Ive lost 3 pounds!

**.Mad Hatter.** · 11-23-2008 07:44 AM

of boost.

i generally spike pretty obviously at 17psi, now im lucky to make 13-15, and it certainly doesnt hold well enough.

nothing has changed. i changed my plugs, they are gapped at .32.

its due for an oil change, but i dont see that being the cause.

i think i need a new t stat, but it was up to temp when tested.

i cant all of a sudden see my spltr valve holding less boost, and i dont want to increase the spring tension if i dont have to.

your thoughts?

**djwimbo** · 11-23-2008 09:20 AM

Boost leak? Maybe in the vac line going to the DV? Does it sound any different, or just less boost?

**Tifun** · 11-23-2008 11:57 AM

Sounds like we have similar problems. I am down about 3-5 psi and the car overall doesn't feel right.

**.Mad Hatter.** · 11-23-2008 03:50 PM

doesnt sound any different.

the temp has dropped alot but like i said, the car is up to temp. t stat needs to be replaced, but again, car was warm when tested. i tested in 3rd, 4th, and 5th. it BARELY got up to 15psi, it should easily jump to 15 and build and spike at 17, im simply not seeing that. ill check the vac. line tomorrow or tuesday.

mpg seems to be around the same ill note, im totally lost.

**.Mad Hatter.** · 11-24-2008 01:54 PM

looks like all hoses around the DV are secure, i tightened them just to make sure. did a few more runs today.

generally, i can hit 15psi real quick and then it spikes to 17psi.

now, i will hit 10-12 psi quick and then it spikes...sloooowly, at 15psi...and hits a wall.

**mike-2ptzero** · 11-24-2008 02:37 PM

This happens every winter for people that run a N75 valve. In very cold temps you will notice that you end up running less boost because the N75 does not adjust to force the turbo to stay at a set boost level. The much lower IAT's are the reason you see lower boost readings at the IM.

**.Mad Hatter.** · 11-24-2008 08:16 PM

wow...that was easy...

thanks mike, appreciate the knowledge. it makes sense because im not losing a great deal of boost, its minimal. initially the air temp crossed my mind, but i figured it wouldnt cause any issues.

**0000_a4** · 12-05-2008 09:03 AM

Originally Posted by mike-2ptzero

This happens every winter for people that run a N75 valve. In very cold temps you will notice that you end up running less boost because the N75 does not adjust to force the turbo to stay at a set boost level. The much lower IAT's are the reason you see lower boost readings at the IM.

Mike I am having the same issue with my car and your information really made sense. However I am only boosting at 10 psi from 17 holding on 15. I recently replaced my n75, all the pcv system replaced, boost leak tested with no leaks and no codes. Hope you can help me with this one. Thanks

**mike-2ptzero** · 12-05-2008 10:51 AM

Originally Posted by 0000_a4

Mike I am having the same issue with my car and your information really made sense. However I am only boosting at 10 psi from 17 holding on 15. I recently replaced my n75, all the pcv system replaced, boost leak tested with no leaks and no codes. Hope you can help me with this one. Thanks

Have you tried resetting the ecu? Could just be in a limp mode. Also check your block 032 readings and maf readings with a vagcom, could be that the maf is on its way out causing the loads to be lower and this will make the car produce less boost.

**0000_a4** · 12-05-2008 11:58 AM

Thanks for replying so quick mike I will do the readings tomorrow. Btw, our temp here in chicago is like 7 degrees could that be a factor to drop the boost about 7 psi though?

**mike-2ptzero** · 12-05-2008 12:23 PM

Originally Posted by 0000_a4

Thanks for replying so quick mike I will do the readings tomorrow. Btw, our temp here in chicago is like 7 degrees could that be a factor to drop the boost about 7 psi though?

Well that is pretty cold but its really hard to say if that would cause a 7psi drop.