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Fuel Pressure Regulator Works Backwards From Intended
Set up a FPR on my '90 motor, but as the title suggests I get backwards results. As I increase the pressure, the motor gets less fuel. I have it set up as required; from the rail to an in/out port, and bottom port to the tank return. Still have stock rail with stock FPR if that makes a difference.
I know Ive got the lines correct, because when I pinch the return line after the FPR the pressure increases.
Theres a direct relationship between the number on the pressure gauge and the number on the wideband display. Also the motor would tend to die after a (very lean) rev.
Ive checked the fuel lines from the pump to the rail, and verified visually just about 10 times that the line Im using is coming from the return side of the rail.
setup is tank->filter->rail in->rail out->FPR in/out->FPR return->tank
One option I have to get around this is to use the FPR to convert to a returnless rail, but Id like to leave that as a last resort. I dont even know if the rail has the proper flow characteristics to make that happen. I'd like your thoughts on that as well.
The only thing that makes sense to me if you accidentally have it hooked up backwards - the return line is the most-forward hardline in the engine bay, source is behind that.
Do you still have the stock FPR installed? If so, that will prevent the upstream AFPR from working.
Some others have left the original FPR and added one after it, but I don't remember who, or how they plumbed it.
Keuzy, if you want to use -AN connector to replace the stock FPR, the correct P/N is FT061-001. The one shown on-line for Miatas, in various places, WILL NOT FIT.