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no boost or vacuume?


88-cnqst-tsi
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I have a Hawk vacuum and fule pump tester so i hooked it up the the stock WG input on the OVC hard line and had my dad rev the engien but the needle didnt move for boost or idle. Could i have a leak somewhere? some causes might be the hardended cracked cupping for the TBI intake and everything is stock and old. the vacuum and fule pump tester was found in my garage hiddin in a box for a while but if a blow or suck on the tube it reads vacuum and psi. http://www.ebay.com/itm/709-CAL-CUSTOM-HAWK-VACUUM-AND-FUEL-PUMP-TESTER-u-/200815171141?_trksid=p4340.m1850&_trkparms=aid%3D222001%26algo%3DSIC.CURRENT%26ao%3D1%26asc%3D11%26meid%3D2562473329148028097%26pid%3D100011%26prg%3D1005%26rk%3D1%26sd%3D300773735530%26 thats the tester. Any bit of help would be great
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That port on the ovc pipe is not part of the intake manifold and is before the throttle body itself. It should never register vacuum and only serves as a boost reference for the wastegate. It should only register pressure when the turbo is producing positive pressures which, unless the turbo where incredibly small and the engine quite large, will only be while the engine is under a load and not sitting still. As mentioned you want to take your reading off the nipple on the manifold itself closest to the driver side fender. Either the one closest to the firewall or the one by itself below the 3.
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The nipple on the OVCP is connected to the WG actuator because it reads the boost, which pushes the diaphram in the actuator to move the arm, which then opens the waste gate. However, that port reads ONLY boost. Not Vacuume. The third port and the bottom port read both boost and vaccume just the same. The other two ports (front and middle of the row of three) read boost or vaccume under certain conditions.

 

Either the front or middle port will only read pressure at a certain RPM. So therefore the rear and middle port would be ideal for reading boost AND vaccume. And If your car is a manual then you can also use the nipple that's on the rear-most port on the intake manifold that sticks up. This port is used on automatics to run the valve body in the transmission. 5-speeds obviously don't need the port. If I can get time for a picture then I'll post it up. Hope this helps!

 

- Charles

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The nipple on the OVCP is connected to the WG actuator because it reads the boost, which pushes the diaphram in the actuator to move the arm, which then opens the waste gate. However, that port reads ONLY boost. Not Vacuume. The third port and the bottom port read both boost and vaccume just the same. The other two ports (front and middle of the row of three) read boost or vaccume under certain conditions.

 

Either the front or middle port will only read pressure at a certain RPM. So therefore the rear and middle port would be ideal for reading boost AND vaccume. And If your car is a manual then you can also use the nipple that's on the rear-most port on the intake manifold that sticks up. This port is used on automatics to run the valve body in the transmission. 5-speeds obviously don't need the port. If I can get time for a picture then I'll post it up. Hope this helps!

 

- Charles

thanks that really helped and i do have a 5 speed

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http://www.starquestclub.com/forum/index.php?showtopic=28042&hl= vaccume ports&st=40 (The "= vaccume ports&st=40" is included in the URL)

 

I suggest doing a VAC line delete. I did it on my car and it has helped my car a lot. Throttle response quicker and less useless eqip to deal with. Also helps narrow a possible boost/vaccume leak. All that's on my car is the VAC advance (front port), AC and Cruise lines (Lower Port), and BOV (rear port). If you don't have a BOV then you should only have the front and lower port hooked up.

 

PM me if you need any further help on removal or have questions

 

- Charles

 

If you go to the very last post in the thread it'll show a diagram explaining what each port does on the TB.

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  • 2 years later...

???

Where lies your question, go to the VERY LAST POST IN THE THREAD. Sorry for the caps but you have to realize there are three pages to the thread and the link gets you to page one.

http://www.starquest...40#entry1305900

 

 

 

 

 

on a side note,

http://bios.weddingbee.com/pics/127605/zombie-thread.jpg

Edited by Skullzaflare
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