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FPR too weak ?

565 Views 5 Replies 5 Participants Last post by  79-280-ZX
Finally got around to measuring fuel pressure on 75-L28 N42,N42 .

Hooked gauge into CSV line, and reading 26 PSI .

Rev engine, little change . Crimp off return line and pressure
goes up quick.

Crimp off vac line to regulator, and no change at all, revs or not.

Seems like a worn/weak spring in regulator ???

Am going to change over winter when I convert to a rail...but in the
meantime is it doing anything significant ( the lower pressure ) .

Z-On ...
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Pull the vac hose -off- the regulator and check the pressure. If that gauge is accurate, the pressure is low.
yeah, id say its too weak too. shouldnt it be around 45psi at idle? im not sure....why cant you just replace it now? its not that hard and fairly cheep...make sure to contact pallent for a new fuel rail when you are ready...take a look at my pictures to see what he makes them like! hes an artist!
Mines 29 at idle and 38 with fpr vacuum line pulled. 26 doesn't seem that bad.
It depends on how accurate the gauge is. If it goes from say 26 to 36 or so with the vac line pulled, it's probably a gauge issue.
There is a direct relationship between intake manifold vacuum and fuel pressure, so you must measure both at the same time.

Read this Another Fuel Pressure / Volume Test.
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