Primary Boost dump (sequential)
 

I’ve been hunting down a leak of some sort. What happens is the primary will pull hard til about 3000rpm while building boost, hit .9bar but by then it feels like it’s dumping it. It then transitions as usual and pull hard .9bar to redline.

I can’t seem to figure out the 3000-4000rpm boost dump, it just feels like I’m losing the boost without any obvious noises. The gauge will climb to full boost but by the time it reaches 0.7 to making 0.9 it feels like it’s escaping and the hard pull just weakens only at that point. Everything else is fine especially after transition and it’s certainly not the grounding hesitation.

Where’s a good place to start looking? BOV or CRV leak? Basically feels like it’s dumping the boost despite having good readings on the gauge (full boost).

And sometimes after making 2 pulls it works perfectly again and you’ll feel the punch at 3000-4000rpm... anyone?

It is obviously boosting because the build up is enough to pull you to the seat only when reaching close to full boost at primary will you feel it weaken as you watch the gauge reach full.

Replaced BOV and CRV and retightened and replaced vacuum hoses. Cleaned Boost sensor as well as tightened and resealed the y-pipe.

Now it happens for just the first pull, then it’s back to normal again each time after that. Any ideas why it’s intermittent and where to look?

Hard to say. What ECU do you have on the car?

Could be the solenoid controlling the CRV isn't switching over when it should. You can cap the CRV and see if that makes a difference.

Dale

Hi Dale,

i just got to work this out yesterday, turned out a part of the intake hose was collapsing. I guess running less than 10 psi wasn’t a problem but sucking at 13psi was too much for it and the turbo was trying to make the boost (hence getting the 13psi reading) but the pull just wasn’t there.

I guess it was best to clean and retighten all of the hoses, solenoids and sensors to eliminate causes while the most obvious thing was the one left out unchecked.

most of the time I go through the most complicated solutions missing out on the most simple and obvious ones.