Bouncing fuel pressure gauge needle

[dan juhasz]

I installed Promax Carbs braided fuel inlet lines on the six pack to make servicing the carbs easier. It comes with a mechanical fuel pressure gauge. Never had a fpg on any of my cars. It bounces all over the place when running. Between 8 and 12 psi. New fuel pump ( Carter ) is on the the car, the hp model for 440 six pack cars. Is this normal?
I wanted to post a short video but I guess only photo’s are upload-able.

 

[493 Mike]

I installed Promax Carbs braided fuel inlet lines on the six pack to make servicing the carbs easier. It comes with a mechanical fuel pressure gauge. Never had a fpg on any of my cars. It bounces all over the place when running. Between 8 and 12 psi. New fuel pump ( Carter ) is on the the car, the hp model for 440 six pack cars. Is this normal?
I wanted to post a short video but I guess only photo’s are upload-able.

I have never seen a FPG on a mechanical pump engine. I would imagine it may react to the diaphragm motion?
Mike

 

[Bird 426]

Just read an article on this. Even a fluid filled gauge does not like being on the engine, heat. Plus, from my own experience, you need a fuel pressure regulator, put the gauge there, down on the frame horn by the fuel pump. Once you get your fuel pressure under control, you can put the gauge back in it's box. 8 lbs is a bit too much for your Sixpack. I cut mine down to 5, maybe 5.5. At 7.5 my plugs were always fouled, no matter what I jetted to correct.
Just my experience.
Good luck

 

[Daves69]

Does the needle smooth out with increased RPM?

My cheap Jegs oil filled doesn't flop around @ idle.
Then too, it doesn't like the under-hood heat when hot as Bird indicates.

 

[hunt2elk]

Sounds like you have one of the Carters that was sent out with to stiff of spring, causing high pressure. I had a couple that were at 11-12 psi. Like stated above, you need to get that down to around 5 psi.

 

[dan juhasz]

Does the needle smooth out with increased RPM?

My cheap Jegs oil filled doesn't flop around @ idle.
Then too, it doesn't like the under-hood heat when hot as Bird indicates.
View attachment 1832783

No it bounces around violently

 

[dan juhasz]

Sounds like you have one of the Carters that was sent out with to stiff of spring, causing high pressure. I had a couple that were at 11-12 psi. Like stated above, you need to get that down to around 5 psi.

I didn’t realize there was an issue with some. I have the standard 384/440 Carter fuel pump, maybe I’ll swap them out and see how it reads.