Boost gauge only reads negative boost?

[garyrmills]

when i fitted my boost guage it worked fine for a week or so then it started to only read negative pressure.
ive got the pipe t'd into the dump valve breather on the top of my oo7p its not a blocked pipe as ive changed the pipe for stronger pipe and its still doing the same? the boost wont read over 0 psi. ive also tryed a new guage and t peice any ideas would be great
thanks in advance gary

 

[s3_kev]

try t'ing it correctly, you need to T into a inlet manifold vaccum line

 

[djdougalno1]

i dont think it makes much difference any of the vacuum hoses will do have u got any leaks like around the t piece any split hoses

 

[garyrmills]

Any chance of pics as im not sure which pipe to go to either that or abit of an explanation please mate. Is strange that it worked on the hose from top of dv before and not after a while tho?

 

[s3_kev]

i dont think it makes much difference any of the vacuum hoses will do have u got any leaks like around the t piece any split hoses

it does make a difference as you need manifold pressure not just any old vaccum pressure, the line from the dump valve goes through the n249 valve so its never going to give correct readings.

 

[s3_kev]

Any chance of pics as im not sure which pipe to go to either that or abit of an explanation please mate. Is strange that it worked on the hose from top of dv before and not after a while tho?

it does seem strange that it was ok and now its not, yeah it does work using the line from the dump valve but its not an accurate enough route, the line from the fuel pressure regulator is a good one thats the little valve on the right hand side of the fuel rail as you look at it

 

[garyrmills]

nice 1 il have a looky tommorow

 

[S3 Nattie]

You could also T it into the fuel pressure regulator. Check that the piping that goes to the gauge has not folded or twisted on itself.