I'm trying to resolve a fuel system issue. I have a Vortech V1 package on a 97 Cobra pullied at 8 lbs. The T-Rex inline pump with the factory pump was running at 40psi at idle with increases to 43 - 45 on boost. When first starting the car up cold I get 40 lbs pressureat idle. If I yank the power feed wire to the T-Rex pressure drops off to the 22 - 25 lbs but the car keeps on running. This seems odd as Vortech is telling me the T-Rex should only be increasing pressure under boost. With 40 psi at start up after driving around for 5 - 10 miles pressure slowly drops off to the 22 - 25 lbs and the pump gets loud. (This is a new development, the car ran for years without issues, always at 40 psi) Yank the power feed to the T-rex at that time and pressure stays at 22 - 25, pump shuts off and stops whining, the car keeps running. The coincidental drop off to 22 - 25 and the T-Rex whining very loudly leads me to believe that the T-Rex has the problem and not the intank pump. At this point I'm wondering if I should replace the in-tank pump with a 255lph Walbro and remove the T-Rex. Its certainly the cheaper of the 2 options. Leads me to two questions: 1. How many psi should I be getting out of the stock pump? (To verify if it is bad or not) 2. Can I use just a 255lph intank pump and have enough fuel pressure for my current setup? Or do I need the T-Rex on top of it?
