Hissing noise when take foot off gas pedal around 2k rpms

[davestampy1]

So I've joined this group to get to the bottom of this. The problem...
When I drive and the van Gets over say 2k rpms, If let go of the pedal slightly and the van hisses. It will continue to hiss until I move gas pedal position. If I lift foot off ever so slightly the van almost jults/ hesitates slightly.

I see on stub shaft there's a spring and washer. Does this move between acceleration and de acceleration?

Things I've done so far which have been a complete waste of time...
New turbo
New alternator
New pas pump
Belt and tensioner
Deleted egr and mapped out.

Each item above I've convinced my self was the problem and now I'm still sat here wondering what is it... any ideas?

 

[davestampy1]

Bump

 

[mmi]

A bit more background information would be helpful:

• What engine - engine code please (on sticker under dash)?
• What gearbox: DSG, manual?
• Age of the van - model year, mileage?
• Any fault codes?

When I drive and the van Gets over say 2k rpms,

On all gears?

New pas pump

Low or high pressure one?

 

[davestampy1]

Hi
Engine mount code CXGB 102hp

Manual 5 speed.

2017 80k miles

No faults codes its been like it for 2 years and hasn't gotten any worse.

Gears I'd say it's more noticeable up to 3rd gear.

Pas pump changed as in power steering pump, there's only one I belive thanks

 

[mmi]

Thanks.

If let go of the pedal slightly and the van hisses.

Would pressing the clutch stop the hiss?
Would the same happen starting to go downhill - thus naturally easing off engine/gearbox/powertrain load?
Engine mounts?

 

[davestampy1]

Thanks.

Would pressing the clutch stop the hiss?
Would the same happen starting to go downhill - thus naturally easing off engine/gearbox/powertrain load?
Engine mounts?

It will stop the hissing it I increase or decrease acceleration slightly. It will also stop if I put the clutch in. I've never tried it going down hill actually

 

[BognorMotors]

I’m sure we could help with diagnosis and fix but would obviously we’d need to see it. I can see you are in Surrey so not a million miles away. Shout if you want us to take a look.