Help! Intermittent boost loss..

[s4mmie]

Bit of a weird one this one.. It happened to me driving to the shops tonight.. putting my foot down in second and where it would normally spool up to 17-18psi, I was barely able to coax 4-5psi out of it and it felt sluggish as hell. This happened a few times.. then it was good as gold again. Then coming back home, climbing a hill under load in 3rd it overboosted to about 25psi before I had a chance to back off..

No codes.. I can't hear any unusual noises.. had a quick look at the hoses, they look fine but it's dark so I'll have another look tomorrow. The missers did say that the car felt like it was in a gear higher accelerating onto the highway home for the last day or so too.. Any other ideas or places to look? Could it be the dv or n75?

[h100vw]

Bit of a weird one this one.. It happened to me driving to the shops tonight.. putting my foot down in second and where it would normally spool up to 17-18psi, I was barely able to coax 4-5psi out of it and it felt sluggish as hell. This happened a few times.. then it was good as gold again. Then coming back home, climbing a hill under load in 3rd it overboosted to about 25psi before I had a chance to back off..

No codes.. I can't hear any unusual noises.. had a quick look at the hoses, they look fine but it's dark so I'll have another look tomorrow. The missers did say that the car felt like it was in a gear higher accelerating onto the highway home for the last day or so too.. Any other ideas or places to look? Could it be the dv or n75?

Could be the wastegate is sticking, the wiring for the N75 can break but that should cause low boost not high. a Split pipe after the N75 would cause constant high boost.

Disconnect the plug off the N75. That will give you actuator pressure. So if it boosts more than 6-7psi there's something wrong below the N75.

Gavin

[s4mmie]

Thanks gav, I'll give it a try tomorrow and see how I go

[Jmac]

Ecu will trim it down if it has had an overboost. You will have codes if that is the case. Also make sure the pipe from N75 hasn't turned to chewing gum to the actuator, anything obstructing the pressure to the actuator will cause the gate to stay shut longer and spike., also pipe of and apply some air pressure to the actuator and see that it moves freely.
By the way you don't need a cel to have codes there
Ta
Jmac