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Wacky Fuel pressure

Did you drill out the hole in the replacement banjo bolt? If you compare them, the factory hole is larger. I drilled mine out when I installed it and mine doesn't flutter.

I can post pics when I get home.

[/QUOTE]ok, whatever you are saying has gone well over my head. please explain. [/QB][/QUOTE]

Let me clear it up a bit.
Someone mentioned that their fuel pressure was fluctuating a bit and you said it was due to the stock FPR and that with an aftermarket FPR the fuel pressure would be much more stable.

My situation is the following
A rewired Walbro 255lph pump with a B&M Commandflow FPR. With the hose off my FPR I attempt to set the base pressure to 50psi however the needle on my fuel pressure gauge still fluctuates approximately +/- 1psi. However when I put the vaccum line back on the FPR the fuel pressure gauges fluctuates much more to a degree of +/- 4psi.

This should not be the case according to your statement about the FPR stablizing the fuel pressure. I am now thinking that due to the B&M utilzing the stock diagphram from the stock FPR that may be the reason why it is fluctuating. I had a SpoolinUp Unit on my car for a short period of time and I do not recall the fluctuations on the fuel pressure gauges.

So basically I think I just answered myself but add your comments if you like.



Well-known member
Oct 16, 2002
Massillon, Oh.
Thanks Joe I drilled out the hole to stock size and now the gauge reads within 1 psi. That makes me feel a little better.
Now with my 255 low pressure pump and all stock fuel system with the vacuum line off it is right at 44-45 psi. With the line connected it drops to only 40-41. I thought it should drop more but that is probably cause of my pump huh?


Well-known member
Feb 23, 2001
Kennewick, WA, USA
The B&M unit that modifies the stock FPR is only able to *raise* the base fuel pressure not lower it.

i.e., the B&M unit is worthless if you have an upgraded pump.

Mark Rieb
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