Issopro fuel P gauge vibrating ?

[PRout]

In a matter of about 6 years I went through 2 Isspro FP gauges. They both worked for a couple yrs, then started rattling with the rhythm of the VP44. Isspro replaced replaced both at no charge and as said above, they gave me a 3rd gauge along with their snubber fitting. since installing the snubber, no more gauges getting hammered by the VP. Snubber is the answer, but once the gauge has been hammered to the point of rattling, it is probably shot.

 

[Fishin Guide]

When in doubt, make your own snubber.

A steel fitting can easy be filled partially with solder or expanding foam. Use a small drill bit when completely dry or hardened. Instant snubber and it works.

I have been using the solder technique for many years on the old race cars.

Don't forget a good isolator also acts as a snubber to some degree.

Dave

Diesel Distributors USA

 

[Pliska]

What drill size are you using on a fuel pressure gauge?



Thanks,

Michael Pliska

 

[Fishin Guide]

What drill size are you using on a fuel pressure gauge?



Thanks,

Michael Pliska

Michael,



1/16" to 1/32" for boost depending on plug depth. I have gone bigger with a deep plug.



Fuel and oil usually around 5/64". Again, depends on what I am building and what the use is. Typically, you use a larger hole when at the engine, smaller at the gauge. Obviously, the engine side is better to use.



After my first Isspro gauge rattled many years ago this is the first mod I have done since. My dad and I both have a combine 250K on our boost gauges with no rattle. I run both a 60# along with a 100#. He runs a 60#. Fuel gauges are still fine, although I pulled mine now that I run over 40psi at idle. His 30# gauge was a rattling hand me down from my original set and the snubber stopped the rattling while extending it's life.



The other key to getting boost gauges to last is to get the tapped point away from the valve face and into the horn where pressure is more stable. The valve opening/ closing event along with the charge air changing pressures as a result kill the gauges.



The air example explins what happens to the fuel pressure gauges as they get hammered by 15-30 psi of pulsing fuel pressure. All this due to a sudden drop then spike in the pressure leading into the VP44. Being fuel, location is less important as the compressability is far different than air. But the snubber still is just as effective.



How do you know how big to make the hole? I know how fast the gauge drops off with the truck off. I compare that to the snubber time, It will be slightly slower to drop. This is the resistance to shock.



Simple, effective and cheap!



Oh, if you are loosing senders, this is the easist way to save them! I have an Edge sender that is notorious for failure still kicking after 40K with rock steady pressures.



Dave

 

[RJWEST]

I ran rubber hose from the vp to the firewall, than copper to the gage, For a snubber I drilled a very small hole in a cut section of bolt and installed in the hose at the VP .

gage fluctuates a little, But nice and quit. .