Fuel Pressure Problems

[farmer]

I finally installed my engine and have it running. Problem is fuel pressure at constant 23000+ psi. I have an lb7 engine with lbz pump. Tried adjusting b1010 as stated in numerous posts with no effect. Figured fpr was bad so I installed new lb7 fpr I had. Fuel pressure is now 26500+. Any ideas would be appreciated.

 

[TrentNell]

Are all your grounds hooked up ? sounds like the regulator/wiring would be the source from what little bit I know about the subject especially since the new reg didnt fix it i would be checking the wiring myself . Single cp3 or dual ?

 

[S Phinney]

The fpr controls the pressure so if you have a LBZ pump and use a LB7 fpr you should not have to adjust the b1010 tables. If current keeps the pressure at max psi then you must not have current to the fpr. Check for connections.

 

[othrgrl]

Current is what keeps pressure so with it unplugged (or a bad connection/broken wire) it defaults to full pressure. Also check to be sure the rail pressure sensor is plugged in - if it is actually flat line constant that is usually the case. An unplugged regulator will still have some variation in pressure.

 

[farmer]

Single cp3. Fuel pressure sensor is pluged in. Grounds are hooked up, I may clean and reinstall today if I can not find broke wire. Why does engine sound better when I fake it out by adjusting b0203 down to commanded fuel pressure??? Why did pressure go from 23000+ to 26000+ with fpr change?

 

[farmer]

I checked fpr wires for continuity and seem ok but can not get any volts to show up at the plug while engine running. Pins etc seem good on plugs.

 

[2500HeavyDuty]

is it always at 26kpsi, or does it drop down when you try to take off in gear

 

[MMLMM]

check your fuel temp sensor connection and sensor too.