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Discussion Starter #1
What should the fuel pressure be at the rail on a 96 LT1?

Is there an acceptable range?

Thanks
 

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I believe the LT1's aren't much different than the L98's, so when the pump primes the rails it should be around 40-42psi. Once started it should be between 38-40.

Someone correct me if I'm wrong.
 

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I believe the LT1's aren't much different than the L98's, so when the pump primes the rails it should be around 40-42psi. Once started it should be between 38-40.

Someone correct me if I'm wrong.
You got it. That's right there in the neighborhood.

Steven
 

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:agree: fuel pressure should be AROUND 42 psi with key on/ engine off.

when the engine starts, intake manifold vacuum will work against the spring in the fuel pressure regulator and lower the pressure, till you open the throttle and drop manifold pressure, then fuel pressure will revert to the higher ''spring only'' control point...this crude method of varying injector delivery in different modes of engine operation has proven effective and is widely applied.

fuel pressure ''around'' 42 psi is ok...in ''open'' loop the ecm is programmed to pulse the injectors in excess of true fuel demand, and spark timing is also conservative...in ''closed'' loop, the ecm offsets from its base programming to pulse injectors to balance the o2 sensor output.
 

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Discussion Starter #5
Mine was not running right today, and actually quit running at the auto parts store.

I bought a gauge there and checked the fuel pressure - less than 20 psi and falling. In fact, once the gauge was purged, and the engine cranked, no pressure.

Replaced the fuel pump (in their parking lot) fired up the car, got 40 psi on the gauge and drove it home.

I think this fuel pump may have been failing for some time now. I've had other posts to DC on intermittent problems with the car. Hopefully this fixed all of that.

Thanks for your help here.
 
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