I have a Defi boost gauge that I got from the rx7store about 9mos ago. I recently decided to move it from the center speaker mount to a column mount. I took it out about 3 weeks ago, and when I went to install it today, it was ready 3psi. Just sitting there! I don't think I walked into a high pressure zone in my garage, so what gives? It read 0psi when I took it out of the car and I never had a problem with it before. Can anybody try and explain this? Is there a way to adjust it back to normal? I didn't see any adjustment screws on the back. I really want to get my car back together so I can drive it. I'm thinking that my only option is to return it and get a new one. Please help!

 

put the nipple back on the plenum and start the car then shut it off. It should calibrate itself.

 

Sorry for being vague, but I have the mechanical boost gauge, so when it is not plugged into anything (and out of the car), it should read 0psi (atmospheric), right?

 

yes it should but my when I unplugged my autometer it went to abt 2 and then when I put the nipple back it went down to 1. after starting the car and shutting it off it was back to 0. this was my cheapo autometer and your defi should not do it so it may be a bad guage.

 

okay thanks. i'll try calling the rx7store tomorrow

 

negative dude, when car is off, it will really depend on what the barometric (SP?) pressure is so it wont really always be at exactly 0.

 

i had the same problem with my defi. infact when the car is off it sits at almost one pound. kinda bugs the **** out of me. i have done everything, including posting this topic before. try my name(suprfast) and the search word(defi) and see what you can come up with. hell, let me do it real quick
https://www.rx7club.com/forum/showth...highlight=defi
hope that helps if any
kris

 

I understand that being a mechanical boost gauge it will read atmospheric pressure (barometric, whatever), plus whatever the turbos are spooling. But, I just went to weater.com and the current pressure is 30.26" of Hg. This converts to 14.86psi. Assuming that the gauge zero is 14.7psi (standard atmospheric pressure), this is only a difference of 0.16psi. Yet my gauge still says 3psi! What gives?

[edit:] Oh, and suprfast, I did search and found your post, wasn't exactly what I was looking for. thanks though.

 

oi, i never knew it was that much off

 

This is not a solution to your problem, but may provide some reassurance. I always check my boost gauges for accuracy and it's simple to do. Borrow a quality "race" tire gauge, preferably one used for lightweight cars that will only read to 25 psi or so. Using the tire gauge inflate an air tank to the maximum reading on your boost gauge. Tee the gauge into the tank and see if it reading matches the tire gauge. Then repeat at other increments. For the FD I check at 5 psi, 7 psi, 10 psi and 12 psi.

The boost gauge merely reads pressure and high quality tire gauges are already caliberated, so using to to verify the boost gauge's reading is simple to do.

 

This won't solve your problem, but a mechanical boost gauge should read 0psi no matter what your local pressure is. It gives the difference between local pressure and the pressure you feed it via the tube. So if yours is reading 3psi it's probably just a matter of finding a way to turn the needle by hand until it reaches 0psi...or something.

 

did anything ever come of this. . . i just recieved mine in the mail today and it reads 5psi IN THE BOX!!!

paul

 

If its reading that high it was probably damaged in shipping, I would get it exchanged.

 

You should be able to get the needle to move. Have you tried disassembling it and finding some kind of adjustment screw? If its mechanical and the needle cant be adjusted then maybe the scale behind it can be moved so that where it sits at 0psiG reads correctly.

 

My autometer gauge is also off by a couple pounds.

If your Defi gauge is reading 5psi new, then its defective or damaged. As far as the 3psi off all of a sudden, could it have been dropped or bumped hard while it was out of the car? I don't see how it could have wandered just sitting there unmoved.

 

theres no way to take them apart w/o having to replace parts. . . youd tear it up just trying.

paul

 

i just talked to defi about it. . . theyre very sorry, but you cant do it. you HAVE to send it back. im not in the business of tearing up expensive parts when i can just get a new one. . . hopefully.

paul

 

If its any consolidation, even a zero reading with the engine off is no guaranty that the gauge is accurate. My VDO mechanical gauge sits at zero, but reads two pounds high at 10psi (ie. it reads 12psi).

-bill

 

consolidation == consolation.

I blame it on too much coffee.

 

**** i'd hate to be running 14 instead of 12psi....i guess you get what you pay for..