Why adjustable fuel pressure regulator?

CliffyC

Member
Joined
Feb 25, 2007
Can anyone explain to me why an adjustable fuel pressure regulator is necessary when a Bosch 237 can be used? It comes factory on many late '80's and early 90's GM 3.8 fuel injected motors. It's set at 43 psi and never changes. I believe almost all chips are written for 43 psi so why adjust?
 
Well, for all intents and purposes, with todays modern chips with so many adjustable parameters an adjustable FPR probably isn't all the necessary. I haven't touched mine in years. If i have to make a mixture adjustment, it's just a matter of tweaking fuel either in the chip or Translator.
 
I think some of the adj fp regulators are made with a bigger opening for the return line

David
 
the adjustable regulator takes the production tolerances out of the equation- instead of begin +/- a few psi, you can set it where you want it.
 
Maybe it's just me but when I had an adjustable FPR seemed like I was always checking and tweaking it. Now with the 237 I never touch it.
 
This is so obvious that I never thought of it. Thanks for bringing it up. A real plus for the stock-appearance guys.
 
The 89 turbo T/A came with the 237 fp reg. I bought one to have as a spare for my adjustable reg. from Autozone some years ago and forgot about having it until seeing this thread, since i never had to use it.

It had some tarnish on the gold finish of the reg. so i took some 60 grit sand paper and then some 800 grit and wet sanded it to smooth it out and finished with some Eagle One wheel polish and it looks almost chrome now.

Tomorrow i'm going to install it to verify it still works and check the pressure.
 
I installed the 237 fp reg. and it still works and the press. is 45 psi static. I'm going to leave it on and run it for awhile.
 
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