can't seem to get my 88 TII to idle below 1k rpms. checked fuel pressure today and it reads 40psi at 1300rpms. so i hooked the FPR vacuum line directly to the manifold and it still reads 40psi. even in boost it reads 40psi. only at the instant i let off the gas does the pressure go higher than 40. and never goes under 40. i'm confused.

do i have a faulty FPR? and would high fuel pressure make it not idle?

 

Is that high? I was under the impression ~40 was normal.

 

40 psi is at atmospheric pressure. At idle, and you don't seem to have and idle because you mention thirteen hundered rpm, the pressure should be closer to 30 psi.

Either the vacuum line to the FPR is not going to the right nipple on the manifold, or the FPR is kaput (not likely in my humble opinion).

So run a vac line to the FPR. Start the engine and look at the fuel pressure. Now suck on the vacuum line. The pressure should drop. If it does, then somehow your connecting the vac line to a source that is, well, not the right nipple.

Not all nipples on the throttle body are vacuum, in case that is where your putting the vacuum line for the FPR.

You might explain in detai how your looking at fuel pressure. Like how you have the gauge installed.

 

i cut out the short hose that connects the primary and secondary fuel rails and made a big loop and spliced in a mechanical pressure gauge. first checked pressure when hooked up normal, then checked pressure with no vacuum line on the FPR, then hooked the FPR vacuum line to the same nipple that goes to the MAP sensor. everything reads 40psi.

if it is a FPR failure, do i go with another stock unit for $80 at autozone, a mazda unit, or go with aftermarket like Aeromotive?

the only mods i plan on doing in the near future are air/water intercooling and a megasquirt. if my current mods plus these doesn't require an adjustable FPR, then i'm ok with using another stock one.

 

well, it should be no surprise to you that it isn't the FPR.

next thing i'm going to try is swapping out the rtek 1.5 chip for my stock ones to see if maybe that is the cause.

if not that, maybe a vacuum leak is the culprit.