But, in that case, isn't there a regulator somewhere, to make sure
the pressure stays around, in this case, 18psi? Same probably holds
true with the '91 that the original poster mentioned. Any extra fuel
will get rerouted back to the tank, IIRC.
Only way to know for sure would be to check a manual. (Joe might
I just dug out the old shop manual for my Blazer. Here is what I have found.
The pressure regulator is located on the inlet of the TBI unit. There is no
access port to measure the regulated pressure. The fuel pump is supposed to
deliver pressure between 13 - 18 PSI. In order to measure the pressure you
need to install a Tee fitting on the fuel inlet to the TBI. The regulator is
supposed to regulate pressure between 9 - 13 PSI depending on engine load.
Thinking back, I was able to tell when I had a fuel pressure problem with
mine just by watching it run. The "Injectors" actually mount above the top
of the TBI and spray down the throat like two sprinkler heads. If you see a
nice even mist you probably have adequate pressure. If you see the nozzles
dribbling fuel out you have a problem. My experience has been that when the
pump goes bad, your car will be undriveable. Pressure just slightly below
the proper range is usually remedied by installing a new fuel filter. I hope
this helps. - Gary
Thanks for the responses. My manual shows the regulator inside the throttle
body assembly and yes the injectors (2) sit above and spray down. The
problem is that the fuel pump is delivering zero fuel - the electrical
circuit checks out so I have to conclude that the pump is shot. The only
psi rating I could find was in the TPI & MPFI section and that was 34 to 39
PSI. Guess I'll call around when the shops open in the morning and see what
I can find for replacements. Thank you.
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