Anyone running a return style fuel system?

[LS2 KLR]

I was just wondering what your fuel pressure was running. I am at 27 on idle and 32 under a load. Today my car started bogging when it got into the upper rpms at wot? I was thinking it might be the filter but also thought my fuel pressure was alittle low?

 

[dollarbill]

Yes your fuel pressure is low. I could be the pump or the regulator. While running, pull the vacuum line off the regulator and see what it goes up to. It should be close to 50 with the vacuum unhooked and 35-45 with it attached. I have mine set at 40 with vacuum. It may also be the filter, which would be the cheapest to replace. a new Motorcraft filter is $5-8.

 

[LS2 KLR]

It was at 34 with the tube off. What is strange is in first and second gear in the opper rpms it drives pretty bad and sputters at wot. In third it isn't as bad and in fourth doesn't appear to stumble It didn't do this for the first 2-3 weeks with the new shortblock. I'm gonna pull the filter and also check my plugs. Anyway it could be a coil? I'm not sure what the characterists are of one gone bad but my car does have over 90K miles.

 

[dollarbill]

You can check the resistance of the coils, but thats about it. If you only had 34 psi with the vacuum off then its low. When you crack the throttle does the pressure drop off? It shouldn't, especially when no load is present. Replace the filter and check it again. It could also be the regulator. Maybe a friend has a stock one you could put on the try it.