BigT-65

I have a vacuum/fuel pressure tester and I am not sure it is working properly. It does not leak. Is there a convenient way to pressurize this thing to see if it goes through the psi range. I don't have a good fuel pump to test it on. Anyone have a technique for this?
Thanks

BigT-65

I went ahead and attached a syringe full of water to the tester and applied pressure. The dial went through the entire range on the gauge. So I guess it is working. This doesn't prove any accuracy though. I did notice that before applying pressure the pointer is approximately 1 psi prior to the 0. So maybe when it reads a pressure of 3.5 it is really 4.5, which is still not enough for my car.

CrossedUp

The only way that I know of to accurately calibrate a pressure gauge is with a Dead Weight Tester. You could, I suppose, compare your gauge to a known calibrated one connected to the same source.

BigT-65

Thanks, but I don't have one of those. I might be cheaper to buy a new gauge. I've had this one for over 30 years so I guess I should.

Bill Pilon

It is properly more accurate than a new one considering the quality of products today.

If you are worried about very accurate fuel pressure use a mercury column to check it.

Bill

BD104X

If you're not looking for NASA level scientific calibration, I would borrow a friends gauge and attach them both to a vacuum pump and compressed air source with a T fitting. If they both read the same, you're probably good.