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View Full Version : boost gauge install, wrong feed? reads low



black99.5a4
11-21-2008, 12:24 PM
I tapped vacuum from the line between the manifold and the FPR as I had read in a few DIY online. Should I have done this or is there another place I need to go tap for an accurate reading? I ask because I have a stewart warner gauge and i know my car pulls harder then 10 psi and its all that its reading.

djwimbo
11-21-2008, 12:30 PM
That's the same place I tapped into and I get very accurate results.
on a "Stage 2" software you should be in the range of 18-20psi.

Stewart Warner like dis?
http://i305.photobucket.com/albums/nn218/djwimbo/Tunnel%20Park%2008/DSCF1399.jpg

black99.5a4
11-21-2008, 12:36 PM
that exact gauge.. yep yep.. the gauge doesnt even show a spike.. it reads up to 10 and then holds it and then falls off, this is in 1st, 2nd, 3rd and 4th.

LDetter
11-21-2008, 12:46 PM
Hmm, did you make sure you didnt put a kink anywhere in the plastic hose to the boost gauge? Assuming yours came with a plastic hose, my VDO gauge did.

black99.5a4
11-21-2008, 12:48 PM
i havent made sure of that yet, i have my son so i cant go out and look.. only place it could of kinked is right under the pod b/c i am using a column mount.

djwimbo
11-21-2008, 12:51 PM
I used as little of that plastic hose as possible. I hate compression fittings.

Does the gauge seem responsive to changes in idle vacuum? Like when you barely touch the throttle, you should see vac drop, then jump back up real quickly

zrowcool
11-21-2008, 12:53 PM
yeah if it kinks the reading would be low. mine kinked right before the firewall when i first installed. i ended up putting the plastic line inside of rubber vac line to give it some rigidity

black99.5a4
11-21-2008, 12:54 PM
yes, vacuum side is very responsive.. if i let it idle in neutral and hit the gas to about 5k it also reads 2psi of boost.

could i have gotten a bad gauge? my setup has no compression, b/c i have the column pod it comes with a 90* barbed fitting.

jonsilverio
11-21-2008, 12:57 PM
be carefull with connecting anything tied into your fpr because if the line gets loose and you have a leak you will run lean and you might blow your motor, so it might be a good idea to see if you find another place to tap into.

LDetter
11-21-2008, 12:58 PM
Whats your vacum at idle?

njm23
11-21-2008, 01:00 PM
be carefull with connecting anything tied into your fpr because if the line gets loose and you have a leak you will run lean and you might blow your motor, so it might be a good idea to see if you find another place to tap into.

Which is why my line comes off the front of the manifold not by the fpr

black99.5a4
11-21-2008, 01:08 PM
Whats your vacum at idle?

20 in nuetral with parking brake on

djwimbo
11-21-2008, 01:10 PM
be carefull with connecting anything tied into your fpr because if the line gets loose and you have a leak you will run lean and you might blow your motor, so it might be a good idea to see if you find another place to tap into.

First off, you would probably notice the lack of power, and second, I put a $0.25 clamp on the hose so it doesn't pop off.

18psi did make my line blow off once. It ran like crap at idle and I fixed it <2mins after it happened.

LDetter
11-21-2008, 01:11 PM
Thats about right if the engines cold. Mine is at 20 when its cold, 22 when its warm. I taped into the vacum line off of the inake manifold that goes to the dv, maybe try switching it to there and see if anything changes.

a4mafia
11-21-2008, 01:29 PM
i tapped into a line off the turbo. is that why it wouldnt be reading any vaccuum??

black99.5a4
11-21-2008, 01:41 PM
was told my n75 or n294 i think it was, could be bad. any way of checking these? I have vag com at my disposal and i'm getting no codes.