.
Why is the ECU throttling boost? In order to meet the ECU specified level the ECU is opening the wastegate as I can see a low duty cycle between 55-65%.

If the ECU's boost target is lower than you want, you need to update the ECU's boost target.

If the ECU is opening the wastegate when the system is below the boost target it may need recalibrating, or perhaps it's getting an inaccurate MAP signal.

[Smadmad]

The specified boost target was fine when I first loaded the map however as I already said it started to drop off and lowered the specified target because the ECU is unhappy with something. Its lowering boost via the wastegate to match the specified target. I'm trying to prove exactly what the problem the ECU is detecting but not throwing up a code.

[GreenV8S]

That makes more sense now.

If you can see the ECU has lowered the boost target and the engine is achieving the target the ECU has set, the problem is related to the ECU or its sensor inputs and nothing to do with the dump valve, waste gate or induction hardware failing to meet that target.

Hence you need to look for fault codes, sensor inputs out of range or just a bad map in the ECU. Given that the ECU is modified, the people who supplied your custom chip would be the people to ask.

[Smadmad]

I'm getting no fault codes. The car was doing the same thing without the remap. I'm going to log fuel pump pressure at the weekend to check that as after looking at the vcds logs Superchips said it looks like a fuelling problem. The Cam followers are a common fault on these engines.
I'm just really confused as my long term fuel trim is 14% which would indicate a higher air to fuel mixture

Edited by Smadmad on Saturday 15th February 09:34