No boost till 2k rpm

[Taizer]

Hey people

I own a p130, it's got a egr delete and the n75 has been simplified.

I'm getting no boost till 2k rpm then it goes, it's almost like driving a sdi up to 2k ?

I've replaced all vac hoses and vac tested everything for leaks

I've put chemical metal around the tandem pump vac pipe

I've checked the actuator is moving fine

All OWV are working fine

Checked for boost leaks (not that it will cause it to boost from 2k up)

I'm at a dead end and dunno what to do next.

Hoping someone can help me get my car back to its potential

Thanks

 

[Mozambiquer]

Hey people

I own a p130, it's got a egr delete and the n75 has been simplified.

I'm getting no boost till 2k rpm then it goes, it's almost like driving a sdi up to 2k ?

I've replaced all vac hoses and vac tested everything for leaks

I've put chemical metal around the tandem pump vac pipe

I've checked the actuator is moving fine

All OWV are working fine

Checked for boost leaks (not that it will cause it to boost from 2k up)

I'm at a dead end and dunno what to do next.

Hoping someone can help me get my car back to its potential

Thanks

What year car? None of the mk3 cars I know of have a tandem pump. Sounds like sticking vnt vanes or something like that. Also could be worn turbo bearings.

 

[Vince Waldon]

Probably need to say a bit more about what you mean by "n75 has been simplified", since the n75 is key to how boost is controlled.

Per the low-power HOW-TO in my sig, you'll also want to ensure the actuator starts moving at the correct vacuum input (3-5") and hits the stop at the correct vacuum input (18-20"). If these values are off boost will be dramatically affected.

 

[Taizer]

What year car? None of the mk3 cars I know of have a tandem pump. Sounds like sticking vnt vanes or something like that. Also could be worn turbo bearings.

It's a 2005, I posted it in the wrong bit but didn't know how to delete it, I've tried the Mr muscle trick with nothing

 

[Taizer]

Probably need to say a bit more about what you mean by "n75 has been simplified", since the n75 is key to how boost is controlled.

Per the low-power HOW-TO in my sig, you'll also want to ensure the actuator starts moving at the correct vacuum input (3-5") and hits the stop at the correct vacuum input (18-20"). If these values are off boost will be dramatically affected.

The n75 is the only control valve I have basically, gets vac from tandem, then lines to air box and actuator.

I've checked that the actuator moves freely and it does, is the input in psi that you're telling me to check?

 

[Vince Waldon]

The specs are for vacuum, so given in inches (of mercury) .

You'll need a hand-powered vacuum pump with gauge, attached directly to the actuator. Add vacuum, see when the actuator starts moving and then keep adding vacuum to see when it hits the end stop. If it's out of spec the threaded actuator rod will need to be loosened and then lengthened or shortened to dial it in.

It's good that the actuator is moving, but it also has to respond accurately to specific vacuum settings in order for the ECU to be able to properly control boost.