Overwhelmed fuel pressure regulator
 

Hi,

I have an early NB which has a returning fuel system unlike the returnless ones you have in the US NB. Anyway, my fuel pump ---- itself and the only pump we had spare was a Deatschwerks DW300.

The car is working fine with the DW300 with the exception of it being always rich at startup and in open loop, so I assumed the regulator was getting overwhelmed.

If this happens to be the problem, I wanted to know if you guys can see any problem with it being left in this overwhelmed state if the tune is modified to suit?

Do you think the pressure will deviate much?

Cheers

Why not just install a proper adjustable FPR and set it to the proper fuel pressure?

If you let it over pressure the FPR as it is now, you may end up with a hole in the FPR diaphram, that will dump raw fuel into the intake and on top the piston.

The pressure won't remain constant and you'll need to constantly adjust the tune. I wouldn't just leave it like that.

This is the regulator on the returning NB rail (BP5B 795300-3730):

https://www.miataturbo.net/attachmen...ine=1341372920

I think instead of dicking around with aftermarket regulators, I might swap to a less baus fuel pump.

I'm guessing the usual swap is a Walbro 190LPH unit. Do you know of a quieter alternative? Would I be mad to consider swapping in another OE unit?

Cheers

These look like the go, although I don't know what the stock pump put out:
http://www.bosch.com.au/content/lang.../fuelpumps.pdf

I'm guessing it is similar to the NA pumps you guys use.