turbo knowledge needed

therealjt · 07-29-2009, 03:08 PM

We just bought a 1998 VW passat with the 1.8l turbo.
I can hear the turbo spool up fine but I have zero boost.
I have pressurized the vac lines with no leaks.
Anyone worked on these or have general turbo knowledge?

wastegate maybe?

desertT1 · 07-29-2009, 03:12 PM

Does it have a boost gauge? In my SRT4, one of the solenoid lines popped off from the pressure and I lost all boost. Make sure there aren't any lines that could have been missed, I did it.

shadawg · 07-29-2009, 03:15 PM

VWvortex.com is your friend.

go to forums.

Meph · 07-29-2009, 04:18 PM

Install a boost gauge. You might have a leak when running. My Eaton S/C runs at 6-7psi of boost, if there was a leak due to design it'd still wind up but I'd get nothing from it. So it'd sound all nice but lack in performance.

therealjt · 07-29-2009, 10:01 PM

actually installed a boost gauge today and nothing, been getting alot of info at passatworld.... sound like i need a new wastegate and should be able to pull out 14lbs boost after that. we just got the car for cheap

i actually pulled the turbo so i could check out the wastegate

Hammersmith · 07-30-2009, 10:51 AM

Def check out the forced induction forums on Vortex, that being said I have a few questions..

How do you know you're getting zero boost? Are you sure it's zero and not just low?

There's something in these cars called an N75 valve and they are pretty common failure point as is the actual diverter valve.

Both should be throwing a code if not a CEL, if you go to the dealer and get is scanned they could tell you if either is bad or has faults. If you don't want to go down that road I would again hop on VWVortex, go to the regional forums for your area, and ask if there's anyone local to you with VAGCOM that could scan your car for you. Most VW guys are cool and if they can help out another dubber they will so it's pretty likely that you'll get a response but it's also Vortex so you be prepared to get flamed as well

Alternatively if you own a laptop you could go to Ross-Tech: Home and buy the software and diagnostic cable yourself and do your own scanning.

You're call...

therealjt · 07-30-2009, 01:58 PM

I have a boost gauge installed and it reads zero when it should have boost.

i dont think the n75 is the problem as i have unhooked it (its a boost regulator) and still no boost.

I pulled the turbo and got to the wastegate, i am thinking the problem lays there. the actuator rod is moving with slight acceleration, i have tightened up the rod and am getting ready to put it all back together

07-29-2009, 03:08 PM	#1 (permalink)
therealjt Seasoned Member Join Date: Mar 2008	turbo knowledge needed We just bought a 1998 VW passat with the 1.8l turbo. I can hear the turbo spool up fine but I have zero boost. I have pressurized the vac lines with no leaks. Anyone worked on these or have general turbo knowledge? wastegate maybe?

07-29-2009, 03:12 PM	#2 (permalink)
desertT1 2 Infinity and Beyond! Join Date: Apr 2008 Location: Vail, AZ	Does it have a boost gauge? In my SRT4, one of the solenoid lines popped off from the pressure and I lost all boost. Make sure there aren't any lines that could have been missed, I did it. __________________ Feedback

07-30-2009, 10:51 AM	#6 (permalink)
Hammersmith Seasoned Member Join Date: Aug 2007	Def check out the forced induction forums on Vortex, that being said I have a few questions.. How do you know you're getting zero boost? Are you sure it's zero and not just low? There's something in these cars called an N75 valve and they are pretty common failure point as is the actual diverter valve. Both should be throwing a code if not a CEL, if you go to the dealer and get is scanned they could tell you if either is bad or has faults. If you don't want to go down that road I would again hop on VWVortex, go to the regional forums for your area, and ask if there's anyone local to you with VAGCOM that could scan your car for you. Most VW guys are cool and if they can help out another dubber they will so it's pretty likely that you'll get a response but it's also Vortex so you be prepared to get flamed as well Alternatively if you own a laptop you could go to Ross-Tech: Home and buy the software and diagnostic cable yourself and do your own scanning. You're call... __________________ Mr. President! We must not allow a mine shaft gap!

07-29-2009, 10:01 PM	#5 (permalink)
therealjt Seasoned Member Join Date: Mar 2008	actually installed a boost gauge today and nothing, been getting alot of info at passatworld.... sound like i need a new wastegate and should be able to pull out 14lbs boost after that. we just got the car for cheap i actually pulled the turbo so i could check out the wastegate

07-30-2009, 01:58 PM	#7 (permalink)
therealjt Seasoned Member Join Date: Mar 2008	I have a boost gauge installed and it reads zero when it should have boost. i dont think the n75 is the problem as i have unhooked it (its a boost regulator) and still no boost. I pulled the turbo and got to the wastegate, i am thinking the problem lays there. the actuator rod is moving with slight acceleration, i have tightened up the rod and am getting ready to put it all back together